by Lori Way, MS, RD
Have you ever tasted a tea that a friend recommended and absolutely hated it? Or you’re reading tea reviews online and see your favorite tea bashed. You can’t understand how someone could not enjoy your favorite, nor how anyone on earth could like the one you just threw down the sink in disgust. Sure, sometimes you can chalk it up to the brewing method, which can indeed lead some teas to taste more bitter, for example. But YOU didn’t brew it wrong — it was just bad tea, right? Well, as usual, it’s more complicated than that.
While at the World Tea Expo 2011 last weekend, I attended a very interesting workshop about the science of taste, specifically as it relates to tea tasting. It was a combination of lecture and hands-on tasting and smelling of various flavor components and, of course, tea. Although I had been exposed to the science of taste while in college as part of my dietetics training, I am by no means an expert. I found this introductory course to be something I could really, um, sink my teeth into, and am planning on delving deeper into this topic to improve both my understanding of the science and my palate. So I’m presenting this information not as an expert, but more as an exploration. I welcome your comments, corrections, and insights.
The point of the workshop was to find out our baseline tasting abilities and to learn how to improve it. In writing about this, I’m hoping some of you will be able to improve your own skill. My tasting ability wasn’t quite as acute as I thought it might be, so I have some work to do. Luckily, tasting things is not really what I consider an unpleasant job!
Among the first things we discussed was that taste and flavor aren’t exactly the same thing. Taste refers to the sensation from your taste buds, and is commonly broken down to bitter, salty, sweet, sour, and umami (the savory taste of high protein foods). Flavor on the other hand involves taste, smell, and also the trigeminal system. This refers to the trigeminal nerve, which innervates the jaw, tongue, nose, throat, palate, and eye, and helps us determine the mouth-feel of a food. The astringency (or drying nature) of tea would be an example of mouth feel, or the hot feeling of certain peppers. Smell is also a critical component of flavor, as you have probably already noticed when you’ve had a cold and can’t taste anything.
I’d like to spend a bit of time on each of these three components of flavor: taste, smell, and the trigeminal system, so I’ll focus on taste for this post and devote another two to the others.
A few quick facts about taste:
- The map of the tongue you may have learned about in the past has been disproved. All taste buds can taste everything.
- We each have about 10,000 taste buds, and damaged ones take 7-10 days to heal.
- Caffeine contributes to the bitter taste of tea.
- L-theanine contributes to the umami taste of green tea.
- I just read an article about fat as another possible taste. Here it is, if you are interested: Poor ‘Fat Tasters’ May Tend to Be Heavier.
Taste serves us well by alerting us to potential poisons, which are often very bitter. It can also help us distinguish some of the nutritional value of foods. High protein foods, for example, have the umami taste due to the presence of the amino acid glutamate; sweet can indicate ripe fruit; sour, unripe fruit and/or vitamin C.
In our workshop, each table was given five large cups of liquid, labeled A-E. We each took a small sample and tasted it. Then we had to decide which of the five tastes the sample represented. Each sample had dissolved in it a precise amount of either sugar, salt, a bitter compound (primarily caffeine), citric acid (for sour taste), and MSG (monosodium glutamate) for the umami taste. The samples were created such that the percentages of each flavor component were equal among all the samples (0.25% by weight). Nevertheless, for me, the samples seems to vary in strength. I found the sweet sample to taste just like plain water (although we didn’t have plain water to compare with). The umami seemed relatively mild also. I found the salty and bitter tastes to be somewhat moderate in strength. But the sour one almost took my head off. I hated it. At first it didn’t even register as sour, it was so strong to me. I found that odd, because I like lemons, for example, and hot and sour soup, and things of that nature. We were also asked to think about a tea that each sample reminded us of. This was harder than I expected it to be. I came up with Sencha for bitter, hibiscus for sour, white or oolong for sweet. The salty sample didn’t remind me of any tea, and I fear I just didn’t spend enough time with the umami to get an association going. It was fairly subtle to me. Maybe I’ll buy some MSG and make my own sample.
Getting back to our scenario above where you hate your friend’s favorite tea, people’s sensitivity to tastes can vary quite a bit. In our workshop, not everyone reacted the way I did to the various tastes. You also may have heard of “super tasters” who are the most sensitive and tend to not care for overly spicy foods, for example. They are also good at discerning individual tastes and smells in a mixture. But other people are much less sensitive and need more of any given substance to be able to taste it. Likewise, they are less adept at identifying tastes and smells in a mixture. This sensitivity can depend on how many taste buds a person has, the number of receptors on those taste buds, and genetics. Research shows that not everyone can taste certain bitter chemicals, and in fact, almost 50% of the population does not have a functional taste receptor for bitter. This alone can go a long way to explaining tea preferences, since tea can definitely contain bitter tasting components. Also note that adding sugar or lemon to a bitter substance decreases the bitter perception, also helping to explain common tea serving practices.
Next time we’ll talk about aroma, an essential part of flavor. In the meantime, next time you’re browsing tea reviews, keep in mind that the reviewers’ taste mechanism may not resemble yours very much. The best way to tell if you like a tea is to taste it yourself, and preferably under the same conditions that you are most likely to drink the tea. In other words, if you have a breakfast tea sample, taste it with breakfast rather than in the middle of the afternoon. Time of day and food can greatly influence the taste!