Updated: Mar 15, 2022
One often overlooked aspect of tea brewing is allowing room for the leaves to expand. The mechanics of tea brewing are simple: when the leaf surface comes into contact with water, it begins absorbing water and releasing chemical compounds carrying flavor, aroma, and health benefits into your tea. But as the leaves absorb water, they expand. How much? Depends on the tea; some leaves expand to double their dry size, some four times, and some even ten times.
This is why we recommend against the ‘ball’ style infuser, or any small or novelty infuser - they don’t allow room for the leaves to expand. If the leaves are blocked from expanding, the whole surface area of the leaf will not be exposed. Leaf surface area contact with water is a fundamental in tea brewing. For example, teas with more ‘broken’ leaves brew faster, because more of their surface area is exposed to water from the beginning. This is what makes Japanese steamed green teas more prone to bitterness when using boiling water or long brew times. It’s also the principle behind tea used for teabags.
If your leaves are packed in and can’t expand, you’re only getting flavor out of the edges of the leaves exposed to water. This can make the tea simultaneously weak and ‘edgy’ in flavor and character. But it’s also effectively a waste of leaves. Since parts of the leaf are not contributing, the result is like brewing with less leaf overall.
Small infusers aren’t the only danger zone: brewing with a very small pot and using too much leaf for the pot size can have the same effect. This is why we provide guidelines for different pot sizes. It’s also why we carry our own infuser basket - so you can avoid this issue altogether!
Understanding brewing mechanics like surface area also helps explain why techniques like ‘Waking Up the Leaves’ are important. For teas that are tightly rolled, if your first brew is under a minute, the leaves won’t have opened up very much, resulting in the same weak or edgy flavor described above. Discarding a quick brew first helps get the leaves to open up, exposing more surface area for the real thing.
Tea brewing is an art, an intuitive process that will guide you in deciding how much leaf to use for a given pot, what pots work best for what teas, what water temperature to use, and how long to brew for. But understanding the science behind it will save you from a lot of ‘weak tea’ early on.