When you use water that is too hot we often call this “burning” the tea. “Burning the tea” means, the hot water has over extracted the polyphenols (tannins) and the tea becomes astringent. This altered flavor prevents the tea from delivering the delicious potential of the leaves! In particular this reference is used with white and green teas.
When you use water that is too cold, you will often under extract the polyphenols (tannins), and your tea will lack its full flavor and character it was meant to create.
It is important to note most botanical teas will not be “burned” as they don’t contain tannins or other elements that could compromise flavor when subjected to and extracted through hot water. Additionally, many botanicals require the hottest water possible in order to fully extract optimal flavor and color.
When brewing tea, the variable water temperature directly ties into the processing method of the tea. What does “processing method” mean? When crafting dried teas from fresh tea leaf, a myriad of steps can be applied to elicit different flavors, which directly determines the category the final product will be. The 6 categories of Camellia sinensis are Green, Yellow, White, Oolong, Black, and Dark teas. The steps taken to create the categories can include dry heat, steam heat, rolling, bruising, and many more. These techniques determine the amount of oxidation that occurs in the leaf.
Oxidation is a natural enzymatic reaction that is similar to the browning of a sliced apple or freshly chopped basil leaves. For tea, it is the biochemical process that changes freshly picked leaves from green to yellow, amber to red, and finally brown. Heat halts the oxidation process. Though oxidation is not desired in culinary applications, controlling the amount of oxidation is a significant goal in tea processing.
When manipulating the percentage of oxidation in tea leaves, the tea tannins are being altered. Tannins are also referred to as antioxidants or polyphenols, which are secondary plant metabolites. Typically, plants produce secondary metabolites to protect against UV radiation or pathogens. Recent epidemiologic study publications suggest consuming polyphenols could benefit one’s health in numerous ways.
Here we have an outline of the levels of polyphenol types and how we typically see these structures represented in the tea categories. The polyphenols depicted in the chart include: Fresh Tea Polyphenols, Theaflavins, Thearubigins, and Theabrownins. We see on the spectrum, the darker we go, the differently the polyphenols develop. Each class of polyphenols is touted to have different benefits, so hypothetically, one could select a tea with the greater potential for separate healthful gains.
