the chemistry of tea: how four key variables unlock flavor
every time you brew tea, you’re doing a controlled extraction. hot water pulls hundreds of compounds out of the leaves and into your cup. these compounds—amino acids, polyphenols, caffeine, aromatic molecules—are what create tea’s taste, aroma, color, and even mouthfeel.
understanding the main variables that influence this process helps you control not just strength, but the character of the tea you drink.
1. water temperature
temperature determines which compounds dissolve first—and how many of them make it into your cup.
amino acids (like l-theanine) dissolve readily, even in cooler water. these are responsible for tea’s sweetness, umami, and smooth texture. lower temperatures highlight them.
catechins and tannins (polyphenols) need hotter water to fully dissolve. these compounds give tea its bitterness, dryness, and brisk mouthfeel.
caffeine is also more soluble at higher temperatures, which is why hotter brews often feel stronger and more stimulating.
higher water temperature means more catechins and caffeine = bolder, more astringent tea.
lower water temperature means more amino acids relative to tannins = softer, sweeter tea.
2. steeping time
time is about sequencing. different compounds extract at different rates:
aromatic molecules (floral, grassy, fruity notes) come out first—this is why even a quick infusion smells amazing.
amino acids release early as well, contributing sweetness and body.
caffeine and polyphenols come next, building strength and slight bitterness.
tannins are last, and too much time can make them dominate the cup.
shorter infusions favor aromatics and sweetness. longer infusions increase body and bitterness, eventually overwhelming the more delicate flavors.
3. tea-to-water ratio
this variable controls concentration rather than chemistry, but it still changes the sensory experience.
with more tea leaves in the same amount of water, you reach a higher saturation of compounds faster—resulting in a dense, full-bodied tea that doesn’t require a long steep.
with fewer leaves, you need longer time to reach a similar concentration, which risks pulling more tannins than you might want.
you cannot increase steep time to fully compensate for a low leaf to water ratio. a higher tea:water ratio provides a fuller flavor. you can increase the “strength” of a brew by brewing longer, but there is no replacement for using more tea
in other words, ratio lets you create a strong tea without over-extraction.
4. water quality
water isn’t just a neutral medium—it has its own chemistry that interacts with the tea.
hard water (with high calcium/magnesium) can bind to polyphenols, muting aroma and making tea look cloudier or duller.
chlorine can interfere with delicate aromas, giving tea a flat or even “swimming pool” note.
soft, low-mineral water allows the full spectrum of compounds to shine through, especially the aromatic and sweet ones.
this is why the same tea can taste bright and fragrant in one city and dull in another—the water composition changes the extraction chemistry.
how these variables work together
these four variables form a system. for example:
using more leaf at a lower temperature and shorter time can produce a thick, silky, umami-rich brew.
using hotter water for a short time can highlight aromatics but still give you caffeine punch.
using very soft water makes every other adjustment more noticeable—you’ll taste the difference between a 2-minute and 3-minute steep much more clearly.
when you start to think in terms of compounds rather than just “strong” or “weak” tea, brewing becomes a tool for shaping flavor exactly the way you want it.