Warm tea, warm heart

Researchers from the world-renowned, world-class institution, University of Colorado at Boulder (my alma mater. Go Buffs) conducted an experiment which found that participants judged others differently depending on the temperature of the beverage in their hands [15].

CU Professor Lawrence E. Williams asked a group of undergraduates to answer hypothetical questions about the personality traits of a fictitious person. First, however, on an elevator ride up to the lab, a busy lab worker overloaded with books, clipboards, papers, and either a steaming hot or icy cold cup of coffee would ask the participant to briefly help them hold the cup while they organized their things. Of course, the participants were unaware that this was an important part of the experiment. In the end, the study found that participants who held the hot coffee cup were more likely than those who held the cold cup to judge the fictitious person in the experiment as more generous or caring, (i.e. “warm” personality traits).

In a follow-up study, participants held either heated or frozen therapeutic packs as part of a “product evaluation study,” after which they were told they could receive a gift certificate for either a friend or themselves. Those who held the hot pack were more likely to ask for the gift certificate for a friend, while those who held the frozen pack tended to keep the gift for themselves.

Yale University psychologist and co-author of the study, John A. Bargh, explained, “It appears that the effect of physical temperature is not just on how we see others, it affects our own behavior as well. Physical warmth can make us see others as warmer people, but also cause us to be warmer – more generous and trusting – as well.”

The explanation for this ‘warm-breeds-warmth’ hypothesis may reside in an area of the cerebral cortex called the insula, or insular cortex. The insula is believed to be involved in consciousness, and play a diverse role in a few important human functions, including regulation of emotion (particularly empathy) and bodily homeostasis, including body temperature.

So, it could be the insular cortex where warm emotions and physical warmth overlap. Regardless, the next time someone cuts you off in traffic, clutch tight to a warm mug of tea with both hands… but also keep two hands on the wheel. Perhaps pour the hot tea over the steering wheel first and grab onto that… Idk, I’m just thinking out loud.

High heat, bold flavor

As I recently described in a blog about White Tea, I believe a false narrative exists that mistakenly profiles white tea as fragile and delicate, requiring low water temperatures so it doesn’t over-steep. What I have observed anecdotally and in the scientific literature suggests that white tea may be best at higher temperatures than what people are often told to use. I found an interesting study where 12 trained panelists tasted white tea infused at various temperatures [14].

Results showed that brewing at 70 °C/158 F (the commonly, and I believe mistakenly, recommended temperature for white tea) only reached 13% of likes, similar to that obtained for 80 °C/176 F (14%). An increase in preference (27%) was obtained with water at 90 °C/194 F, and infusion in boiling water (98 °C/ 204.8 F) was preferred by the largest number of panelists (43%) [14].

Last year in West Lake, Hangzhou, my friend Maria and I recorded this video. A local shopkeeper was preparing white tea by boiling it (decocting it) for 10-15 minutes. Far from bitter, the vibrant amber liquor was smooth, rich, and savory, with an unusually long and sweet finish. We loved it.

The likeability correlated to the perception of the taste as “strong.” Put simply, hot water extracts more total compounds, creating a “stronger,” more robust flavor profile. Since white tea contains much fewer catechins than green tea, a long hot infusion is not overly bitter like a green tea would be. Moreover, the rich amino acid profile of white tea helps to balance what catechins do remain in the leaves, creating a strong, rich and well-balanced flavor (assuming the leaf itself is of good quality).

I am not saying that high heat is always best for flavor, particularly when it comes to green and some oolong teas. High heat merely turns up the volume dial and some tea types are best played loud. Depending on the tea and your personal preferences, you can adjust the dial however you see fit. I’m just saying that you might be surprised to find white teas taste best banging through your speakers at 205 degrees.

A figure from a study by Pérez-Burillo et al. [14], showing instances of preference for white tea a 5 different infusion temperatures

Can cool you down?

Counterintuitively, hot drinks can cool you down on a hot day. The heat from a warm cup of tea goes straight to your core, causing your body to think it’s hotter than it really is, eliciting a sort of over-heating reaction. This causes the body to sweat (sweating is key) and diverts hot blood to your skin, which can cause you to lose more heat than you initially gained from the hot tea.

This concept was put to the test in a 2012 experiment, in which 9 male participants cycled for 75 minutes with body heat sensors monitoring their core temperature. Total body heat retention was lowest when they consumed 50-degree Celsius (122 F) water (the warmest temperature measured in the study) compared to 1.5, 10, and 37 degrees (34.7, 50, 98.6 Fahrenheit, respectively) [16]. In other words, hotter water led to lower body temperature.

The explanation here boils down to good ol’ sweat. When sweat evaporates, the energy stored as heat is removed from the body. BUT, you need to let the sweat evaporate. If you wipe the sweat away, or it’s too humid out, the sweat won’t evaporate, and you won’t lose the heat.

In the study mentioned above, participants were cycling on stationary bikes positioned in front of large fans, allowing sweat to evaporate easily. Considering the importance of sweat evaporation, it may be that this particular benefit of hot tea consumption is mainly relevant to outdoor athletes, or people with access to a breeze and dry air.

On the other hand, If you’re at a cocktail party and you start to feel toasty in your cotton button-down, don’t reach for the boiling hot tea in hopes that it will cool you down (speaking from experience). The cotton fabric turns right into a sweat sponge, giving you the ‘sweaty guy’ look that foiled my efforts to impress Karen from HR. (second chance, Karen? I won’t drip into your cocktail this time)

Welp, this wraps up Part 2 of the blog series on high-heat infusions. We’ve covered quite a bit of material on hot water extraction, and how warm infusions can provide:

  • more antioxidants
  • more caffeine
  • more empathy
  • more flavor
  • more body-heat dissipation

Please feel free to comment here or reach out on IG @WuMountainTea with questions, comments, thoughts, etc. Cheers and thanks for reading!

P.S. Heat-retaining tea tumblers are an awesome way to preserve the temperature of your infusion (hot or cold) over long periods of time. If you actually want to steep your tea at, say 190 degrees for 30 minutes, it is difficult to do that in a conventional teapot, since the pot will lose a lot of heat over a 30-minute timeframe. A heat-retaining tea tumbler, however, allows the luxury of a long-hot, or a long-cold infusion, and the convenience to take that with you on the road. I have been using one, and only one, every day for the last 3 years. It is the Everest tea tumbler from The Tea Spot. It’s a great product and I highly recommend it.

Works Cited

[1]: Uttara, B., Singh, A., Zamboni, P., & Mahajan, R. (2009). Oxidative Stress and Neurodegenerative Diseases: A Review of Upstream and Downstream Antioxidant Therapeutic Options. Current Neuropharmacology,7(1), 65-74. doi:10.2174/157015909787602823

[2]: Aristizabal, L. S., Ortíz, A., Aristizabal, M. F., & Villada, J. F. (2017). Comparative Study Of The Antioxidant Capacity In Green Tea By Extraction At Different Temperatures Of Four Brands Sold In Colombia. Revista Vitae,24(2), 133-145. doi:10.17533/udea.vitae.v24n2a06

[3]: Komes, D., Horžić, D., Belščak, A., Ganić, K. K., & Vulić, I. (2010). Green tea preparation and its influence on the content of bioactive compounds. Food Research International,43(1), 167-176. doi:10.1016/j.foodres.2009.09.022

[4]: Guo, L., Guo, J., Zhu, W., & Jiang, X. (2016). Optimized synchronous extraction process of tea polyphenols and polysaccharides from Huaguoshan Yunwu tea and their antioxidant activities. Food and Bioproducts Processing,100, 303-310. doi:10.1016/j.fbp.2016.08.001

[5]: Vuong, Q. V., Golding, J. B., Stathopoulos, C. E., Nguyen, M. H., & Roach, P. D. (2011). Optimizing conditions for the extraction of catechins from green tea using hot water. Journal of Separation Science,34(21), 3099-3106. doi:10.1002/jssc.201000863

[6]: Lin, S., Yang, J., Hsieh, Y., Liu, E., & Mau, J. (2013). Effect of Different Brewing Methods on Quality of Green Tea. Journal of Food Processing and Preservation,38(3), 1234-1243. doi:10.1111/jfpp.12084

[7]: Perva-Uzunalić, A., Škerget, M., Knez, Ž, Weinreich, B., Otto, F., & Grüner, S. (2006). Extraction of active ingredients from green tea (Camellia sinensis): Extraction efficiency of major catechins and caffeine. Food Chemistry,96(4), 597-605. doi:10.1016/j.foodchem.2005.03.015

[8] Liang, H., Liang, Y., Dong, J., & Lu, J. (2007). Tea extraction methods in relation to control of epimerization of tea catechins. Journal of the Science of Food and Agriculture,87(9), 1748-1752. doi:10.1002/jsfa.2913[9] DOI 10.1007/s13197-014-1487-3

[10] Limin Xiang, Shunshun Pan, Xingfei Lai, Lingli Sun, Zhigang Li, Qiuhua Li, Yahui Huang, Shili Sun (2018). Optimization of brewing conditions in epigallocatechin-3-gallate (EGCG) extraction from Jinxuan summer green tea by response surface methodology. Journal of Applied Botany and Food Quality, 91, 163 – 170 (2018), DOI:10.5073/JABFQ.2018.091.022

[11]: Castiglioni, S., Damiani, E., Astolfi, P., & Carloni, P. (2015). Influence of steeping conditions (time, temperature, and particle size) on antioxidant properties and sensory attributes of some white and green teas. International Journal of Food Sciences and Nutrition,66(5), 491-497. doi:10.3109/09637486.2015.1042842

[12]: Braud, L., Peyre, L., Sousa, G. D., Armand, M., Rahmani, R., & Maixent, J. (2015). Effect of Brewing Duration on the Antioxidant and Hepatoprotective Abilities of Tea Phenolic and Alkaloid Compounds in a t-BHP Oxidative Stress-Induced Rat Hepatocyte Model. Molecules,20(8), 14985-15002. doi:10.3390/molecules200814985

[13]: Langley-Evans, S. C. (2000). Antioxidant potential of green and black tea determined using the ferric reducing power (FRAP) assay. International Journal of Food Sciences and Nutrition,51(3), 181-188. doi:10.1080/09637480050029683

[14]: Pérez-Burillo, S., Giménez, R., Rufián-Henares, J., & Pastoriza, S. (2018). Effect of brewing time and temperature on antioxidant capacity and phenols of white tea: Relationship with sensory properties. Food Chemistry,248, 111-118. doi:10.1016/j.foodchem.2017.12.056

[15]: Williams, L. E., & Bargh, J. A. (2008). Experiencing Physical Warmth Promotes Interpersonal Warmth. Science,322(5901), 606-607. doi:10.1126/science.1162548

[16]: Bain, A. R., Lesperance, N. C., & Jay, O. (2012). Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation. Acta Physiologica,206(2), 98-108. doi:10.1111/j.1748-1716.2012.02452.x

[17]: Lantano, C., Rinaldi, M., Cavazza, A., Barbanti, D., & Corradini, C. (2015). Effects of alternative steeping methods on composition, antioxidant property and colour of green, black and oolong tea infusions. Journal of Food Science and Technology,52(12), 8276-8283. doi:10.1007/s13197-015-1971-4[18]: doi: 10.1111/1750-3841.13149

[19]: Fulgoni, V. L., Keast, D. R., & Lieberman, H. R. (2015). Trends in intake and sources of caffeine in the diets of US adults: 2001–2010. The American Journal of Clinical Nutrition,101(5), 1081-1087. doi:10.3945/ajcn.113.080077 [20]: Mahoney, C. R., Giles, G. E., Marriott, B. P., Judelson, D. A., Glickman, E. L., Geiselman, P. J., & Lieberman, H. R. (2018). Intake of caffeine from all sources and reasons for use by college students. Clinical Nutrition. doi:10.1016/j.clnu.2018.04.004