Cold Brew Tea: A Complete Guide to Making Tea in Cold Water

Cold brew tea is leaf steeped in cold or room-temperature water for hours rather than minutes. The slow extraction pulls out sugars and amino acids first and leaves most of the bitter catechins behind, so the result is sweet, clean and low in astringency. Use about 5 g of leaf per 500 ml, refrigerate for four to eight hours, and strain.

Why cold extraction tastes different

Extraction is a function of temperature and time. Hot water dissolves compounds quickly but indiscriminately, which is why a two-minute hot steep can already be bitter. Cold water dissolves the same compounds far more slowly, and the easily soluble ones, sugars and amino acids, come out long before the bitter catechins do.

The practical result is a tea that tastes sweet and clean and almost never bitter. It is also lower in caffeine in absolute terms, though not caffeine-free, because caffeine is water-soluble and does come out over hours. A cold brew left overnight can carry a reasonable amount.

What cold brewing does not do is develop aroma. The volatile compounds that make a hot cup smell of orchids or chestnuts need heat to be released, and a cold brew is quiet on the nose. It makes up for that in texture and refreshment rather than fragrance.

The method

• Use 5 to 7 g of leaf per 500 ml, depending on the tea type.
• Use filtered water. Chlorine is more noticeable in a cold brew than in a hot one.
• Put the leaf in a bottle or jug, add water, and refrigerate.
• Leave it for the time in the chart, tasting at the short end the first time.
• Strain through a fine sieve, pressing gently. Do not squeeze the leaf.
• Drink within 24 hours, or keep it refrigerated and finish within two days.

Room-temperature brewing works too and is faster, roughly two to four hours for most teas. It gives slightly more aroma than fridge brewing but is also more prone to going off if you leave it too long. In a warm kitchen, fridge brewing is safer.

Do not use boiling water and then chill. That is hot brewing followed by cooling, which extracts the bitter compounds and then makes them cold. It is a different drink and usually a worse one.

Where the method fails

Cold brewing is poor for teas whose appeal depends on aroma. A high-mountain oolong or a fresh Longjing loses most of what makes it special, and a cheap tea with a strong fragrance may actually taste better cold than hot because the aroma does not have to stand on its own.

It is also poor for teas with a lot of dust. Cold water does not dissolve the fine particles, so they stay suspended and the brew looks cloudy. Strain through a paper filter if clarity matters.

And it is slow to correct. If a hot brew is too strong you can add water; a cold brew that has gone too far has already extracted what it is going to extract. Taste at the early end of the range the first time you use a new tea.

Serving and variations

Serve it over ice, but use ice made from the same tea rather than water, or the drink will dilute as it sits. A simpler alternative is to brew it stronger and pour over ordinary ice, accepting the dilution.

Cold brew accepts additions better than hot tea does, because there is less bitterness to mask. Citrus peel, a slice of ginger or a few mint leaves work. Sugar is usually unnecessary, and milk curdles badly in an acidic cold brew.

The method also works well for blending. Cold-brewed green tea with a little honey and lemon is a common summer drink in southern China, and cold-brewed roasted oolong over ice is a good introduction for drinkers who find hot oolong too intense.

Health, in proportion

Cold brew contains caffeine, and while the concentration per millilitre is usually lower than a hot brew, a large bottle can still deliver a meaningful dose. It also contains fewer catechins, which is why it tastes less bitter. Neither fact makes it a health drink, and no tea treats disease.

Why it suits some teas and not others

Cold brewing favours teas whose appeal is sweetness and texture rather than aroma. A green tea with a soft, sweet profile does well. A high-mountain oolong whose whole character is a high floral note does not, because that note never appears. A roasted oolong is a middle case: the bake and the mineral note survive, and the result is pleasant but not remarkable.

A practical rule is to cold brew the tea you would not mind drinking quietly. If a tea’s main virtue is a shout, cold water will not carry it.

Cold brew and the question of freshness

Cold brewing is unusually forgiving of tea that is slightly past its best. Because the extraction favours sugars and amino acids, a tea that has lost its aroma to age can still make a pleasant cold brew, where a hot brew of the same leaf would taste flat and papery.

That makes it a useful way to use up the end of a tin, particularly for green tea that has been open for a year. It is also a sensible way to handle a tea that turned out to be disappointing hot, provided the problem is a lack of aroma rather than a processing fault.

What it will not fix is a tea with a scorched or sour note. Those compounds dissolve in cold water just as readily, and the brew will carry the fault.

Frequently asked questions