chemistry

Research roundup: 6 cool stories we almost missed

animals, Biology, chemistry, fermentation, microbiology, Physics, psychology, robotics, Science, social networks / Rejus Almole / December 1, 2025

The assassination of a Hungarian duke, why woodpeckers grunt when they peck, and more.

Skull of remains found in a 13th century Dominican monastery on Margaret Island, Budapest, Hungary Credit: Eötvös Loránd University

It’s a regrettable reality that there is never enough time to cover all the interesting scientific stories we come across each month. In the past, we’ve featured year-end roundups of cool science stories we (almost) missed. This year, we’re experimenting with a monthly collection. November’s list includes forensic details of the medieval assassination of a Hungarian duke, why woodpeckers grunt when they peck, and more evidence that X’s much-maligned community notes might actually help combat the spread of misinformation after all.

An assassinated medieval Hungarian duke

The observed perimortem lesions on the human remains (CL=cranial lesion, PL= Postcranial lesion). The drawing of the skeleton was generated using OpenAI’s image generation tools (DALL·E) via ChatGPT. — Credit: Tamás Hajdu et al., 2026

Back in 1915, archaeologists discovered the skeletal remains of a young man in a Dominican monastery on Margaret Island in Budapest, Hungary. The remains were believed to be those of Duke Bela of Masco, grandson of the medieval Hungarian King Bela IV. Per historical records, the young duke was brutally assassinated in 1272 by a rival faction and his mutilated remains were recovered by the duke’s sister and niece and buried in the monastery.

The identification of the remains was based on a contemporary osteological analysis, but they were subsequently lost and only rediscovered in 2018. A paper published in the journal Forensic Science International: Genetics has now confirmed that identification and shed more light on precisely how the duke died. (A preprint is available on bioRxiv.]

An interdisciplinary team of researchers performed various kinds of bioarchaeological analysis on the remains. including genetic testing, proteomics, 3D modeling, and radiocarbon dating. The resulting data definitively proves that the skeleton is indeed that of Duke Bela of Masco.

The authors were also able to reconstruct the manner of the duke’s death, concluding that this was a coordinated attack by three people. One attacked from the front while the other two attacked from the left and right sides, and the duke was facing his assassins and tried to defend himself. The weapons used were most likely a saber and a long sword, and the assassins kept raining down blows even after the duke had fallen to the ground. The authors concluded that while the attack was clearly planned, it was also personal and fueled by rage or hate.

DOI: Forensic Science International: Genetics, 2025. 10.1016/j.fsigen.2025.103381 (About DOIs).

Why woodpeckers grunt when they peck

A male Pileated woodpecker foraging on a t

Woodpeckers energetically drum away at tree trunks all day long with their beaks and yet somehow never seem to get concussions, despite the fact that such drumming can produce deceleration forces as high as 1,200 g’s. (Humans suffer concussions with a sudden deceleration of just 100 g’s.) While popular myth holds that woodpecker heads are structured in such a way to absorb the shock, and there has been some science to back that up, more recent research found that their heads act more like hammers than shock absorbers. A paper published in the Journal of Experimental Biology sheds further light on the biomechanics of how woodpeckers essentially turn themselves into hammers and reveals that the birds actually grunt as they strike wood.

The authors caught eight wild downy woodpeckers and recorded them drilling and tapping on pieces of hardwood in the lab for three days, while also measuring electrical signals in their heads, necks, abdomens, tails, and leg muscles. Analyzing the footage, they found that woodpeckers use their hip flexors and front neck muscles to propel themselves forward as they peck while tipping their heads back and bracing themselves using muscles at the base of the skull and back of the neck. The birds use abdominal muscles for stability and brace for impact using their tail muscles to anchor their bodies against a tree. As for the grunting, the authors noted that it’s a type of breathing pattern used by tennis players (and martial artists) to boost the power of a strike.

DOI: Journal of Experimental Biology, 2025. 10.1242/jeb.251167 (About DOIs).

Raisins turn water into wine

wine glass half filled with raisins — Credit: Kyoto University

Fermentation has been around in some form for millennia, relying on alcohol-producing yeasts like Saccharomyces cerevisiae; cultured S. cerevisiae is still used by winemakers today. It’s long been thought that winemakers in ancient times stored fresh crushed grapes in jars and relied on natural fermentation to work its magic, but recent studies have called this into question by demonstrating that S. cerevisiae colonies usually don’t form on fresh grape skins. But the yeast does like raisins, as Kyoto University researchers recently discovered. They’ve followed up that earlier work with a paper published in Scientific Reports, demonstrating that it’s possible to use raisins to turn water into wine.

The authors harvested fresh grapes and dried them for 28 days. Some were dried using an incubator, some were sun-dried, and a third batch was dried using a combination of the two methods. The researchers then added the resulting raisins to bottles of water—three samples for each type of drying process—sealed the bottles, and stored them at room temperature for two weeks. One incubator-dried sample and two combo samples successfully fermented, but all three of the sun-dried samples did so, and at higher ethanol concentrations. Future research will focus on identifying the underlying molecular mechanisms. And for those interested in trying this at home, the authors warn that it only works with naturally sun-dried raisins, since store-bought varieties have oil coatings that block fermentation.

DOI: Scientific Reports, 2025. 10.1038/s41598-025-23715-3 (About DOIs).

An octopus-inspired pigment

An octopus camouflages itself with the seafloor. — Credit: Charlotte Seid

Octopuses, cuttlefish, and several other cephalopods can rapidly shift the colors in their skin thanks to that skin’s unique complex structure, including layers of chromatophores, iridophores, and leucophores. A color-shifting natural pigment called xanthommatin also plays a key role, but it’s been difficult to study because it’s hard to harvest enough directly from animals, and lab-based methods of making the pigment are labor-intensive and don’t yield much. Scientists at the University of San Diego have developed a new method for making xanthommatin in substantially larger quantities, according to a paper published in Nature Biotechnology.

The issue is that trying to get microbes to make foreign compounds creates a metabolic burden, and the microbes hence resist the process, hindering yields. The USD team figured out how to trick the cells into producing more xanthommatin by genetically engineering them in such a way that making the pigment was essential to a cell’s survival. They achieved yields of between 1 and 3 grams per liter, compared to just five milligrams of pigment per liter using traditional approaches. While this work is proof of principle, the authors foresee such future applications as photoelectronic devices and thermal coatings, dyes, natural sunscreens, color-changing paints, and environmental sensors. It could also be used to make other kinds of chemicals and help industries shift away from older methods that rely on fossil fuel-based materials.

DOI: Nature Biotechnology, 2025. 10.1038/s41587-025-02867-7 (About DOIs).

A body-swap robot

Participant standing on body-swap balance robot — Credit: Sachi Wickramasinghe/UBC Media Relations

Among the most serious risks facing older adults is falling. According to the authors of a paper published in Science Robotics, standing upright requires the brain to coordinate signals from the eyes, inner ears, and feet to counter gravity, and there’s a natural lag in how fast this information travels back and forth between brain and muscles. Aging and certain diseases like diabetic neuropathy and multiple sclerosis can further delay that vital communication; the authors liken it to steering a car with a wheel that responds half a second late. And it’s a challenge to directly study the brain under such conditions.

That’s why researchers at the University of British Columbia built a large “body swap” robotic platform. Subjects stood on force plates attached to a motor-driven backboard to reproduce the physical forces at play when standing upright: gravity, inertia, and “viscosity,” which in this case describes the damping effect of muscles and joints that allow us to lean without falling. The platform is designed to subtly alter those forces and also add a 200-millisecond delay.

The authors tested 20 participants and found that lowering inertia and making the viscosity negative resulted in similar instability to that which resulted from a signal delay. They then brought in ten new subjects to study whether adjusting body mechanics could compensate for information delays. They found that adding inertia and viscosity could at least partially counter the instability that arose from signal delay—essentially giving the body a small mechanical boost to help the brain maintain balance. The eventual goal is to design wearables that offer gentle resistance when an older person starts to lose their balance, and/or help patients with MS, for example, adjust to slower signal feedback.

DOI: Science Robotics, 2025. 10.1126/scirobotics.adv0496 (About DOIs).

X community notes might actually work

cropped image of phone screen showing an X post with a community note underneath — Credit: Huaxia Rui

Earlier this year, Elon Musk claimed that X’s community notes feature needed tweaking because it was being gamed by “government & legacy media” to contradict Trump—despite vigorously defending the robustness of the feature against such manipulation in the past. A growing body of research seems to back Musk’s earlier stance.

For instance, last year Bloomberg pointed to several studies suggesting that crowdsourcing worked just as well as using professional fact-checkers when assessing the accuracy of news stories. The latest evidence that crowd-sourcing fact checks can be effective at curbing misinformation comes from a paper published in the journal Information Systems Research, which found that X posts with public corrections were 32 percent more likely to be deleted by authors.

Co-author Huaxia Rui of the University of Rochester pointed out that community notes must meet a threshold before they will appear publicly on posts, while those that do not remain hidden from public view. Seeing a prime opportunity in the arrangement, Rui et al. analyzed 264,600 X posts that had received at least one community note and compared those just above and just below that threshold. The posts were collected from two different periods: June through August 2024, right before the US presidential election (when misinformation typically surges), and the post-election period of January and February 2025.

The fact that roughly one-third of authors responded to public community notes by deleting the post suggests that the built-in dynamics of social media (e.g., status, visibility, peer feedback) might actually help improve the spread of misinformation as intended. The authors concluded that crowd-checking “strikes a balance between First Amendment rights and the urgent need to curb misinformation.” Letting AI write the community notes, however, is probably still a bad idea.

DOI: Information Systems Research, 2025. 10.1287/isre.2024.1609 (About DOIs).

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

Research roundup: 6 cool stories we almost missed Read More »

Why synthetic emerald-green pigments degrade over time

art conservation, chemistry, culture, pigments, Science / Kris Guyer / November 24, 2025

Perhaps most relevant to this current paper is a 2020 study in which scientists analyzed Munch’s The Scream, which was showing alarming signs of degradation. They concluded the damage was not the result of exposure to light, but humidity—specifically, from the breath of museum visitors, perhaps as they lean in to take a closer look at the master’s brushstrokes.

Let there be (X-ray) light

Co-author Letizia Monico during the experiments at the European Synchrotron. ESRF

Emerald-green pigments are particularly prone to degradation, so that’s the pigment the authors of this latest paper decided to analyze. “It was already known that emerald-green decays over time, but we wanted to understand exactly the role of light and humidity in this degradation,” said co-author Letizia Monico of the University of Perugia in Italy.

The first step was to collect emerald-green paint microsamples with a scalpel and stereomicroscope from an artwork of that period—in this case, The Intrigue (1890) by James Ensor, currently housed in the Royal Museum of Fine Arts, in Antwerp, Belgium. The team analyzed the untreated samples using Fourier transform infrared imaging, then embedded the samples in polyester resin for synchrotron radiation X-ray analysis. They conducted separate analyses on both commercial and historical samples of emerald-green pigment powders and paint tubes, including one from a museum collection of paint tubes used by Munch.

Next, the authors created their own paint mockups by mixing commercial emerald-green pigment powders and their lab-made powders with linseed oil, and then applied the concoctions to polycarbonate substrates. They also squeezed paint from the Munch paint tube onto a substrate. Once the mockups were dry, thin samples were sliced from each mockup and also analyzed with synchrotron radiation. Then the mockups were subjected to two aging protocols designed to determine the effects of UV light (to simulate indoor lighting) and humidity on the pigments.

The results: In the mockups, light and humidity trigger different degradation pathways in emerald-green paints. Humidity results in the formation of arsenolite, making the paint brittle and prone to flaking. Light dulls the color by causing trivalent arsenic already in the pigment to oxidize into pentavalent compounds, forming a thin white layer on the surface. Those findings are consistent with the analyzed samples taken from The Intrigue, confirming the degradation is due to photo-oxidation. Light, it turns out, is the greatest threat to that particular painting, and possibly other masterpieces from the same period.

Science Advances, 2025. DOI: 10.1126/sciadv.ady1807 (About DOIs).

Why synthetic emerald-green pigments degrade over time Read More »

Neural network finds an enzyme that can break down polyurethane

AI, biochemistry, Biology, chemistry, enzymes, neural networks, polymers, polyurethane, protein design, proteins, Science / Tim Belzer / October 31, 2025

You’ll often hear plastic pollution referred to as a problem. But the reality is that it’s multiple problems. Depending on the properties we need, we form plastics out of different polymers, each of which is held together by a distinct type of chemical bond. So the method we use to break down one type of polymer may be incompatible with the chemistry of another.

That problem is why, even though we’ve had success finding enzymes that break down common plastics like polyesters and PET, they’re only partial solutions to plastic waste. However, researchers aren’t sitting back and basking in the triumph of partial solutions, and they’ve now got very sophisticated protein design tools to help them out.

That’s the story behind a completely new enzyme that researchers developed to break down polyurethane, the polymer commonly used to make foam cushioning, among other things. The new enzyme is compatible with an industrial-style recycling process that breaks the polymer down into its basic building blocks, which can be used to form fresh polyurethane.

Breaking down polyurethane

Image of a set of chemical bonds. From left to right there is an X, then a single bond to an oxygen, then a single bond to an oxygen that's double-bonded to carbon, then a single bond to a nitrogen, then a single bond to another X. — The basics of the chemical bonds that link polyurethanes. The rest of the polymer is represented by X’s here.

The new paper that describes the development of this enzyme lays out the scale of the problem: In 2024, we made 22 million metric tons of polyurethane. The urethane bond that defines these involves a nitrogen bonded to a carbon that in turn is bonded to two oxygens, one of which links into the rest of the polymer. The rest of the polymer, linked by these bonds, can be fairly complex and often contains ringed structures related to benzene.

Digesting polyurethanes is challenging. Individual polymer chains are often extensively cross-linked, and the bulky structures can make it difficult for enzymes to get at the bonds they can digest. A chemical called diethylene glycol can partially break these molecules down, but only at elevated temperatures. And it leaves behind a complicated mess of chemicals that can’t be fed back into any useful reactions. Instead, it’s typically incinerated as hazardous waste.

Neural network finds an enzyme that can break down polyurethane Read More »

The chemistry behind that pricey cup of civet coffee

chemistry, coffee, Food science, kopi luwak, Science / Kris Guyer / October 29, 2025

A sampling of scat

Kopi luwak is quite popular, with well-established markets in several South and East Asian countries. Its popularity has risen in Europe and the US as well, and India has recently become an emerging new market. Since there haven’t been similar studies of the chemical properties of kopi luwak from the Indian subcontinent, the authors of this latest study decided to fill that scientific gap. They focused on civet coffee produced in Kodagu, which produces nearly 36 percent of India’s total coffee production.

The authors collected 68 fresh civet scat samples from five different sites in Kodagu during peak fruit harvesting in January of this year. Collectors wore gloves to avoid contamination of the samples. For comparative analysis, they also harvested several bunches of ripened Robusta coffee berries. They washed the scat samples to remove the feces and also removed any palm seeds or other elements to ensure only Robusta beans remained.

For the manually harvested berries, the authors removed the pulp after a natural fermentation process and then sun-dried the beans for seven days. They then removed the hulls of both scat-derived and manually harvested berries and dried the beans in an oven for two hours. None of the bean samples were roasted, since roasting might significantly alter the acidity and chemical composition of the samples. For the chemical analysis, 10 distinct samples (five from each site where berries were collected) were ground into powder and subjected to various tests.

The civet beans had higher fat levels, particularly those compounds known to influence aroma and flavor, such as caprylic acid and methyl esters—contributing to kopi luwak’s distinctive aroma and flavor—but lower levels of caffeine, protein, and acidity, which would reduce the bitterness. The lower acidity is likely due to the coffee berries being naturally fermented in the civets’ digestive tracts, and there is more to learn about the role the gut microbiome plays in all of this. There were also several volatile organic compounds, common to standard coffee, that were extremely low or absent entirely in the civet samples.

In short, the comparative analysis “further supports the notion that civet coffee is chemically different from conventionally produced coffee of similar types, mainly due to fermentation,” the authors concluded. They recommend further research using roasted samples, along with studying other coffee varieties, samples from a more diverse selection of farms, and the influence of certain ecological conditions, such as canopy cover and the presence of wild trees.

Scientific Reports, 2025. DOI: 10.1038/s41598-025-21545-x (About DOIs).

The chemistry behind that pricey cup of civet coffee Read More »

Breaking down rare earth element magnets for recycling

chemistry, rare earth elements, recycling, Science / Mike M. / October 20, 2025

All the world’s discarded phones, bricked laptops, and other trashed electronics are collectively a treasure trove of rare earth elements (REEs). But separating out and recovering these increasingly sought-after materials is no easy task.

However, a team of researchers says it has developed a way of separating REEs from waste—magnets, in this case—that is relatively easy, uses less energy, and isn’t nearly as emissions and pollution intensive as current methods. The team published a paper describing this method in the Proceedings of the National Academy of Sciences.

In short, this process involves using an electric current to heat waste magnets to very high temperatures very fast, and using chlorine gas to react with the non-REEs in the mix, keeping them in the vapor phase. James Tour, one of the authors and a professor of materials science and nanoengineering at Rice University, says that the research can help the United States meet its growing need for these elements.

“The country’s scurrying to try to see how we can get these [REEs],” he says. “And, in our argument, it’s all in our waste… We have it right here, just pull it right back out of the waste.”

Getting hot in here

In 2018, Tour and his colleagues discovered that this rapid heating process, called flash joule heating, can turn any carbon source—including coal, biochar, and mixed plastic—into graphene, a very thin, strong, and conductive material.

Building on this, in 2023, they developed a method that uses flash joule heating and chlorine. In this work, they identified the Gibbs free energy, the reactivity of a material, for the oxide form of all 17 REEs and nine common oxides found in REE waste.

Ground-up waste magnets are put on a platform made of carbon and surrounded by a glass chamber. A current runs through the platform, rapidly producing immense heat, thousands of degrees celsius in a matter of seconds. Chlorine gas is then released into the chamber, creating chlorides of unwanted elements like iron and lowering their boiling points.

Breaking down rare earth element magnets for recycling Read More »

Chemistry Nobel prize awarded for building ordered polymers with metal

chemistry, chemistry Nobel, metal organic framework, nobel prizes, Science / Rejus Almole / October 8, 2025

Unlike traditional polymers, this structure allows MOFs to have open internal spaces with a well-defined size, which can allow some molecules to pass through while filtering out others. In addition, the presence of metals provides for interesting chemistry. The metals can serve as catalysts or preferentially bind to one molecule within a mixture.

Knowing what we know now, it all seems kind of obvious that this would work. But when Robson started his work at the University of Melbourne, the few people who thought about the issue at all expected that the molecules he was building would be unstable and collapse.

The first MOF Robson built used copper as its metal of choice. It was linked to an organic molecule that retained its rigid structure through the presence of a benzene ring, which doesn’t bend. Both the organic molecule and the copper could form four different bonds, allowing the structure to grow by doing the rough equivalent of stacking a bunch of three-sided pyramids—a conscious choice by Robson.

Image of multiple triangular chemicals stacked on top of each other, forming a structure with lots of open internal spaces. — The world’s first MOF, synthesized by Robson and his colleagues. Credit: Johan Jarnestad/The Royal Swedish Academy of Sciences

In this case, however, the internal cavities remained filled by the solvent in which the MOF was formed. But the solvent could move freely through the material. Still, based on this example, Robson predicted many of the properties that have since been engineered into different MOFs: the ability to retain their structure even after solvents are removed, the presence of catalytic sites, and the ability of MOFs to act as filters.

Expanding the concept

All of that might seem a very optimistic take for someone’s first effort. But the measure of Robson’s success is that he convinced other chemists of the potential. One was Susumu Kitagawa of Kyoto University. Kitagawa and his collaborators built a MOF that had large internal channels that extended the entire length of the material. Made in a watery solution, the MOF could be dried out and have gas flow through it, with the structure retaining molecules like oxygen, nitrogen, and methane.

Chemistry Nobel prize awarded for building ordered polymers with metal Read More »

Betel nuts have been giving people a buzz for over 4,000 years

Archeology, betel nuts, Biology, chemistry, drugs, Science, stimulants / Rejus Almole / August 20, 2025

Ancient rituals and customs often leave behind obvious archaeological evidence. From the impeccably preserved mummies of Egypt to psychoactive substance residue that remained at the bottom of a clay vessel for thousands of years, it seems as if some remnants of the past, even if not all are immediately visible, have defied the ravages of time.

Chewing betel nuts is a cultural practice in parts of Southeast Asia. When chewed, these reddish nuts, which are the fruit of the areca palm, release psychoactive compounds that heighten alertness and energy, promote feelings of euphoria, and help with relaxation. They are usually wrapped in betel leaves with lime paste made from powdered shells or corals, depending on the region.

Critically, the ancient teeth from betel nut chewers are distinguishable because of red staining. So when archaeologist Piyawit Moonkham, of Chiang Mai University in Thailand, unearthed 4,000-year-old skeletons from the Bronze Age burial site of Nong Ratchawat, the lack of telltale red stains appeared to indicate that the individuals they belonged to were not chewers of betel nuts.

Yet when he sampled plaque from the teeth, he found that several of the teeth from one individual contained compounds found in betel nuts. This invisible evidence could indicate teeth cleaning practices had gotten rid of the color or that there were alternate methods of consumption.

“We found that these mineralized plaque deposits preserve multiple microscopic and biomolecular indicators,” Moonkham said in a study recently published in Frontiers. “This initial research suggested the detection potential for other psychoactive plant compounds.”

Since time immemorial

Betel nut chewing has been practiced in Thailand for at least 9,000 years. During the Lanna Kingdom, which began in the 13th century, teeth stained from betel chewing were considered a sign of beauty. While the practice is fading, it is still a part of some religious ceremonies, traditional medicine, and recreational gatherings, especially among certain ethnic minorities and people living in rural areas.

Betel nuts have been giving people a buzz for over 4,000 years Read More »

This aerogel and some sun could make saltwater drinkable

aerogel, chemistry, desalina, desalination, materials science, Science, solar power / Rejus Almole / July 26, 2025

Earth is about 71 percent water. An overwhelming 97 percent of that water is found in the oceans, leaving us with only 3 percent in the form of freshwater—and much of that is frozen in the form of glaciers. That leaves just 0.3 percent of that freshwater on the surface in lakes, swamps, springs, and our main sources of drinking water, rivers and streams.

Despite our planet’s famously blue appearance from space, thirsty aliens would be disappointed. Drinkable water is actually pretty scarce.

As if that doesn’t already sound unsettling, what little water we have is also threatened by climate change, urbanization, pollution, and a global population that continues to expand. Over 2 billion people live in regions where their only source of drinking water is contaminated. Pathogenic microbes in the water can cause cholera, diarrhea, dysentery, polio, and typhoid, which could be fatal in areas without access to vaccines or medical treatment.

Desalination of seawater is a possible solution, and one approach involves porous materials absorbing water that evaporates when heated by solar energy. The problem with most existing solar-powered evaporators is that they are difficult to scale up for larger populations. Performance decreases with size, because less water vapor can escape from materials with tiny pores and thick boundaries—but there is a way to overcome this.

Feeling salty

Researcher Xi Shen of the Hong Kong Polytechnic University wanted to figure out a way to improve these types of systems. He and his team have now created an aerogel that is far more efficient at turning over fresh water than previous methods of desalination.

“The key factors determining the evaporation performance of porous evaporators include heat localization, water transport, and vapor transport,” Shen said in a study recently published in ACS Energy Letters. “Significant advancements have been made in the structural design of evaporators to realize highly efficient thermal localization and water transport.”

Solar radiation is the only energy used to evaporate the water, which is why many attempts have been made to develop what are called photothermal materials. When sunlight hits these types of materials, they absorb light and convert it into heat energy, which can be used to speed up evaporation. Photothermal materials can be made of substances including polymers, metals, alloys, ceramics, or cements. Hydrogels have been used to successfully decontaminate and desalinate water before, but they are polymers designed to retain water, which negatively affects efficiency and stability, as opposed to aerogels, which are made of polymers that hold air. This is why Shen and his team decided to create a photothermal aerogel.

This aerogel and some sun could make saltwater drinkable Read More »

Rice could be key to brewing better non-alcoholic beer

beer, chemistry, fermentation, Science / Tim Belzer / July 3, 2025

small glass of light colored beer with a nice foam head — Rice enhances flavor profiles for nonalcoholic beer, reduces fermentation time, and may contribute to flavor stability. Credit: Paden Johnson/CC BY-NC-SA

He and his team—including Christian Schubert, a visiting postdoc from the Research Institute for Raw Materials and Beverage Analysis in Berlin—brewed their own non-alcoholic beers, ranging from those made with 100 percent barley malt to ones made with 100 percent rice. They conducted a volatile chemical analysis to identify specific compounds present in the beers and assembled two sensory panels of tasters (one in the US, one in Europe) to assess aromas, flavors, and mouthfeel.

The panelists determined the rice-brewed beers had less worty flavors, and the chemical analysis revealed why: lower levels of aldehyde compounds. Instead, other sensory attributes emerged, most notably vanilla or buttery notes. “If a brewer wanted a more neutral character, they could use nonaromatic rice,” the authors wrote. Along with brewing beers with 50 percent barley/50 percent rice, this would produce non-alcoholic beers likely to appeal more broadly to consumers.

The panelists also noted that higher rice content resulted in beers with a fatty/creamy mouthfeel—likely because higher rice content was correlated with increased levels of larger alcohol molecules, which are known to contribute to a pleasant mouthfeel. But it didn’t raise the alcohol content above the legal threshold for a nonalcoholic beer.

There were cultural preferences, however. The US panelists didn’t mind worty flavors as much as the European tasters did, which might explain why the former chose beers brewed with 70 percent barley/30 percent rice as the optimal mix. Their European counterparts preferred the opposite ratio (30 percent barley/70 percent rice). The explanation “may lie in the sensory expectations shaped by each region’s brewing traditions,” the authors wrote. Fermentation also occurred more quickly as the rice content increased because of higher levels of glucose and fructose.

The second study focused on testing 74 different rice cultivars to determine their extract yields, an important variable when it comes to an efficient brewing process, since higher yields mean brewers can use less grain, thereby cutting costs. This revealed that cultivars with lower amylose content cracked more easily to release sugars during the mashing process, producing the highest yields. And certain varieties also had lower gelatinization temperatures for greater ease of processing.

International Journal of Food Science, 2025. DOI: 10.1080/10942912.2025.2520907 (About DOIs)

Journal of the American Society of Brewing Chemists, 2025. DOI: 10.1080/03610470.2025.2499768

Rice could be key to brewing better non-alcoholic beer Read More »

New material may help us build Predator-style thermal vision specs

chemistry, infrared sensor, materials science, Night Vision, Science / Tim Belzer / May 2, 2025

One way to do that is called remote epitaxy, where an intermediate layer made out of graphene or other material is introduced between the substrate and the growing crystals. Once the epitaxy process is done, the substrate and everything on it are soaked in a chemical solution that dissolves this intermediate layer, leaving the crystalline film intact. This works but is expensive, difficult to scale, and takes a lot of time. To make the process cheaper and faster, the MIT team had to grow the crystals directly on the substrate, without any intermediate layers. What they were trying to achieve was a non-stick frying pan effect but at an atomically small scale.

Weakening the bonds

The material that prevented the crystalline films from sticking to substrates wasn’t Teflon but lead. When the team was experimenting with growing different films in their previous studies, they noticed that there was a material that easily came off the substrate, yet retained an atomically smooth surface: PMN-PT, or lead magnesium niobate-lead titanate.

The lead atoms in the PMN-PT weakened the covalent bonds between the film and the substrate, preventing the electrons from jumping through the interface between the two materials. “We just had to exert a bit of stress to induce a crack at the interface between the film and the substrate and we could realize the liftoff,” Zhang told Ars. “Very simple—we could remove these films within a second.”

But PMN-PT, besides its inherent non-stickiness, had more tricks up its sleeves; it had exceptional pyroelectric properties. Once the team realized they could manufacture and peel away PMN-PT films at will, they tried something a bit more complex: a cooling-free, far-infrared radiation detector. “We were trying to achieve performance comparable with cooled detectors,” Zhang says.

The detector they constructed was made from 100 pieces of 10-nanometer-thin PMN-PT films, each about 60 square microns, that the team transferred onto a silicon chip. This produced a 100-pixel infrared sensor. Tests with ever smaller changes in temperature indicated that it outperformed state-of-the art night vision systems and was sensitive to radiation across the entire infrared spectrum. (Mercury cadmium telluride detectors respond to a much narrower band of wavelengths.)

New material may help us build Predator-style thermal vision specs Read More »

Scientists made a stretchable lithium battery you can bend, cut, or stab

aeorogels, batteries, chemistry, electrolytes, materials science, Science / Mike M. / April 15, 2025

The Li-ion batteries that power everything from smartphones to electric cars are usually packed in rigid, sealed enclosures that prevent stresses from damaging their components and keep air from coming into contact with their flammable and toxic electrolytes. It’s hard to use batteries like this in soft robots or wearables, so a team of scientists at the University California, Berkeley built a flexible, non-toxic, jelly-like battery that could survive bending, twisting, and even cutting with a razor.

While flexible batteries using hydrogel electrolytes have been achieved before, they came with significant drawbacks. “All such batteries could [only] operate [for] a short time, sometimes a few hours, sometimes a few days,” says Liwei Lin, a mechanical engineering professor at UC Berkeley and senior author of the study. The battery built by his team endured 500 complete charge cycles—about as many as the batteries in most smartphones are designed for.

Power in water

“Current-day batteries require a rigid package because the electrolyte they use is explosive, and one of the things we wanted to make was a battery that would be safe to operate without this rigid package,” Lin told Ars. Unfortunately, flexible packaging made of polymers or other stretchable materials can be easily penetrated by air or water, which will react with standard electrolytes, generating lots of heat, potentially resulting in fires and explosions. This is why, in 2017, scientists started to experiment with quasi-solid-state hydrogel electrolytes.

These hydrogels were made of a polymer net that gave them their shape, crosslinkers like borax or hydrogen bonds that held this net together, a liquid phase made of water, and salt or other electrolyte additives providing ions that moved through the watery gel as the battery charged or discharged.

But hydrogels like that had their own fair share of issues. The first was a fairly narrow electrochemical stability window—a safe zone of voltage the battery can be exposed to. “This really limits how much voltage your battery can output,” says Peisheng He, a researcher at UC Berkeley Sensor and Actuator Center and lead author of the study. “Nowadays, batteries usually operate at 3.3 volts, so their stability window must be higher than that, probably four volts, something like that.” Water, which was the basis of these hydrogel electrolytes, typically broke down into hydrogen and oxygen when exposed to around 1.2 volts. That problem was solved by using highly concentrated salt water loaded with highly fluorinated lithium salts, which made it less likely to break down. But this led the researchers straight into safety issues, as fluorinated lithium salts are highly toxic to humans.

Scientists made a stretchable lithium battery you can bend, cut, or stab Read More »

A guide to the “platonic ideal” of a Negroni and other handy tips

aromas, chemistry, cocktails, mixology, molecular mixology, perfumery, Science, smell, taste perception / Paul Patrick / April 12, 2025

Perfumer by day, mixologist by night, Kevin Peterson specializes in crafting scent-paired cocktails.

Kevin Peterson is a “nose” for his own perfume company, Sfumato Fragrances, by day. By night, Sfumato’s retail store in Detroit transforms into Peterson’s craft cocktail bar, Castalia, where he is chief mixologist and designs drinks that pair with carefully selected aromas. He’s also the author of Cocktail Theory: A Sensory Approach to Transcendent Drinks, which grew out of his many (many!) mixology experiments and popular YouTube series, Objective Proof: The Science of Cocktails.

It’s fair to say that Peterson has had an unusual career trajectory. He worked as a line cook and an auto mechanic, and he worked on the production line of a butter factory, among other gigs, before attending culinary school in hopes of becoming a chef. However, he soon realized it wasn’t really what he wanted out of life and went to college, earning an undergraduate degree in physics from Carleton College and a PhD in mechanical engineering from the University of Michigan.

After 10 years as an engineer, he switched focus again and became more serious about his side hobby, perfumery. “Not being in kitchens anymore, I thought—this is a way to keep that little flavor part of my brain engaged,” Peterson told Ars. “I was doing problem sets all day. It was my escape to the sensory realm. ‘OK, my brain is melting—I need a completely different thing to do. Let me go smell smells, escape to my little scent desk.'” He and his wife, Jane Larson, founded Sfumato, which led to opening Castalia, and Peterson finally found his true calling.

Peterson spent years conducting mixology experiments to gather empirical data about the interplay between scent and flavor, correct ratios of ingredients, temperature, and dilution for all the classic cocktails—seeking a “Platonic ideal,” for each, if you will. He supplemented this with customer feedback data from the drinks served at Castalia. All that culminated in Cocktail Theory, which delves into the chemistry of scent and taste, introducing readers to flavor profiles, textures, visual presentation, and other factors that contribute to one’s enjoyment (or lack thereof) of a cocktail. And yes, there are practical tips for building your own home bar, as well as recipes for many of Castalia’s signature drinks.

In essence, Peterson’s work adds scientific rigor to what is frequently called the “Mr. Potato Head” theory of cocktails, a phrase coined by the folks at Death & Company, who operate several craft cocktail bars in key cities. “Let’s say you’ve got some classic cocktail, a daiquiri, that has this many parts of rum, this many parts of lime, this many parts of sugar,” said Peterson, who admits to having a Mr. Potato Head doll sitting on Castalia’s back bar in honor of the sobriquet. “You can think about each ingredient in a more general way: instead of rum, this is the spirit; instead of lime, this is the citrus; sugars are sweetener. Now you can start to replace those things with other things in the same categories.”

We caught up with Peterson to learn more.

Ars Technica: How did you start thinking about the interplay between perfumery and cocktail design and the role that aroma plays in each?

Kevin Peterson: The first step was from food over to perfumery, where I think about building a flavor for a soup, for a sauce, for a curry, in a certain way. “Oh, there’s a gap here that needs to be filled in by some herbs, some spice.” It’s almost an intuitive kind of thing. When I was making scents, I had those same ideas: “OK, the shape of this isn’t quite right. I need this to roughen it up or to smooth out this edge.”

Then I did the same thing for cocktails and realized that those two worlds didn’t really talk to each other. You’ve got two groups of people that study all the sensory elements and how to create the most intriguing sensory impression, but they use different language; they use different toolkits. They’re going for almost the same thing, but there was very little overlap between the two. So I made that my niche: What can perfumery teach bartenders? What can the cocktail world teach perfumery?

Ars Technica: In perfumery you talk about a top, a middle, and a base note. There must be an equivalent in cocktail theory?

Kevin Peterson: In perfumery, that is mostly talking about the time element: top notes perceived first, then middle notes, then base notes as you wear it over the course of a few hours. In the cocktail realm, there is that time element as well. You get some impression when you bring the glass to your nose, something when you sip, something in the aftertaste. But there can also be a spatial element. Some things you feel right at the tip of your tongue, some things you feel in different parts of your face and head, whether that’s a literal impression or you just kind of feel it somewhere where there’s not a literal nerve ending. It’s about filling up that space, or not filling it up, depending on what impression you’re going for—building out the full sensory space.

Ars Technica: You also talk about motifs and supportive effects or ornamental flourishes: themes that you can build on in cocktails.

Kevin Peterson: Something I see in the cocktail world occasionally is that people just put a bunch of ingredients together and figure, “This tastes fine.” But what were you going for here? There are 17 things in here, and it just kind of tastes like you were finger painting: “Hey, I made brown.” Brown is nice. But the motifs that I think about—maybe there’s just one particular element that I want to highlight. Say I’ve got this really great jasmine essence. Everything else in the blend is just there to highlight the jasmine.

If you’re dealing with a really nice mezcal or bourbon or some unique herb or spice, that’s going to be the centerpiece. You’re not trying to get overpowered by some smoky scotch, by some other more intense ingredient. The motif could just be a harmonious combination of elements. I think the perfect old-fashioned is where everything is present and nothing’s dominating. It’s not like the bitters or the whiskey totally took over. There’s the bitters, there’s a little bit of sugar, there’s the spirit. Everything’s playing nicely.

Another motif, I call it a jazz note. A Sazerac is almost the same as an old-fashioned, but it’s got a little bit of absinthe in it. You get all the harmony of the old-fashioned, but then you’re like, “Wait, what’s this weird thing pulling me off to the side? Oh, this absinthe note is kind of separate from everything else that’s going on in the drink.” It’s almost like that tension in a musical composition: “Well, these notes sound nice, but then there’s one that’s just weird.” But that’s what makes it interesting, that weird note. For me, formalizing some of those motifs help me make it clearer. Even if I don’t tell that to the guest during the composition stage, I know this is the effect I’m going for. It helps me build more intentionally when I’ve got a motif in mind.

Ars Technica: I tend to think about cocktails more in terms of chemistry, but there are many elements to taste and perception and flavor. You talk about ingredient matching, molecular matching, and impression matching, i.e., how certain elements will overlap in the brain. What role do each of those play?

Kevin Peterson: A lot of those ideas relate to how we pair scents with cocktails. At my perfume company, we make eight fragrances as our main line. Each scent then gets a paired drink on the cocktail menu. For example, this scent has coriander, cardamom, and nutmeg. What does it mean that the drink is paired with that? Does it need to literally have coriander, cardamom, and nutmeg in it? Does it need to have every ingredient? If the scent has 15 things, do I need to hit every note?

chart with sad neutral and happy faces showing the optimal temperature and dilution for a dauquiri — Peterson made over 100 daiquiris to find the “Platonic ideal” of the classic cocktail Credit: Kevin Peterson

The literal matching is the most obvious. “This has cardamom, that has cardamom.” I can see how that pairs. The molecular matching is essentially just one more step removed: Rosemary has alpha-pinene in it, and juniper berries have alpha-pinene in them. So if the scent has rosemary and the cocktail has gin, they’re both sharing that same molecule, so it’s still exciting that same scent receptor. What I’m thinking about is kind of resonant effects. You’re approaching the same receptor or the same neural structure in two different ways, and you’re creating a bigger peak with that.

The most hand-wavy one to me is the impression matching. Rosemary smells cold, and Fernet-Branca tastes cold even when it’s room temperature. If the scent has rosemary, is Fernet now a good match for that? Some of the neuroscience stuff that I’ve read has indicated that these more abstract ideas are represented by the same sort of neural-firing patterns. Initially, I was hesitant; cold and cold, it doesn’t feel as fulfilling to me. But then I did some more reading and realized there’s some science behind it and have been more intrigued by that lately.

Ars Technica: You do come up with some surprising flavor combinations, like a drink that combined blueberry and horseradish, which frankly sounds horrifying.

Kevin Peterson: It was a hit on the menu. I would often give people a little taste of the blueberry and then a little taste of the horseradish tincture, and they’d say, “Yeah, I don’t like this.” And then I’d serve them the cocktail, and they’d be like, “Oh my gosh, it actually worked. I can’t believe it.” Part of the beauty is you take a bunch of things that are at least not good and maybe downright terrible on their own, and then you stir them all together and somehow it’s lovely. That’s basically alchemy right there.

Ars Technica: Harmony between scent and the cocktail is one thing, but you also talk about constructive interference to get a surprising, unexpected, and yet still pleasurable result.

Kevin Peterson: The opposite is destructive interference, where there’s just too much going on. When I’m coming up with a drink, sometimes that’ll happen, where I’m adding more, but the flavor impression is going down. It’s sort of a weird non-linearity of flavor, where sometimes two plus two equals four, sometimes it equals three, sometimes it equals 17. I now have intuition about that, having been in this world for a lot of years, but I still get surprised sometimes when I put a couple things together.

Often with my end-of-the-shift drink, I’ll think, “Oh, we got this new bottle in. I’m going to try that in a Negroni variation.” Then I lose track and finish mopping, and then I sip, and I’m like, “What? Oh my gosh, I did not see this coming at all.” That little spark, or whatever combo creates that, will then often be the first step on some new cocktail development journey.

man's torso in a long-sleeved button down white shirt, with a small glass filled with juniper berries in front of him — Pairing scents with cocktails involves experimenting with many different ingredients Credit: EE Berger

Ars Technica: Smoked cocktails are a huge trend right now. What’s the best way to get a consistently good smoky element?

Kevin Peterson: Smoke is tricky to make repeatable. How many parts per million of smoke are you getting in the cocktail? You could standardize the amount of time that it’s in the box [filled with smoke]. Or you could always burn, say, exactly three grams of hickory or whatever. One thing that I found, because I was writing the book while still running the bar: People have a lot of expectations around how the drink is going to be served. Big ice cubes are not ideal for serving drinks, but people want a big ice cube in their old-fashioned. So we’re still using big ice cubes. There might be a Platonic ideal in terms of temperature, dilution, etc., but maybe it’s not the ideal in terms of visuals or tactile feel, and that is a part of the experience.

With the smoker, you open the doors, smoke billows out, your drink emerges from the smoke, and people say, “Wow, this is great.” So whether you get 100 PPM one time and 220 PPM the next, maybe that gets outweighed by the awesomeness of the presentation. If I’m trying to be very dialed in about it, I’ll either use a commercial smoky spirit—Laphroaig scotch, a smoky mezcal—where I decide that a quarter ounce is the amount of smokiness that I want in the drink. I can just pour the smoke instead of having to burn and time it.

Or I might even make my own smoke: light something on fire and then hold it under a bottle, tip it back up, put some vodka or something in there, shake it up. Now I’ve got smoke particles in my vodka. Maybe I can say, “OK, it’s always going to be one milliliter,” but then you miss out on the presentation—the showmanship, the human interaction, the garnish. I rarely garnish my own drinks, but I rarely send a drink out to a guest ungarnished, even if it’s just a simple orange peel.

Ars Technica: There’s always going to be an element of subjectivity, particularly when it comes to our sensory perceptions. Sometimes you run into a person who just can’t appreciate a certain note.

Kevin Peterson: That was something I grappled with. On the one hand, we’re all kind of living in our own flavor world. Some people are more sensitive to bitter. Different scent receptors are present in different people. It’s tempting to just say, “Well, everything’s so unique. Maybe we just can’t say anything about it at all.” But that’s not helpful either. Somehow, we keep having delicious food and drink and scents that come our way.

A sample page from Cocktail Theory discussing temperature and dilution — A sample page from *Cocktail Theory* discussing temperature and dilution. Credit: EE Berger

I’ve been taking a lot of survey data in my bar more recently, and definitely the individuality of preference has shown through in the surveys. But another thing that has shown through is that there are some universal trends. There are certain categories. There’s the spirit-forward, bittersweet drinkers, there’s the bubbly citrus folks, there’s the texture folks who like vodka soda. What is the taste? What is the aroma? It’s very minimal, but it’s a very intense texture. Having some awareness of that is critical when you’re making drinks.

One of the things I was going for in my book was to find, for example, the platonically ideal gin and tonic. What are the ratios? What is the temperature? How much dilution to how much spirit is the perfect amount? But if you don’t like gin and tonics, it doesn’t matter if it’s a platonically ideal gin and tonic. So that’s my next project. It’s not just getting the drink right. How do you match that to the right person? What questions do I have to ask you, or do I have to give you taste tests? How do I draw that information out of the customer to determine the perfect drink for them?

We offer a tasting menu, so our full menu is eight drinks, and you get a mini version of each drink. I started giving people surveys when they would do the tasting menu, asking, “Which drink do you think you like the most? Which drink do you think you like the least?” I would have them rate it. Less than half of people predicted their most liked and least liked, meaning if you were just going to order one drink off the menu, your odds are less than a coin flip that you would get the right drink.

Ars Technica: How does all this tie into your “cocktails as storytelling” philosophy?

Kevin Peterson: So much of flavor impression is non-verbal. Scent is very hard to describe. You can maybe describe taste, but we only have five-ish words, things like bitter, sour, salty, sweet. There’s not a whole lot to say about that: “Oh, it was perfectly balanced.” So at my bar, when we design menus, we’ll put the drinks together, but then we’ll always give the menu a theme. The last menu that we did was the scientist menu, where every drink was made in honor of some scientist who didn’t get the credit they were due in the time they were alive.

Having that narrative element, I think, helps people remember the drink better. It helps them in the moment to latch onto something that they can more firmly think about. There’s a conceptual element. If I’m just doing chores around the house, I drink a beer, it doesn’t need to have a conceptual element. If I’m going out and spending money and it’s my night and I want this to be a more elevated experience, having that conceptual tie-in is an important part of that.

two martini glasses side by side with a cloudy liquid in them a bright red cherry at the bottom of the glass — My personal favorite drink, Corpse Reviver No. 2, has just a hint of absinthe. Credit: Sean Carroll

Ars Technica: Do you have any simple tips for people who are interested in taking their cocktail game to the next level?

Kevin Peterson: Old-fashioneds are the most fragile cocktail. You have to get all the ratios exactly right. Everything has to be perfect for an old-fashioned to work. Anecdotally, I’ve gotten a lot of old-fashioneds that were terrible out on the town. In contrast, the Negroni is the most robust drink. You can miss the ratios. It’s got a very wide temperature and dilution window where it’s still totally fine. I kind of thought of them in the same way prior to doing the test. Then I found that this band of acceptability is much bigger for the Negroni. So now I think of old-fashioneds as something that either I make myself or I order when I either trust the bartender or I’m testing someone who wants to come work for me.

My other general piece of advice: It can be a very daunting world to try to get into. You may say, “Oh, there’s all these classics that I’m going to have to memorize, and I’ve got to buy all these weird bottles.” My advice is to pick a drink you like and take baby steps away from that drink. Say you like Negronis. That’s three bottles: vermouth, Campari, and gin. Start with that. When you finish that bottle of gin, buy a different type of gin. When you finish the Campari, try a different bittersweet liqueur. See if that’s going to work. You don’t have to drop hundreds of dollars, thousands of dollars, to build out a back bar. You can do it with baby steps.

A guide to the “platonic ideal” of a Negroni and other handy tips Read More »