Cold-brewing tea: the Cold Brew guide
Written by Dian VAULTIER·
In Brief
- Cold brewing, or cold brew, offers a radically different approach to preparing tea, based on slowness rather than heat.
- The solubility of tea compounds varies greatly according to water temperature.
- HOLLIN tea sommelier expertise: cold brewing explained by a purist Tea House, with no added flavourings, based in Sartrouville (Île-de-France) and shipping its fine teas worldwide.
Thetime Cold brewing, or cold brew, offers a radically different approach to preparing tea, based on slowness rather than heat. By leaving the leaves to infuse in the refrigerator for several hours, this method favours the extraction of gentle amino acids, such as L-theanine, over the tannins responsible for astringency. The result is an unusually rounded liquor, particularly well suited to hot days and the most delicate teas.
The biochemical principle of cold extraction
The solubility of tea compounds varies greatly according to water temperature. Amino acids, including L-theanine, dissolve efficiently even at low temperatures, while the most astringent catechins and caffeine require greater heat to be fully extracted.
Thetime Cold brewing takes advantage of this difference in kinetics: by allowing time to compensate for the absence of heat, it promotes selective extraction that favours sweetness over bitterness, while reducing the final caffeine content of the drink.
The brewing protocol, step by step
Use approximately three to four grams of whole-leaf tea for 250 millilitres of cold filtered water. Place the leaves directly in a carafe or glass container, with no need for a fine filter, then leave to infuse in the refrigerator for between four and eight hours, depending on the desired intensity.
Which teas are best suited to cold brew
The green teas Japanese teas, rich in L-theanine and low in tannins, are among the best candidates for this method, revealing remarkably pure umami and vegetal notes without any residual bitterness.
The oolongs Lightly oxidised teas also develop interesting profiles when time cold brewed, with floral and fruity notes enhanced by the slowness of the extraction, while black teas highly tannic teas are generally less well suited to it.
The purist selection of HOLLIN
At the HOLLIN du Goût counter, 22 avenue de la République, 78500 Sartrouville, open Monday to Saturday from 10h to 20h, each season we advise you on the lots best suited totime cold brewing, particularly during the warmer months, when this method enjoys a rightful resurgence of interest.
Our tea masters can also guide you towards filtering carafes suited to this practice, available within our range of tea objects.
The slow chemistry of cold water
Cold extraction does not merely slow thetime, it alters its selectivity. The most astringent catechins and some of the caffeine dissolve poorly below ten degrees, while amino acids, including theanine, and soluble sugars readily migrate into the water. The result is a smooth, sweet liquor, free from bitterness, whose umami unfolds without a tannic counterpoint.
Time replaces temperature. Allow eight to twelve hours in the refrigerator for ten grams of leaves per litre of low-mineral water. Japanese green teas teas, lightly oxidised oolongs teas and white teas are remarkably well suited to this method. Full-bodied black teas teas lose some of their structure, without becoming unpleasant.
Method, storage and variations
Use a clean glass carafe, add the leaves loose rather than placing them in a tight filter, then strain when serving. Water that is cold from the outset, never heated and then cooled, preserves the vibrancy of the whole. The drink will keep for twenty four to forty eight hours when refrigerated in a covered container, as the absence of pasteurisation demands impeccable hygiene.
A few variations are worth trying. Kori dashi, in which the leaves are covered with ice cubes and left for an hour in the refrigerator, produces a liquor extremely concentrated in umami, served in very small quantities. A time of green tea cold with fresh lemon zest added, without sugar, accompanies summer meals with a clarity few drinks can match. Our teas green teas and our Matcha are particularly well suited to these preparations.
To continue this exploration beyond the screen, step through the door of the HOLLIN du Goût counter, our contemporary Asian grocery located at 22 avenue de la République in Sartrouville. Here, the leaves are opened, smelled and discussed, and every recommendation is tailored to your water, your teapot and your time of day.
Frequently Asked Questions (FAQ)
- How long can cold-brewed tea be kept?
- Once strained, cold-brewed tea can be kept in the refrigerator for a maximum of twenty-four to forty-eight hours, in an airtight container, to preserve its aromatic freshness and prevent any bacterial growth linked to the absence of heat during preparation.
- Does cold brewing contain less caffeine than hot brewing?
- As a general rule, yes, because caffeine is extracted more effectively at high temperatures. Thetime cold infusion, relying on time rather than heat, produces a drink that is generally less stimulating, although the exact content varies according to the chosen brewing time and the grade of tea used.
- Can tea bags be used for cold brewing?
- It is possible, but whole leaves generally offer a higher-quality result, as they unfurl more slowly and evenly throughout thetimebrewing period. Tea bags, which often contain finer fragments, may release more pronounced astringency even when cold brewed.