Oolongs and fall fruits

Sara Shacket and her friends have been doing a series on tea pairings that is absolutely fascinating! The latest is about pairing oolongs with fruit, which you can find here:

http://www.tea-happiness.com/2017/10/tea-pairing-101-oolong-and-fruit.html

That page has links to the tasting notes by Georgia (http://www.notesontea.com/2017/10/tea-pairing-101-oolong-tea.html) and Jee (https://www.ohhowcivilized.com), who shared in the experience, and had similar takes on the results. Be sure to read all three blogs about the pairings, because each reveals a different aspect of the experience.

The teas were a Taiwanese Bao Zhong, which is lightly oxidized (typically around 10%), a classic Chinese Tie Guan Yin, and an equally classic Xiao Hong Pao (Little Red Robe), which was the most oxidized of the three.

What oxidation does is to shift the tea's flavor profile from vegetal and "cool" to more chocolatey, sweet, and "warm."

The three fruits were pear, plum, and persimmon, chosen because they are all fall fruits. It so happens that these three fruits also fall on a spectrum from "cool" to "warm." 

Teas from left to right, Bao Zhong, Tie Guan Yin, and Xiao Hong Pao.
Image from  http://www.tea-happiness.com/2017/10/tea-pairing-101-oolong-and-fruit.html

Here are the overall results, compiled from the three bloggers: 

The pear went reasonably well with the Bao Zhong, as you would expect because both tend to activate the "cool" receptors, though the Bao Zhong, described as only somewhat vegetal, would be less effective with pear than, say, a green tea. 

The Tie Guan Yin was happiest with the persimmon. The persimmon was described as very sweet—it was one of the persimmon cultivars, Fuyu, that is not naturally astringent.* Sara  described the sweetness as "cloying." A major volatile flavor compound in persimmon is benzaldehyde, which has a characteristic sweet almond/cherry quality with nutty/woody nuances, and to my nose can indeed be very cloying. Bennzaldehyde activates the warm to hot receptors. Turns out that the more roasted an oolong is the less benzaldehyde it contains—so it is not surprising that Tie Guan Yin would go better with the persimmon than the more highly roasted Xiao Hong Pao.**

Plums went best with Xiao Hong Pao. Plum cultivars vary tremendously in their composition, but one constant is the presence of lactones such as gamma-decalactone and gamma-dodecalactone.*** These lactones have a waxy fruity quality and tend to activate the warm/hot receptors.**** Interestingly, plums also have several compounds such as linalool and hexanol that activate the cool receptors. Sara, though not the others, noted that the plums went well with the lightly oxidized Bao Zhong: in contrast with the pear, "The plum turned out to be a better choice. Its sweetness worked well with the floral and savory notes, but didn't overpower the palate. The tart plum skin transformed the tea flavor, creating an interesting depth." My guess is that the depth came from the back and forth across the cool to warm receptors that each activated.

Which brings me to what I thought was the most fascinating observation with these pairings, about the pear and the Xiao Hong Pao, as described by Sara: 

"We had a strange experience with the pear- it seemed to erase the flavor of the tea, but then a moment later the tea lingered on the palate. Jee decided that the pear was similar to a palate cleanser, which was an interesting thought!"

It was indeed an interesting thought! What palate cleansers, such as the cool sorbet of classical French banquets, do is to reset the balance of the trigeminal system. Here's how this works:

The response of trigeminal receptors at the "hotter" end of the spectrum is slow-on slow-off, while the response of those at the "cooler" end is quick-on quick-off. Think about eating a chili-laced food. At first you may not think it's too spicy, but then the heat sneaks up on you—that's the slow-on. You reach for some ice water, which quickly cools down the burn—that's the quick-on. But wait a few seconds and the cool receptors turn off and the heat returns! Signals from the "hot" receptors were just suppressed, but because they are slow-off, they were still active when the "cool" receptors had stopped sending signals to your brain. Remember that the sequence here is important.

This is exactly what was happening with the pear and the Xiao Hong Pao. This highly oxidized tea is full of chemicals that activate receptors at the hotter end of the trigeminal spectrum, while the pear activates receptors at the cooler end. Sip the tea, and the hotter end is activated. Bite into the pear, and the tea disappears. Wait a little, the pear flavor vanishes and the tea effect (which has been there all along) returns.

I've not mentioned here that all three bloggers found that honeycomb went well with all the teas, and managed to cover up what I would call the disagreements among the tea and fruit flavors. That will be a discussion for another blogpost.

And to find out more about the trigeminal system and what it means for tea and tea pairing, find my book "Three Basic Teas & How to Enjoy Them" at Amazon!

* Lyon, B. G., Senter, S.D. and Payne, J.A. (1992), Quality Characteristics of Oriental Persimmons (Diospyros kaki L. cv. Fuyu) Grown in the Southeastern United States. Journal of Food Science, 57: 693–695. doi:10.1111/j.1365-2621.1992.tb08074.x

** For the chemical profiles of panned and unpanned oolongs, go to: Sheibani E, Duncan SE, Kuhn DD, Dietrich AM, Newkirk JJ, O’Keefe SF. Changes in flavor volatile composition of oolong tea after panning during tea processing. Food Science & Nutrition. 2016;4(3):456-468. doi:10.1002/fsn3.307. You can find the article online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4867765/.

*** Y. H. Hui, Feng Chen, Leo M. L. Nollet. Handbook of Fruit and Vegetable Flavors. John Wiley and Sons, 2010. Also, go to http://www.flavours.asia/uploads/7/9/8/9/7989988/flavor_of_plums.pdf

**** Incidentally osmanthus, which goes so well with Tie Guan Yin, also has these lactones.