Now that many of us are spending more time at home, we are also brewing tea at home more than before. Due to this, we have decided to take a closer look at the brewing process, and review the components that lead to a wonderful cup of tea. Things to keep in mind when brewing a perfect cup of tea include your water composition, temperature, steep time, water to leaf ratio, brew vessel, and the type of tea you are brewing. Together, these components perform a delicate dance that will bring you many great steeps.
Tea is made up of many different chemical components. Acknowledging these will help us understand later how they are affected by things like water composition and temperature.
These components include polyphenols, amino acids like L-theanine, enzymes, pigments, carbohydrates, alkaloids like caffeine, minerals and volatiles. Below is a closer look at some tea chemistry vocabulary.
Polyphenols: This is a category of compounds found in plants that are produced to defend the plant against things like ultraviolet radiation, parasites, and plant predators.
Flavonoids: These are the main type of polyphenols found in tea.
Tannins: A compound in the flavonoid group that contributes to the astringent taste of some teas, or the sensation of having a dry mouth when drinking some teas and wines.
Flavonols: A class of flavonoids that includes catechins.
Catechins: A group of flavonols found in tea, including (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC), and (-)-epigallocatechin-3-gallate (EGCG). These are the components of tea that are said to have health benefits.
Theaflavins: These form from catechins during the oxidation of tea leaves, and found more in oolong and black teas.
A variety of aspects determine how much of each of these chemical components are found in tea leaves. These include where the tea was grown, environmental factors, the season it was harvested, effects of pests and disease, and the process the leaves went through once picked. For example, black tea is more oxidized than green tea. Oxidization, or the browning of the tea leaves when cell walls are broken and polyphenols hit oxygen, is a process done to some tea leaves once they are picked in order to achieve a certain flavor profile. Oxidation will lead to more theaflavins in black tea because polyphenols are converted into new compounds. Japanese shade grown teas are another example of tea producers manipulating the plant in order to produce more of a certain chemical component that will help the tea achieve a desired flavor profile. Shade grown teas are covered because the sun turns amino acids into polyphenols. Amino acids such as L-theanine are responsible for some of the broth like, umami flavor profiles in tea. Therefore, tea producers and growers seeking a tea with umami characteristics such as a Japanese Sencha green tea will cover the tea plants to shade them from the sun, preserving the amino acids.
The combination of naturally occurring chemical components in tea plants, and the chemical changes that occur to tea when processed all contribute to all of the complex flavors we get out of a cup of tea. These chemical compounds are responsible for the aromas and tastes found in each unique tea and tea category. Generally speaking, teas within the same categories will have similar taste profiles due to being processed in similar ways. The Harney & Sons Guide to Tea describes these flavor profiles as follows. White and Chinese green teas are light in body, Japanese greens are thicker and brothy, oolongs coat your mouth with a milky or creamy sensation, and black teas are thicker and astringent.
These chemical components, found in different amounts in dry tea leaf categories based on place of origin, harvest season, and processing, will further react and change once introduced to water. The cup of tea that you drink is 98% water, and only 2% compounds diffused into water. Therefore, the quality of water you use when brewing tea will have an impact on the overall taste of your tea. Water that is too high in certain minerals, such as limestone, calcium oxide, magnesium, led, and chlorine should be avoided. Water too high in minerals can taste tinny and metallic. The amount of theaflavins, catechins, and caffeine extracted in tea can be impacted if your water is too high in certain minerals, such as calcium oxide. This can weaken positive flavor profiles produced by these chemical components of tea, such as sweetness or umami. High levels of magnesium and calcium oxide can also result in limescale buildup, surface film, or tea scum to form in your kettle or your cup of tea. Too little minerals in your water may also negatively impact the taste of your cup of tea, leaving it too dull. A water free from any harsh tastes or odors, a balanced mineral content, and a neutral PH level around 7 is ideal.
Lu Yu, a tea scholar who wrote The Classic of Tea during the Tang dynasty, suggested the best water to brew tea in is water from a mountain stream or spring in the same region the tea was produced. He said the leaves will reveal their true nature when in contact with the water they drank during their lifetime. Obviously, this is unachievable to the everyday tea drinker brewing from home. We are lucky, however, to have a variety of natural mineral springs right in our backyard. The State Seal Spring, located on the Avenue of the Pines in Saratoga Spa State Park, is often regarded as one of the springs with the best balance of minerals and PH levels. At Saratoga Tea & Honey, we use natural spring water gathered from the State Park for tea tasting occasions, such as the Aged Tea classes.
Water temperature is also an important component of tea brewing. Each tea category, due to levels of chemical components and processing, has a recommended brew temperature guideline. These are as follows, in Fahrenheit.
White, Spring Teas, Shade Grown Green: 160-170
Aged Tea: 212
The chemical composition of a cup of tea steeped at different temperatures will vary, sometimes greatly, and so will its taste. An increase in water temperature increases the kinetic energy of the water molecules, making them dissolve molecules in tea more easily. Different chemical components of tea leaves are more or less soluble at different temperatures. Water that is too hot for some delicate teas can dissolve chemical components like tannins and catechins too quickly, resulting in a negative bitter taste. Green tea tends to have more tannins than other types of tea, which is why it can turn more bitter than other teas when steeped in water too hot. Water that is too hot can also destroy or burn the desirable chemical compounds in tea that contribute to flavor. On the other hand, when tea is brewed in water that is too cold, with not enough kinetic energy, chemical compounds cannot dissolve properly, and tea will have less flavor complexity. Bringing water to a full boil and waiting for it to cool may not always be the best way to ensure your water is at the right temperature for your tea, since when water is boiled and cooled, oxygen is removed. This can have a negative effect on the flavor of your water. Keeping track of water temperature can be done with a variable temperature electric kettle, or a thermometer.
Time is also an important factor in brewing tea. Through osmotic diffusion, compounds on the surface and within the interior walls of tea leaves will diffuse into water, until the concentration of compounds in the leaves reach an equilibrium with the compounds in the water. Different chemical components of tea enter the water at different rates. Ones that are responsible for the aroma of tea tend to be the first, with caffeine, pigments, and tannins needing more time to diffuse. The trick to brewing a great cup of tea is to balance the right temperature of water with the right amount of brewing time to get all of the desired chemical compounds and components to diffuse into your water, without over-diffusing and creating negative flavors. If you increase the temperature of your water, try decreasing the time you steep your tea leaves. If you increase the time you steep your leaves, try decreasing the water temperature. Play around until you find the best combination to reach the desired flavors you want out of your tea leaves.
There are a few more factors that go into steeping your tea, including how much tea to use. Ideally, you would want to weigh the amount of tea in order to keep things consistent. We recommend about 2 grams of tea per 8 ounces of water, or one rounded teaspoon. How dense or airy your tea leaves are can change this ratio, so always experiment until you find the amount that fits your personal preference. The benefit of brewing whole leaf loose teas, in comparison to tea bags, is an increase in resteepability. The high ratio of leaf to water means there is a lot of flavor to be extracted from the leaves over multiple infusions. When given space to spread out in hot water, the tea leaf can rehydrate fully and chemical compounds can diffuse into your water over time. Broken, small pieces of tea leaves, often referred to as tea dust, diffuse their chemical compounds that make up flavor very quickly, and can’t be resteeped as many times. More nuanced, layered, and delicate flavors are also more prevalent in loose leaf teas. The brew vessel is also an important component of brewing the perfect cup of tea. Your vessel should allow your tea leaves enough space to spread out in the hot water. Preheating your brew vessel is another trick to ensuring you are steeping your tea leaves at an appropriate temperature. When water hits an unheated brew vessel, the temperature can drop significantly. There are many different vessels to choose from, ranging from traditional to more modern. Choose what works for you!
The final chemical composition of the cup of tea you consume is a result of these many factors. The long journey the tea leaves make from the plant to your cup makes these steps to a perfect steep well worth it when the result is a beautiful complexity of flavors. Feel free to experiment with the water used, steep time, temperature, amount of tea, and brew vessel until you find the perfect combination that works for you and your unique taste buds. We wish you many joyful steeps!
7. Gascoyne, Marchand, Desharnais. Tea: History, Terroirs, Varieties.
9. Heiss, Mary Lou and Robert. The Story of Tea: A Cultural History and Drinking Guide.