The process of making delicious chai involves understanding the science behind each step and how it relates to the taming of tannins in the tea. Tannins are water-soluble polyphenols found in various foods and contribute to flavor, bitterness, and astringency. Black tea contains nearly 600 aroma compounds, three times as many as green tea, due to its processing, which includes crushing, full oxidation, and roasting. This process also creates a large number of tannins, which must be balanced with other ingredients to prevent the tea from becoming overly bitter.

One way to balance the tannins is by adding milk, as the whey protein in milk unravels and binds readily with the tannins as they leach out of the tea. Frothing the tea serves a purpose as well, as suffusing oxygen into the chai softens the flavor of the tannins. Adding sugar while boiling further mellows the bitter notes, and a spice mix (such as ginger, cinnamon, cloves, pepper, or fennel) provides new flavor notes to the brain through the sense of smell.

When making chai at home, it’s important to watch out for fresh ginger’s curdling effect on milk and the need to bring the mix to a boil to deactivate the zingipain enzyme. Cardamom pairs well with chai because its flavor compounds dissolve better in fat than in water, and tannin-heavy spices like cinnamon and cloves should be used sparingly. Chaiwalas use a powdered spice mix that allows for increased surface area and quick release of aromas, adding it towards the end to keep the fragrances fresh and enticing.