Brewing Mastery
Cold Brew Mastery
Complete cold brew tea guide: ratios, timing, which teas work best, and the science behind why cold water extracts sweetness while avoiding bitterness.
Introduction
{{glossary:cold-brew}} is the most forgiving brewing method and often produces the most approachable cup. By removing heat from the equation, cold water selectively extracts sweet amino acids and moderate caffeine while leaving most bitter catechins and heavy tannins locked in the leaf. The result is a naturally smooth, sweet, low-astringency tea that requires no sugar.
The Science
Catechin extraction is temperature-dependent — their solubility increases exponentially above 70 C. {{glossary:l-theanine}} and other amino acids dissolve readily even at refrigerator temperatures (4 C). Over 8-12 hours, cold water extracts nearly all the amino acids and roughly two-thirds of the caffeine, while extracting only a fraction of the catechins. This chemical selectivity is why cold brew tastes fundamentally different from hot brew that has been cooled.
Basic Method
Add 5-8 grams of loose leaf tea to 1 liter of cold, filtered water in a glass pitcher or bottle. Refrigerate for 8-12 hours (overnight). Strain and serve. The concentrate keeps well for 2-3 days refrigerated.
Tea Selection
Best for cold brew: Gyokuro (intensely sweet, umami), fukamushi sencha (rich, deep green), Taiwanese oolong (fruity, floral), and Assam (surprisingly smooth when cold brewed). Good for cold brew: Chinese green tea, white tea, houjicha, and most black teas. Less ideal: Pu-erh (the earthy depth does not translate as well to cold extraction), and very lightly processed white teas (may be too subtle).
Variations
Sparkling cold brew: Cold brew in still water, then add sparkling water when serving. Fruit-infused: Add sliced citrus, berries, or cucumber to the pitcher for a naturally flavored cold brew. Concentrated: Use 10-12g per liter for a concentrate that can be diluted with water or poured over ice without becoming watery. Rapid cold brew: Japanese iced tea method — brew hot at double concentration onto a cup of ice. Produces a different, brighter character than overnight cold brew.
Japanese Iced Tea (Flash Brew)
Distinct from cold brew: use half the normal water volume at full hot temperature, brew for the standard time, then pour directly over an equal weight of ice. The thermal shock locks in bright aromatics while the ice dilutes to drinking strength. This method produces a more vibrant, complex iced tea than cold brew.