Cold Brew Tea Method

Definition:

The cold brew tea method is a preparation technique in which tea leaves are steeped in cold or room-temperature water (typically 4–18°C or room temperature at 20–25°C) for an extended time — usually 4–16 hours, often overnight — without the application of heat. The slow, low-temperature extraction produces an infusion with a distinctly different chemical profile from hot brewing: lower catechin and caffeine extraction, higher relative amino acid concentration, and a characteristically smooth, sweet, and less astringent character.

In-Depth Explanation

The chemistry of cold brew tea is fundamentally different from hot extraction because temperature dramatically affects the solubility and extraction rate of different tea compounds.

Extraction Chemistry Differences

Catechins (astringency/bitterness): Catechin dissolution is strongly temperature-dependent — the gallated catechins (EGCG, ECG) that drive astringency extract slowly at low temperatures. A 12-hour cold brew extracts significantly fewer gallated catechins than a 3-minute hot brew, producing a noticeably smoother, less drying cup.

Caffeine: Caffeine is also less efficiently extracted at cold temperatures. Cold brew tea typically contains less caffeine per volume than equivalent hot-brewed tea, though the exact difference depends on leaf type, ratio, and time.

Amino acids (sweetness/umami): L-theanine and other amino acids are water-soluble across a wider temperature range and extract relatively efficiently even at cold temperatures. The result is that cold brew tea has a higher amino acid:catechin ratio than hot brew — expressed as more sweetness and umami relative to astringency.

Aromatic compounds: Volatile aromatics are better preserved at cold temperatures, as heat causes rapid evaporation. Cold brew green teas in particular can exhibit pronounced fresh, grassy, or floral notes that would dissipate in hot extraction.

Practical Parameters

Water temperature: True cold brew uses refrigerator temperature (4–8°C); room-temperature cold brew (20–25°C) steeps faster and extracts slightly more compounds. Both are distinct from hot brewing.

Steep time: 4–8 hours is a minimum for most teas; 8–12 hours overnight is most common. Over-steeping (24+ hours) in refrigerator temperature rarely causes the same over-extraction problems as hot brewing, but very long steeps can become flat or develop off-notes.

Leaf ratio: Cold brew often requires a higher leaf-to-water ratio than hot brewing (1.5–2× as much leaf) to compensate for slower extraction. A good starting point is 5–6g per 250ml for a cold brew green or oolong.

Best Teas for Cold Brewing

Japanese green teas (especially gyokuro and sencha): The high amino acid content of shade-grown teas shines in cold brew, producing intensely umami, smooth infusions.
Light oolongs: Floral and aromatic notes are well-preserved in cold extraction.
White teas: Produce delicate, sweet cold brews with gentle fruit notes.
Less ideal: Heavily oxidized black teas and roasted oolongs extract slowly at cold temperatures and can taste flat or thin without the heat-driven rapid extraction of their characteristic compounds.

History

Traditional cold water tea: Cold water extraction of tea is historically documented in Japanese mizudashi (水出し) tea preparation — particularly for gyokuro and kabuse teas — likely preceding the Western “cold brew” trend.
Modern cold brew trend: The cold brew tea trend in Western specialty markets grew alongside the cold brew coffee movement of the 2010s, with specialty tea retailers and cafés adding cold brew options.
Research: Scientific interest in cold brew tea’s compound profile has grown since the 2010s, documenting the catechin-reduction and amino acid-preservation effects.

Common Misconceptions

“Cold brew tea is just iced tea made slowly.”

Traditional iced tea is made by brewing hot and then cooling (or flash-chilling over ice). Cold brew is extracted at cold temperature throughout — a fundamentally different extraction process producing a different chemical and sensory profile.

“Cold brew extracts nothing important.”

Cold brew produces a flavorful, chemically active infusion — it simply extracts a different proportion of compounds than hot brewing. For teas with high amino acid content (gyokuro, high-grade sencha), cold brew can produce the most nuanced and pleasant expression of those teas.

Social Media Sentiment

r/tea: Cold brew is a popular topic in summer and in Japanese tea threads; gyokuro cold brew in particular receives enthusiastic discussion.
Japanese tea communities: Mizudashi preparation is a well-known and respected approach; cold brew gyokuro is considered by many enthusiasts as the best expression of the tea.
Specialty tea retailers: Cold brew instructions are increasingly standard in specialty tea product descriptions; dedicated cold brew teas are marketed as summer products.

Last updated: 2026-04

Related Terms

Sources

Venditto, M., et al. (2020). Influence of tea preparation method on the phenolic composition of green tea beverages. Journal of Food Science, 85(3), 641–648. https://doi.org/10.1111/1750-3841.15063. Compares multiple tea preparation methods including cold brew, quantifying how cold extraction changes catechin and amino acid profiles.

Alcazar, A., et al. (2007). Influence of extraction conditions on the total polyphenol content, antioxidant capacity and other quality parameters of green tea. Food Research International, 40(5), 669–677. https://doi.org/10.1016/j.foodres.2007.01.003. Demonstrates how temperature affects polyphenol and catechin extraction, documenting the chemical foundation for cold brew tea’s distinctive properties.