Cold Brew Tea: The Ratio, the Time and the Right Leaves
Use 10 g of loose leaf per litre of cold water — the same dose as hot — and refrigerate for 6 to 12 hours. Strain, then drink within three days. No heat, no bitterness, no sweetener needed.
| Cold brew | Leaf per litre | Fridge time | Result |
|---|---|---|---|
| Sencha | 10 g | 6–8 h | Sweet, marine, no astringency |
| Jasmine Green | 10 g | 6–8 h | The cleanest jasmine you will taste |
| Silver Needle | 10 g | 8–12 h | Melon and hay, almost sweet enough to be a soft drink |
| Bao Zhong | 12 g | 8–10 h | Floral, low caffeine at 28 mg |
| Hibiscus | 15 g | 8–12 h | Crimson, tart, caffeine-free |
| Peppermint | 8 g | 8–12 h | Cool without the cooked-mint note |
Doses scaled from the Teafinity database's hot-brew ratiosteafinity.app
Why cold brew cannot go bitter
This is not a gentler version of hot brewing. It is a different extraction, and the difference is chemistry rather than patience.
The compounds that make tea taste harsh — catechins, and caffeine, which is itself bitter — are far more soluble in hot water than in cold. The compounds that make tea taste sweet and savoury, chiefly amino acids like theanine, along with simple sugars, dissolve well enough at refrigerator temperature. Cold water therefore acts as a filter: given eight hours it takes most of the sweetness and only a fraction of the astringency.
Comparative work on hot versus cold steeping of green, black and white teas confirms that the two routes produce measurably different infusion profiles rather than simply stronger and weaker versions of the same drink.
That is why the usual failure mode disappears. There is no window to miss. Eight hours and sixteen hours differ in strength, not in quality — which makes cold brew the most forgiving technique on this site and the only one where forgetting about it is not a mistake.
The method
- Weigh 10 g of loose leaf per litre. Same ratio as hot. Do not reduce it — cold water extracts less, so cutting the dose gives you tinted water.
- Use a jug, a bottle or a jar. No infuser basket needed; you will strain at the end.
- Add cold, filtered water straight from the tap or the fridge. Never start with warm water "to help it along" — you reintroduce exactly the compounds you were avoiding.
- Refrigerate, covered, 6–12 hours. Green and white at the short end, black and herbal at the long end.
- Strain thoroughly and refrigerate the liquid. Leaving the leaf in past twelve hours does eventually turn it woody.
- Drink within three days.
Do not brew on the counter. Room temperature over eight hours is a different food-safety proposition to a fridge at 4 °C, and there is no flavour benefit to trade for it.
The teas that work — and the ones that do not
Excellent cold:
- Japanese greens. Sencha is the benchmark: sweet, marine, entirely without the grassy edge it gets when brewed too hot.
- Chinese greens. Bi Luo Chun and Dragon Well both come out chestnut-sweet.
- White tea. Silver Needle and White Peony are arguably better cold than hot.
- Light oolong. Bao Zhong and Milk Oolong keep their florals intact.
- Fruit and flower herbals. Hibiscus produces a startling crimson; Peppermint tastes cool rather than cooked.
Poor cold:
- Breakfast blends. English Breakfast and Assam come out thin and dull; they were bred for boiling water and milk.
- Roasted anything. Hojicha and Wuyi rock oolongs need heat to lift the roast.
- Pu-erh. Compressed, fermented leaf simply will not open in cold water.
- Roots and barks. Ginger, licorice and cinnamon need ten minutes of boiling water, not ten hours of cold.
Sweetening, and why you probably will not need to
Cold brew arrives with most of its sugars and amino acids and only a fraction of its bitterness, so the reflex to add sugar usually comes from habit rather than taste. Try it plain first.
If you do sweeten, do it while the tea is still being made rather than at the glass: granulated sugar will not dissolve properly in a cold drink and will sit at the bottom. A small amount of honey stirred into 50 ml of the finished tea, then poured back into the jug, distributes evenly. A twist of citrus peel added for the last hour of steeping does more for a cold-brewed green than any sweetener.
Troubleshooting
- Weak and watery: the dose, not the time. Go to 15 g per litre.
- Woody or vegetal: left on the leaf for more than about sixteen hours. Strain earlier.
- Cloudy: you started with warm water, or you are cold-brewing a black tea. Switch to flash chilling.
- Flat and dull: wrong leaf. Roasted and fully oxidised teas are not cold-brew material.
- Sediment at the bottom: normal for broken leaf. Strain through a finer mesh or decant.
Frequently asked questions
What is the correct cold brew tea ratio?
Ten grams of loose leaf per litre of cold water, which is the same leaf-to-water ratio as a standard hot cup — 3 g per 250 ml — carried up to a jug. Increase to 15 g per litre if you plan to serve it over a lot of ice, since the melt will dilute it as you drink.
How long does cold brew tea take?
Six hours for green and white tea, eight to twelve for black tea and herbal infusions. There is a wide safe window: because cold water extracts astringent compounds so slowly, leaving a green tea in for sixteen hours instead of eight makes it stronger rather than bitter. Overnight is the practical answer for all of them.
Does cold brew tea have less caffeine?
Yes, meaningfully — caffeine is far less soluble in cold water than in hot, so a cold-brewed cup extracts noticeably less of it than the same leaf steeped hot, even over many hours. It is the reason a cold-brewed sencha can be drunk in the evening while a hot one cannot.
Sources
- Venditti, E. et al. — Hot vs. cold water steeping of different teas: Do they affect antioxidant activity?, Food Chemistry 119(4), 1597–1604 — Elsevier. https://doi.org/10.1016/j.foodchem.2009.09.049
Teafinity times every one of these steeps for you
Pick any tea in these guides and the app loads its exact schedule, counts the infusions, rings even in your pocket, and logs the session — free on iPhone and Android.
