Latest news with #Francl
The Star
03-07-2025
- Health
- The Star
An expert chemist's guide to brewing the perfect cup of tea
When it comes to crafting the perfect cup of tea, lovers of the brew know it's as much about flavour and ritual as it is about comfort and connection. From black to green, oolong to herbal, every cup tells a story. But what if we told you that behind the soothing steam and fragrant leaves lies a world of chemistry – one that can actually help you brew a better, more flavourful cup? According to Michelle Francl, professor of chemistry at Bryn Mawr College in Pennsylvania, USA and author of Steeped: The Chemistry of Tea , brewing tea is a rich chemical process involving hundreds of compounds that influence the colour, aroma, taste and even health benefits of every cup. 'Tea is the world's most popular beverage. What many people don't realise is how complex the chemistry behind it truly is,' she said. While most South Africans reach for red Rooibos, the green, unfermented version actually has higher antioxidant levels. 'Fermented Rooibos has fewer antioxidants, because the fermentation process is essentially an oxidation process. Antioxidants act like little sponges soaking up oxygen. Once they've reacted, they can't function as antioxidants anymore,' Francl,added. Green Rooibos retains more aspalathin, a rare and potent antioxidant unique to the plant, but one that degrades with time and oxygen. Her advice? 'Drink it fresh.' Francl also cautions against using mineral-heavy water. In teas made from Camellia sinensis, it can result in 'tea scum' – a layer of compounds floating on top of your brew. She suspects something similar may occur with Rooibos if the water is particularly hard. 'These mineral-polyphenol interactions can dull flavour, while filtered water can help preserve the taste profile.' Many Rooibos drinkers report that longer steeping enhances sweetness. Though there's no formal analysis to confirm this, Francl says it's plausible. 'Longer steep times increase the presence of maltol, a natural flavour enhancer and vanillin, the same compound that gives vanilla its signature sweetness.' To brew the ultimate cup of Rooibos, Francl recommends the following: Use green Rooibos if your goal is to maximise antioxidant intake Choose fresh Rooibos to retain aspalathin content Use boiling water (100°C) Steep for 10 minutes If possible, opt for filtered water to avoid flavour-dulling minerals Whether you're sipping Rooibos to unwind after a long day or seeking its health benefits, knowing the science behind the steep can elevate your tea ritual. As Francl so elegantly puts it, 'Brewing tea is not just an art. It's a beautifully balanced act of chemistry.' So next time you brew a cup, give it the full ten minutes and let science do the rest.
The Citizen
03-07-2025
- General
- The Citizen
Expert tips: How to brew the perfect cup of tea this winter
According to Professor Michelle Francl, making a great cup of tea is more than just boiling water and adding a teabag. As winter tightens its grip on South Africa, there's nothing more comforting than a hot cup of tea. However, according to Michelle Francl, a chemistry professor and author of Steeped: The Chemistry of Tea, making a great brew is more than just boiling water and adding a teabag. It's a chemical process that can be fine-tuned for flavour, aroma, colour, and health benefits. 'Tea is the world's most popular beverage, but few people realise just how complex its chemistry really is,' she said. Francl explains that tea contains hundreds of compounds that affect its taste and aroma. Steeping time, water temperature, and even the type of water used can all influence the chemical make-up of your brew. 'The longer you let anything steep, the more compounds will be extracted. Lighter, more water-soluble molecules come out first. Over time, larger polyphenols are drawn into the infusion, building a more complex flavour, but also increasing astringency,' she says. She notes that for black and green teas, getting the timing right is essential to balancing flavour and mouthfeel. 'Water temperature also plays a role. Lower temperatures preserve delicate compounds, while boiling water helps extract more antioxidants in certain herbal teas.' While Francl's book explores teas made from the Camellia sinensis plant – including black, green, white, and oolong teas – she also shares insights into South Africa's beloved Rooibos, which comes from a different plant altogether (Aspalathus linearis). She adds that while most people reach for red Rooibos, the green, unfermented version has higher antioxidant levels. 'Fermented Rooibos has fewer antioxidants because the fermentation process is essentially an oxidation process. Antioxidants act like little sponges, soaking up oxygen. Once they've reacted, they can't function as antioxidants anymore.' ALSO READ: Matcha: The Japanese tea, taking over the world and Mzansi Brewing the perfect cup of tea Use boiling water (100°C) : This is especially important for black and Rooibos teas, which benefit from high temperatures to release their full flavour and antioxidant content. : This is especially important for black and Rooibos teas, which benefit from high temperatures to release their full flavour and antioxidant content. Steep for 10 minutes : A longer steep ensures more compounds are extracted, resulting in a richer, fuller taste. : A longer steep ensures more compounds are extracted, resulting in a richer, fuller taste. Choose fresh leaves when possible : Loose-leaf tea offers better quality and flavour than many commercial teabags. : Loose-leaf tea offers better quality and flavour than many commercial teabags. Use filtered water: Minerals in tap water can interfere with the tea's delicate chemistry and alter the taste. NOW READ: Recipe of the day: Mushroom, biltong and potato chowder makes perfect winter warmer dish
Yahoo
01-05-2025
- Health
- Yahoo
Where does vanilla flavoring come from? Probably not beaver butts.
Are there beaver secretions in your vanilla ice cream? News articles or food influencers on social media might have you believe that castoreum, a yellow, syrupy substance from the castor sacs near a beaver's anus, is used as everyday vanilla flavoring, disguised as 'natural.' According to some of these sources, beaver castor is an ingredient in everything from vanilla ice cream to strawberry-flavored oatmeal. But experts say this couldn't be further from the truth. While people have used castoreum for medicinal purposes and, yes, to flavor perfumes and foods since ancient times, there's almost nothing in the grocery store today that contains castoreum. 'It turns out that the stuff is incredibly expensive, because it's rare; there's no way it's in your ice cream,' says Michelle Francl, a chemist at Bryn Mawr College who studies the science of food. According to Francl, in 2020 about 16 million pounds of vanilla extract —collected from vanilla orchids, a large group of flowering plants—was produced worldwide, according to the Food and Agriculture Organization. That said, castoreum still exists in niche products such as bäversnaps, a Swedish liquor, according to the 2022 book Beavers: Ecology, Behaviour, Conservation, and Management by Frank Rosell and Róisín Campbell-Palmer. In total, the U.S. consumes less than 292 pounds a year of castoreum, castoreum extract, and castoreum liquid, according to the latest edition of Fenaroli's Handbook of Flavor Ingredients. To harvest castoreum, trappers kill beavers and remove their castor glands, which are dried and crushed. They then use alcohol to extract castoreum, similar to how vanilla is removed from the plant to make your vanilla ice cream, Francl says. Read more about the history of vanilla. For over 2,000 years, people have turned to castoreum to cure all sorts of maladies, including fevers, stomach issues, and mental illnesses. The secretions were also used in soaps and creams, and at one point was added to cigarettes to enhance the scent. Hippocrates even wrote about castoreum's healing properties in 500 B.C. 'By the Roman period, it was a stock part of people's pharmacopeia,' says Francl. Castoreum's popularity as medicine likely has something to do with its chemical makeup. According to the 2022 book, castoreum can contain more than 75 different chemical compounds—an unusually high diversity. The molasses-like material also contains salicylic acid, or aspirin, which can alleviate pain. Castoreum also has fatty acids like those in expensive skin creams. And some of its molecules are structurally similar to vanillin, the compound in vanilla orchids that's responsible for the trademark vanilla taste. Learn more about how vanilla is produced in São Tomé and Príncipe. Unfortunately, the demand for castoreum came at a cost. It was a byproduct of the centuries-long fur trade, which decimated North American and Eurasian beaver populations, nearly rendering both species extinct by the 16th century in Europe and the 19th century in North America. Castoreum plays a vital role in beavers' everyday lives. To mark their territory, both beaver species deposit mud piles on the ground and excrete castoreum on top. This serves the threefold purpose of elevating the odor, adding moisture to the scent to make it more potent, and protecting the smell from rising water levels, according to Dietland Müller-Schwarze in his 2011 book The Beaver: Natural History of a Wetlands Engineer. While both males and females have castor sacs, adult males in a family are most likely to leave scent markings in strategic locations—like the pathways of other beavers—to send the message that this land is taken. Indeed, when Campbell Palmer smells castoreum in her research in Great Britain, she knows right away 'there's probably two families here, and they're telling each other, 'This is the line. This is my boundary,'' says Campbell-Palmer, head of restoration at Beaver Trust, a U.K.-based organization dedicated to increasing Eurasian beaver populations. Read how beavers are bouncing back in Sweden. 'It's a very distinctive smell, castoreum…it's kind of musky, but sweet,' says Campbell-Palmer. 'Even if you don't see beavers about, you know they're there.' Related beavers can also recognize their family members' individual castoreum scents, which is also a useful tool for Campbell-Palmer. When she wants to trap and relocate a family of beavers, she can extract one animal's castoreum and put it in a humane trap to attract its relatives. 'They're doing very well in Britain,' Campbell-Palmer adds. 'They're adapting readily.' The North American species is also rebounding, thanks to habitat preservation and hunting controls. If castoreum were ever to appear in something you ate, Francl says not to worry. 'When we're thinking about food, what really matters is the structures of the molecules,' says Francl. 'It doesn't matter whether it comes from bear or it comes from beaver, it's the same molecule—it does the same thing.' The U.S. Food and Drug Administration classifies castoreum as 'generally regarded as safe,' and a 2007 safety assessment published in the International Journal of Toxicology concluded that 'a long historical use of castoreum extract as a flavoring and fragrance ingredient has resulted in no reports of human adverse reactions.' 'I would try it,' Francl says. But 'probably not in ice cream.' This story was originally published on October 1, 2013. It has since been updated.
