Latest news with #Steeped:TheChemistryofTea
The Star
a day ago
- 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
a day ago
- 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
The Guardian
25-02-2025
- Health
- The Guardian
Brewing tea removes heavy metals from water, study finds
The medicinal effect of a cup of tea is no surprise to anybody who has headed straight to the kettle after a laborious work meeting. But researchers say they may have found a more scientific explanation for why it is associated with health benefits. Scientists at Northwestern University in the US have found the brew removes charged atoms, or ions, of heavy metals from water. Benjamin Shindel, the first author of the research, said that while scientists may consider whether the flavour chemicals in tea are driving associated health benefits, the new study suggests an alternative. 'I think the one possible better explanation might be that it's because it's removing metals from water,' he said, adding the team found a cup of black tea brewed for five minutes reduced the concentration of lead ions in water by about 15%. While the team did not test the possible ramifications for health, Shindel said that even in a country such as the UK, where lead levels in drinking water are unlikely to be high, there could be a small effect. 'It's possible that on the margins, tea consumption is reducing [people's] metal intake by a very small amount, and perhaps over the population of the UK, that's reducing diseases associated with metal consumption by another commensurately very small amount,' he said. Among other studies, previous research has suggested people who drink tea may have a lower risk of stroke, dementia and even death. Writing in the journal ACS Food Science & Technology, Shindel and colleagues reported how they brewed tea with different batches of water containing known concentrations of heavy metal ions. They then checked the concentration of these ions after different periods of steeping, using solutions without tea as controls. Working with black tea, they found the brew reduced the concentration of all the metal ions tested, including lead, chromium and cadmium. They then focused on lead, finding longer brewing times of black tea and higher temperatures of water were associated with a greater reduction in the concentration of lead ions. What is more, ground tea had a greater effect than whole leaves. The team also found that, at least for the batches they tested, black, green and white teas reduced the concentration of lead ions in the water to a greater degree than camomile, rooibos and oolong teas when left to steep for 24 hours to reach equilibrium. In the case of bagged tea, the materials also mattered, with empty cellulose bags found to reduce the concentration of lead ions, whereas empty cotton and nylon bags did not. Prof Michelle Francl of Bryn Mawr College in the US and the author of Steeped: The Chemistry of Tea, who was not involved in the work, said: 'If you are concerned about heavy metals in your water, don't think that drinking tea is the solution.' However, she added that the study 'suggests some interesting directions' for developing sustainable and accessible ways to 'removing contaminants from water, a critical need in many parts of the world'.
