The Steeping Process

• Water temperature and steeping time matter more to tea flavor than adding lemon to the water. Black tea releases more flavor if you pour in water from your teakettle that is at a full boil and steep it for about 1 minute. However, green tea tastes better when you let the boiling water sit in the kettle for 10 to 15 seconds before pouring and then steep the tea for about 5 minutes.

Tannins in Tea

• Processing tea leaves into tea changes their tannins from substances that deter bacteria and fungi that would otherwise eating the plants to substances that give tea color and flavor. When the leaves are dried and fermented, they turn into dark, black teas. Green teas, with lighter, greenish-yellow colors, have leaves that are dried but not fermented, resulting in tannins that are weaker in both flavor and color than those in dark teas.

Lemon and Tannins

• In addition to adding flavor and color to tea, tannins are what scientists call acid-base indicators, changing colors when they are in either an acidic or an alkaline environment. In other words, tannins act like a litmus dye, which comes from lichens, another acid-base indicator. When you add acidic lemon juice to tea, the tannins react by turning yellow. If you were to add an alkaline substance, such as baking soda, the tea would turn a darker reddish brown.

Additional Effects of Lemon

• In addition to adding flavor to tea, lemon juice helps iced tea stay clear. Tannins dissolve in hot water but lose their solubility and drop out of the water in small, solid particles once the water cools. Because tannins stay more soluble in an acidic environment, lemon juice keeps the particles suspending in the water. The effect occurs whether you add lemon juice to the tea when you first place it in the refrigerator or you add it after the tea becomes cloudy.