Cold Brew Summer
Do you know what typically causes the bitter or astringent flavour in your cup of tea?
Tea leaves contain tannins - polyphenols that are high in antioxidants, and caffeine - a stimulant that energizes the mind and body, both of which can translate as bitterness and astringency. Tea leaves also contain L-theanine - an amino acid that provides an overall umami (savory taste), sweet complexity and calming effect on the mind and body. When paired with caffeine, L-theanine can improve cognitive function and increase overall alertness.
If tea is brewed at a high temperature, tannins and caffeine will dissolve into the water and can make the tea taste slightly bitter. However, if tea is prepared and steeped slowly at a low temperature, the tannins and caffeine will hardly dissolve into the water, and L-theanine, the amino acid, can be more present.
With the cold water brewing method, the cold water draws out, or pulls the flavor from the leaf as opposed to hot water, used in traditional brewing which pushes the flavor from the leaf. This is why tea prepared with cold water is rarely bitter or astringent, and instead has a mild, naturally sweet, yet rich flavor, portraying the inherent nature of tea leaves.