The Art of Preparing Tea for Use

“Tea being an infusion and not a decoction like coffee, it should be brewed not stewed, the chief object being to extract as much of the theine or refreshing principle as possible and as little of the tannin or astringent property as can be at the same time without either boiling or overdrawing it.”

Written by Joseph M. Walsh in 1896, Tea Blending as a Fine Art, provides a number interesting gems which stand out and make us appreciate the history, culture, and even the science behind the beverage. In this case, Walsh is making note that it’s important to revisit the basics now and then to ensure that consumers of tea are preparing it correctly in order to get the most enjoyment. Specifically, brewing or steeping tea is done relatively quickly, with the intention of extracting the various plant compounds which directly impart taste.

Theine (the Refreshing Principle) and Tannin

The theine or refreshing principle referred to by Walsh in 1896 was none other than caffeine and while it was eventually recognized as the same substance as any other caffeine, the extraction of caffeine remains a major objective for many of us who can’t pass a morning without at least one cup. However, tea, like grapes, contain tannin which in significant concentrations will yield a bitter taste. All true tea from the camellia sinensis plant contain both caffeine and tannin though the variety of plant, its growing conditions, and the contents of the soil (or terrior) have an impact on the amount. Additionally, the processing of the tea from a white through to an oolong and black significantly impacts the amount of tannin found in the leaves.

Extracting The Goodness from Tea Leaves

Steeping Tea Leaves Over Time

The Longer You Steep the More Flavor Compounds and Bitter Tannin Emerge – We Seek Balance

Apparently, back in the late 1800’s there were enough people steeping tea incorrectly that Walsh felt it was critical to teach consumers how it was done. First, he notes that “the consumer should purchase only the best tea, it requiring much less of the finer grades to make good tea than of the common kinds, and will prove the most economical in the end.” Walsh goes on to describe misconceptions that the strength of a cup of tea was measured by dark color, leading to practices like adding tea to cold water and bringing to a boil, or stewing tea in boiling water for a prolonged period of time. Both of these provide a dark liquor but also an extremely bitter infusion.

When steeping tea the goal is to use good quality water, at the right temperature, for just the right amount of time to get the best tasting cup of tea possible while minimizing the bitter qualities of tannin. For loose leaf tea this means three important things; using good quality water, keeping the tea in contact with the water for the right amount of time, and using the right temperature water for steeping. Good quality water ideally means soft water, freshly boiled. The water should certainly not be distilled nor should it have been previously boiled water that has been re-boiled.

Forlife Folding Handle Tea Infuser

Folding Handle Infuser

Separating the leaves from the water is also critically important. There are any number of ways to do this of course, using a reusable infuser or strainer or single use paper tea bag. For those more adventurous, a gaiwan, yixing teapot, or kyusu are great ways to steep tea in a more traditional way.

Finally, the right temperature is also very important. While boiling water works well for black tea and many oolongs, its isn’t the best for all types of tea. Using boiling water on green or white teas in particular will extract far too much tannin making your tea very bitter. With many teas, green, white,  and yellow in particular, steeping with cooler water often brings out far more favor.

Steeping Time and Temperature

Below you will find very general steeping times and temperatures when using a single serve tea bag or infuser. These are general guidelines however since, as we noted earlier, the amount of various flavor compounds and tannin can vary significantly from tea to tea based on plant variety, growing conditions, and processing.

  • White Tea – 170° – 185° for 1-3 minutes
  • Green Tea – 170° – 185° for 3-5 minutes
  • Yellow Tea – 160° – 170° for 4-5 minutes
  • Oolong Tea – 185° – 212° for 3-5 minutes
  • Black Tea – 190° – 212° for 3-5 minutes

If you don’t happen to have a thermometer readily available, fear not. Poured into a room temperature mug, boiling water will almost immediately drop the the high 190°’s. If you want to get water for green and white teas just wait 2-5 minutes before adding the infuser. For yellow tea, wait a bit longer, about 5-7 minutes before adding tea. Conversely, since boiling water will almost immediately cool, its best to pre-heat your mug for black and many oolongs by adding boiling water, discarding, and adding fresh water with the infuser already in the cup.

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Your Caffeine Assumptions About Tea Are Wrong! (Sorry)

Two leaves and a bud of camellia sinensis (tea) plant contain the most caffeine of any part of the plant.

Bud and Two Leaf – Desired Pluck and Highest in Caffeine – By Mandeep Singh, CC-BY-SA-3.0

We recently wrote about the caffeine in tea, specifically looking into claims that caffeine in tea was somehow different than caffeine found in coffee, soda, or other products. We found that the jury was still out on the topic, with some studies showing that the combination of L-theanine and caffeine was less jolting. However, these studies used much greater quantities of L-theanine than is normally found in tea. This brings us to the next topic around how much caffeine is in tea. A search of web pages reveals a wide variety of information with many charts showing black tea as having the most caffeine followed by oolong, green, and white in descending order. We went searching to learn more about what things impact the amount of caffeine in tea and what ends up in your cup.

The Role of Caffeine in Tea

First lets set the stage a bit. Caffeine is found in true tea from the camellia sinensis plant. It is not found in herbals and tisanes like products featuring rooibos, honeybush, or other herbs. Many plants including both coffee and tea naturally produce caffeine as a way to protect themselves. Caffeine, like other compounds including nicotine and morphine, is a bitter tasting alkeloid, a feature which helps ward off many insects that would otherwise feast on plant leaves. It also tends to inhibit the growth of fungus thereby further protecting the plant. (Freeman and Beattie)

Recent research also suggests that there may also be another reason for caffeine in plants; to attract honeybees. Specifically, researchers have suggested that in low doses, having caffeine in pollen helps honeybees better identify the scent of a given flower providing a bit of reproductive advantage. (Wright, Baker, et all).

Caffeine and Types of Tea

Understanding that the presence of caffeine in tea is a self defense mechanism and that new growth is most vulnerable to insect attack, it should come as no surprise that the most desired part of the tea plant also has the highest caffeine. Specifically the bud and newest leaves, which are highly regarded for many types of tea, provide more caffeine than older growth. However, this isn’t the end of the story. The tea plant, c. Sinensis has evolved naturally over time into many varieties to suit the area in which they are grown. The sinensis and assamica varieties are the most notable but not the only varieties. Additionally, many countries including Japan, China, India, and Kenya actively work on producing specialized clones more suited to specific growing conditions, desired tastes, and leaf appearance. Each variety of plant differs in the amount of caffeine it produces and even the specific season of growth and available nutrients all impact caffeine production.

All types of tea, including green, black, white, and oolong, come from the same plant. The drying, rolling, and oxidization to achieve finished product does vary from type to type but the varieties still come from the same basic plant. Nothing in the standard production process extracts or otherwise removes caffeine from the leaves.

So what does this mean? Unless producers and retailers are sampling large volumes of leaf, for each and every product they offer, its really impossible to make specific claims about the amount of caffeine in any type of tea. It will fluctuate wildly within a very wide range; white, black, green, or otherwise. One might be able to avoid high amounts of caffeine by avoiding teas that are all tips but even this is no guarantee.

Decaffeinated Tea

An alternative for many is to look for decaffeinated tea which theoretically allows enjoyment of tea without the caffeine. There are two general methods used in the decaffeination process of tea today; ethyl acetate (also known as “naturally decaffeinated”) and CO2. In the first case, ethyl acetate, which occurs naturally in the tea plant, is used to wash the tea leaves removing caffeine (as well as many other beneficial substances and flavor compounds) from the product. The washed tea leaves are then dried and repackaged. In the case of CO2, the leaves are also washed. This is done under more than 60 lbs of pressure per square inch (psi) at which point CO2 becomes a liquid. After washing the tea in liquid CO2 the leaves return to normal pressure at which point the remaining liquid CO2 simply evaporates. Both decaffeination processes are expensive, time consuming, and remove more than just the caffeine resulting in some compromise in taste and other compunds found in tea.

Aside from the impact on taste and other compounds, the process of decaffeination does remove most of the caffeine found in tea. If you live in the European Union and you buy decaf tea then you are in great shape. To meet EU standards a decaf product must have 99.9% of the caffeine removed. In the United States we aren’t quite as exacting, requiring only 97% removal. So if we assume that the amount of caffeine in any given tea sample may vary widely then so too might the amount of caffeine in your decaf tea.

Rooibos, Honeybush, and Tisanes naturally are caffeine free.

Adirondack Berries – A Rooibos Based Tisane

Its worth noting that there is a myth floating about that you can eliminate most of the caffeine in tea by doing a quick initial steep, tossing the liquor, and re-steeping. Unfortunately the data under controlled conditions doesn’t support this myth at all. To eliminate the caffeine you would need to steep for 10-15 minutes, toss the liquor, and then steep again but who would want to drink that? For a much more in-depth look at caffeine and tea have a look at Caffeine and Tea:  Myth and Reality by Nigel Melican which is one of the best reviews we have seen to date on the subject.

In summary, while the amount of caffeine in any given sample can be measured by a lab, as far as we can tell its really impossible to make sweeping claims about the amount of caffeine in any specific type of tea, much less one specific tea product. When we want to skip the caffeine we’ll have a a tisane or herbal tea.

Sources Cited

Freeman, B.C. and G.A. Beattie. 2008. An Overview of Plant Defenses against Pathogens and Herbivores. The Plant Health Instructor. DOI: 10.1094/PHI-I-2008-0226-01, http://www.apsnet.org/edcenter/intropp/topics/Pages/OverviewOfPlantDiseases.aspx

G.A. Wright, D.D. Baker, M.J.Palmer, J.A. Mustard, E. F. Power, A. M Borland, P.C. Stevenson. Caffeine in floral nectar enhances a pollinator’s memory of reward. Science. Doi 10.1126. Science., http://www.ncl.ac.uk/press.office/press.release/item/bees-get-a-buzz-from-caffeine

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Is caffeine from tea less jolting?

Caffeine Chemical Makeup

Chemical Makeup of Caffeine

We love tea as much as the next person (okay perhaps a bit more). We are also a bit geeky by nature so we are fascinated to learn more about tannins, polyphenols, terrior, and other science related topics in the world of tea. We have also learned to be a bit skeptical as well. There are loads of claims attributed to tea being able to cure all kinds of health problems. There seems to be no end to the claims made around tea and tisanes. Most of these claims, however, utterly lack quality sources and rigorous scientific inquiry.

So it is with one of the more fascinating claims we have come across; that the caffeine in tea is somehow different or better than that found in coffee. Specifically, there are quite a number of websites claiming that the caffeine in tea is either “slow release” or is absorbed into the bloodstream more slowly. As the theory goes, this property makes tea a better choice because it doesn’t have the significant quick jolt found in coffee. What’s more the theory suggests that the caffeine stays with you longer, providing an enhanced sense of alertness and clarity.

How Caffeine is Generally Accepted to Impact the Body

It turns out that caffeine causes quite a number of reactions inside the body stemming largely from the brain. Specifically, as the body gets tired it is believed that adenosine molecules builds up in the brain where they attache to aptly named adenosine receptors. This in-turn causes you to feel drowsy and triggers sleep. It turns out that caffeine fits nicely into those adenosine receptors where the brain happily doesn’t get the message that it should be tired. In a cascading effect, it is believed that neurons in the brain begin firing because of the blocked adenosine receptors, the body begins to think its under attack, and the pituitary gland starts releasing adrenaline and the body goes into fight or flight mode, ready for anything.

Caffeine in Tea is Somehow Different

Tea Leaves in Gaiwan

Steeping Tea Leaves by Wikimol, CC BY-SA-3.0

All this leads us back to the earlier theory about how the caffeine in tea is somehow different from caffeine found in coffee, soda, or myriad other products. Realistically, caffeine is caffeine is caffeine.  It’s all the same molecule, whether it’s coming from tea, coffee, chocolate, medicine, or so-called energy drinks. What is fascinating, however, is how the body behaves when caffeine is ingested with other substances. While tea has long been believed to deliver a less jolting caffeine effect science hadn’t been able to explain it (and really still hasn’t).

There have recently been a few studies which look at caffeine in combination with compounds present in tea that appear to shed light on the subject. In particular, research has been looking at L-theanine, an amino acid found primarily in plants and fungus materials in combination with caffeine. Tea, as should be obvious at this point, contains L-theanine. Researchers in two different studies (referenced below) have found some linkages in the combination of the two compounds to favorable alertness, cognitive performance, blood pressure, and heart rate. The kicker, however, is that the study participants were given 40-50 mg of caffeine and 90-100 mg of L-theanine.

According to research by Dr. Emma Keenan at the University of Bristol (UK), a standard cup of black tea, quoted as 200 ml or a bit over 6 oz, has 24.2 +/- 5.7 mg of L-theanine. This is one quarter the amount given to study participants when looking at the combination of both caffeine and L-theanine.  For green tea this was even lower at 7.9 +/- 3.8 mg of L-theanine. Even if you double the amount of tea consumed to a (perhaps) more reasonable 400 ml or 12-13 oz, the amount of L-theanine is still about half the amount used in study.

For its part caffeine varies wildly in a cup of tea ranging loosely between 30 and 120 mg of caffeine (we will be doing another blog soon which may further challenge assumptions about caffeine in tea).

So is Caffeine in Tea Different?

From our vantage the caffeine in tea isn’t different at all.  Its still caffeine.  What may be different is how the body responds to the combination of tea, L-theanine, and other compounds present in tea. There is promising research to suggest that L-theanine in combination with caffeine may boost alertness and cognitive response but we wouldn’t feel comfortable making that claim without more research and realistic dosages that mimic real-world consumption of tea.

Sources Cited

The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness, by Giesbrecht T, Rycroft JA, Rowson MJ, De Bruin EA, http://www.ncbi.nlm.nih.gov/pubmed/21040626

The combined effects of L-theanine and caffeine on cognitive performance and mood, by Owen GN, Parnell H, De Bruin EA, Rycroft JA, http://www.ncbi.nlm.nih.gov/pubmed/18681988

How much theanine in a cup of tea? Effects of tea type and method of preparation’, by Keenan, E, Finnie, M, Jones, P, Rogers, P & Priestley, C 2011, Food Chemistry, vol 125., pp. 588 – 594, http://www.bristol.ac.uk/expsych/people/emma-k-keenan/pub/2957550

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