How to Make Cold Brew Tea in the Fridge
Put about 8–10 g of loose-leaf tea, or 4–5 tea bags, in a clean jug with 1 litre of cold drinking water, cover it and leave it in the fridge for 8–12 hours (6–8 for green or white tea), then strain. It comes out smooth and less bitter than hot-brewed iced tea.
Steep it in the fridge, not on a sunny windowsill: Ohio State University Extension says sun tea never gets hot enough to kill bacteria and sits warm for hours. Keep the finished tea chilled and drink it within a couple of days. Green and black cold brew still contain caffeine; herbal ones such as rooibos don't.
Ingredients
- 8–10 g loose leaf (about 3 tbsp) or 4–5 bags per litre Loose-leaf tea or tea bagsGreen, black, white or oolong. Use a little more for herbal teas, which are bulkier. Large-leaf teas need more by volume than fine ones
- 10–15 g (about 4–5 tbsp) or 5–6 bags per litre Herbal alternative (caffeine-free)Rooibos, peppermint, hibiscus, lemon verbena or fruit blends all cold brew well
- 1 litre (4 cups) Cold drinking waterTap water you would happily drink, or filtered
- 1–2 tbsp per litre, to taste Simple syrup or honey (optional)Sugar dissolves poorly in cold tea, so stir in a syrup made with a little hot water
- A few slices or sprigs Lemon slices, mint or fruit (optional)Add when serving
Equipment
- Clean glass jug or large jar with a lid (about 1.2 litres)
- Fine sieve, or a cold brew jug with a built-in filter
- Spoon
- Bottle or jug with a lid for storing
Method
Start with clean equipment
Wash the jug, lid and sieve in hot soapy water and rinse them well. Ohio State University Extension advises washing, rinsing and sanitising tea-making equipment regularly.1
Add tea and cold water
Put 8–10 g of loose tea (about 3 tablespoons) or 4–5 tea bags into the jug and pour in 1 litre of cold drinking water. For herbal tea, use 10–15 g or 5–6 bags. Stir once so all the leaves are wet.
Cover and steep in the fridge
Put the lid on and put the jug straight into the fridge. Steep green and white tea for 6–8 hours, and black, oolong and herbal teas for 8–12 hours or overnight. Ohio State University Extension suggests six hours to overnight in the fridge, depending on how strong you like it.1
Taste, then strain
Taste it: cold brewing is forgiving, so a few extra hours won't make it harsh the way a long hot steep would, but green tea can turn grassy. When you like it, strain out the leaves or lift out the bags. Don't squeeze the bags, which adds bitterness.
Sweeten if you like
Sugar dissolves poorly in cold tea. Stir 1–2 tablespoons of sugar into the same amount of hot water to make a quick syrup, let it cool, and add it to taste. Honey also mixes in better if you loosen it with a spoonful of warm water first.
Keep it cold and drink it soon
Pour the tea into a clean bottle or jug, cover it and keep it in the fridge, which the Food Standards Agency says should be set between 0 and 5°C (32–41°F). We treat it like other leftovers, which the FSA says to eat within 48 hours.2
Serve
Pour over ice with lemon slices, mint or a few berries. If the tea is very strong, top it up with cold water or sparkling water rather than steeping it for less time next time.
Safety
- Steep in the fridge, not in the sun: sun tea stays below about 54°C (130°F), too cool to kill bacteria, and sits warm for hours1
- Throw it out if it turns thick, syrupy or stringy; Ohio State Extension links this to a ropy bacterium found in soil and water1
- Keep the jug in a fridge set at 0–5°C (32–41°F) and drink the tea within about 48 hours2
- Green and black cold brew contain caffeine. The FDA cites 400 mg a day for most adults; the NHS advises no more than 200 mg a day in pregnancy3,4
- US dietary guidelines, quoted by the FDA, say children under 2 shouldn't have caffeinated drinks; use a herbal tea for young children3
Variations
Cold brew black tea with a sliced ripe peach in the jug, then strain both out. Drink within the same 48 hours.
Use 10 g of dried hibiscus and a handful of fresh mint per litre. It turns deep red, tastes sharp like cranberry and is caffeine-free.
Brew the tea at double strength (16–20 g per litre), then mix half and half with chilled sparkling water when you serve it.
Add a few strips of unwaxed lemon peel to green tea for the last 2 hours of steeping, and a squeeze of juice when serving.
Does it actually work?
Cold brew is a way of making tea, not a health treatment. Cold steeping pulls compounds out of the leaves more slowly than hot water and damages fewer of them: in one laboratory study a long cold infusion ended up with higher levels of the antioxidant compounds measured than a hot one. That makes a smoother drink, but nobody has shown it makes a healthier one in people.
For green tea itself, NCCIH says studies on cancer are inconsistent, weight effects are modest at most, and lower heart disease risk has been seen in Asian but not Western populations. It reports no safety concerns for green tea drunk as a beverage by adults, apart from its caffeine. Rooibos is caffeine-free; see our rooibos entry for what its small trials found.6,7,5
Questions people ask
How long should cold brew tea steep?
About 6–8 hours for green or white tea and 8–12 hours for black, oolong and herbal teas, in the fridge. Ohio State University Extension suggests six hours to overnight, depending on how strong you like it.
Is it safe to cold brew tea on the counter?
It is safer in the fridge. Tea left at room temperature or in the sun sits warm for hours, which gives bacteria from the water or leaves a chance to multiply. Steep it in the fridge from the start and keep it there.
Does cold brew tea have less caffeine?
It still has caffeine if it is made from green, black, white or oolong tea, and the amount depends on the leaf and the steeping time. We found no reliable figure for home cold brew; the FDA puts hot-brewed tea at about 37 mg (green) to 71 mg (black) per 12 fl oz. Herbal teas like rooibos have none.
How long does cold brew tea last in the fridge?
We suggest drinking it within 48 hours, the same as the Food Standards Agency's advice for leftovers, and keeping it at 0–5°C. Throw it out sooner if it smells off, looks cloudy and slimy, or turns thick or stringy.
Can I use tea bags for cold brew?
Yes. Use about 4–5 standard bags per litre of cold water and steep for the same times as loose tea. Lift them out rather than squeezing them, which can make the tea bitter.
Sources (7)
- University extension Ohio State University Extension, Live Smart Ohio. Is Sun Tea Safe? 2011.
- Regulator Food Standards Agency. How to chill, freeze and defrost food safely. GOV.UK.
- Regulator U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much?
- Health service NHS. Foods to avoid in pregnancy.
- Scoping review Afrifa D, Engelbrecht L, Eijnde BO, Terblanche E. The health benefits of rooibos tea in humans (Aspalathus linearis): a scoping review. J Public Health Afr. 2023.
- Laboratory study Lantano C, Rinaldi M, Cavazza A, Barbanti D, Corradini C. Effects of alternative steeping methods on composition, antioxidant property and colour of green, black and oolong tea infusions. J Food Sci Technol. 2015.
- Regulator/health agency NCCIH. Green Tea: Usefulness and Safety. National Center for Complementary and Integrative Health (last updated February 2025).
Educational only. Patch-test anything new on your skin, and stop if it irritates.
Reader notes
Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.