Cold Brew

Cold brew is coffee made by steeping coarsely ground coffee in cold or room-temperature water for many hours, usually 12–18, then straining it. No heat is involved at any point. What you get is a smooth, mellow, naturally sweet coffee with lots of chocolate and caramel and very little sharpness, and it keeps in the fridge for days. It’s also about the easiest coffee there is to make: a jar, some coffee, some water and patience. Below you’ll find my recipe, the numbers, the fixes and every way of making it, from a jam jar to a Kyoto drip tower.

The short version

• Use 100 g of coarse coffee to 800 g of cold water (a 1:8 ratio). Weigh it if you can.
• Steep it in the fridge for 12–18 hours. For a stronger brew, add more coffee rather than steeping longer.
• Strain it twice: through a sieve first, then a paper filter.
• Dilute about half and half with water or milk, and serve over ice.
• Keep it sealed in the fridge and use it within about a week.

What’s the difference between cold brew and iced coffee?

People use the names loosely, but they’re two different drinks. Cold brew never touches hot water. Iced coffee is brewed hot and then chilled.

	Cold brew	Iced coffee (flash brew)
Water	Cold or room temperature	Hot, brewed straight onto ice
Time	12–18 hours	3–5 minutes
Taste	Smooth, mellow, chocolatey, low bitterness	Bright, fruity, aromatic
Acidity	Tastes less sharp	Keeps more lively acidity
Keeps	About a week as a concentrate	Best drunk straight away
Best beans	Medium to dark roasts	Light to medium roasts

If you want the bright, fragrant version, see Japanese iced coffee.

What do you need to make cold brew?

Almost nothing you don’t already own.

You’ll need	Ideal	If you don’t have one
Something to steep in	A 1 litre glass jar with a lid	Any jug, bowl or French press (cover it with a plate)
Coffee	Whole beans, ground extra coarse just before brewing	Pre-ground “cafetière” coffee works; avoid fine espresso grind
A grinder	A burr grinder	Ask your roaster to grind it for cold brew
A scale	A kitchen scale	100 g of coffee is about 16 level tablespoons
Something to strain with	A fine sieve, then a paper filter	A clean tea towel, a muslin cloth or a nut-milk bag
Water	Cold, filtered water	Tap water is fine if it tastes good
A fridge	Yes	A cool spot at room temperature, for a shorter steep

How much coffee and water do you need for cold brew?

My go-to is 100 g of coffee to 800 g of water, a ratio of 1:8. It makes a concentrate you dilute about half and half to serve. The grounds soak up a fair bit of water, so 800 g in gives you roughly 600 ml of cold brew out.

Style	Ratio	Coffee per 1 litre of water	How to serve
Strong concentrate	1:4 to 1:5	200–250 g	Dilute about 1 part coffee to 2 parts water or milk
All-rounder (my default)	1:8	125 g	Dilute about half and half
Ready to drink	1:12 to 1:16	60–85 g	Pour over ice as it is

Scaling it for your jar:

Jar size	Coffee (1:8)	Water	Makes (approx.)
500 ml	60 g	480 g	360 ml concentrate
1 litre	100 g	800 g	600 ml concentrate
2 litres	200 g	1,600 g	1.2 litres concentrate

Weigh both the coffee and the water: scoops of coarse coffee vary a lot. The brew ratio calculator will scale any of these for you.

What grind size is best for cold brew?

Go extra coarse, like cracked pepper or coarse sea salt.

A long steep needs a coarse grind. Fine coffee extracts too far over 12+ hours, tastes bitter and muddy, and clogs your filter so straining takes forever. If your cold brew tastes weak, use more coffee before you grind finer.

How long should cold brew steep?

12–18 hours in the fridge is my default; published recipes range from 12 to 24 hours (Toddy and Complete Home Barista both say 12–24). Cold water extracts slowly, but not as slowly as those times suggest: a 2017 study in Scientific Reports by Megan Fuller and Niny Rao found that caffeine and chlorogenic acid reached their final concentrations between 6 and 7 hours in every cold brew they tested, whatever the grind. Steeping past that doesn’t add more of them. Many people find very long steeps taste woody or bitter, so taste as you go and strain when you like it.

Where	Steep time	Notes
Fridge	12–18 hours	My default: clean, smooth and cold the whole time
Room temperature	10–14 hours	Faster and a touch fuller; strain and refrigerate straight away
Overnight shortcut	8–10 hours	Lighter; use a 1:6 ratio to make up for it

Want it stronger? Add more coffee rather than steeping longer. The extra hours add little once extraction has levelled off.

How do you strain cold brew without sludge?

Straining is where most home cold brew goes wrong. The trick is to do it in two stages:

1. First, a coarse strain. Pour through a fine sieve, a French press plunger or a nut-milk bag to remove the bulk of the grounds. Don’t squeeze or press the grounds hard; it pushes bitterness and fines into the coffee.
2. Then, a fine strain. Pour it through a paper coffee filter (a V60 or any filter cone works) to catch the silt. It’s slow, so leave it to drip while you do something else.

The paper step is optional, but it’s the difference between cloudy cold brew that turns muddy in a day and clean cold brew that keeps.

Why does my cold brew taste weak, bitter or sour?

Problem	Likely cause	Fix
Weak, watery	Too little coffee, or diluted too much	Use more coffee (towards 1:5) or dilute less
Bitter, woody	Steeped too long, or grind too fine	Strain at 12–16 hours and grind coarser
Sour, thin	Steeped too short, or grind too coarse	Steep a few hours longer, or grind slightly finer
Cloudy or muddy	Fines got through, or the grounds were squeezed	Strain through paper and don’t press the grounds
Flat, stale or papery	Old coffee, or kept too long	Use fresh beans and drink it within a week
Tastes of the fridge	Open container	Steep and store with a lid on
Takes ages to strain	Grind too fine	Grind coarser, and strain through a sieve before the paper

Common cold brew mistakes

• Grinding too fine. It turns bitter and clogs the filter. Go extra coarse.
• Steeping for days. Extraction levels off within hours, so more time doesn’t add strength. Strain when it tastes right, usually within 24 hours.
• Squeezing the grounds. Tempting, but it adds bitterness and silt. Let it drain.
• Using hot water to speed it up. Then it isn’t cold brew, and it tastes completely different.
• Leaving it out after straining. Get it into the fridge straight away.
• Diluting the whole batch at once. Keep it as a concentrate and dilute each glass; it keeps better.

What’s the best coffee for cold brew?

• Medium to dark roasts are the easy win. Cold brew brings out chocolate, caramel and nutty flavours, and darker roasts give it a rich, rounded taste.
• Origins that taste chocolatey and nutty suit it well, such as many coffees from Brazil, Colombia and Guatemala.
• Light roasts can be lovely, but different. Fruity Ethiopian coffees make a sweeter, more delicate cold brew; use a slightly longer steep or a stronger ratio.
• It doesn’t need your most expensive beans. Cold brew is forgiving, so a good everyday coffee works brilliantly. It does need to be reasonably fresh: within about a month of the roast date.
• Decaf works perfectly for an evening glass.

Cold brew methods and variations

There’s more than one way to brew coffee cold. Here are the main ones, from easiest to most specialist:

• Jar or jug (immersion). The method on this page: coffee and water in a jar, steep, strain. Cheap, easy and perfect for big batches.
• French press. The same steep, but the plunger does the first strain for you. Put the lid on without pressing, then press slowly after 12–18 hours.
• Cold brew bottles. A bottle with a built-in mesh filter, such as Hario’s Mizudashi. Add coffee and water, steep in the fridge, lift out the filter and pour. Very tidy for a litre or less.
• Toddy-style systems. A brewing bucket with a felt filter and a plug in the bottom. You steep a big batch of concentrate, then pull the plug and let it drain into a carafe. Great for strong concentrate in bulk.
• Cold brew concentrate. Brewing extra strong (1:4 to 1:5) to save fridge space and dilute later. Ideal for iced lattes.
• Kyoto slow drip. A tall glass tower that drips ice-cold water onto the coffee, often around one drop per second, over several hours. It’s percolation rather than steeping, and makes a very clean, intense, almost syrupy coffee. Beautiful to watch.
• Nitro cold brew. Cold brew infused with nitrogen and poured from a tap like stout, giving a creamy texture and a cascading head without any milk. At home, people use a cream whipper with nitrous-oxide chargers, which gets you close.
• Ultrasonic cold brew. A newer, experimental approach. Researchers at the University of New South Wales used ultrasound to make a coffee comparable to a 24-hour cold brew in about one to three minutes (published in 2024).
• Japanese iced coffee (flash brew). Not cold brew at all: hot coffee brewed straight onto ice. I’ve included it because people mix them up, and it’s the one to choose if you want brightness rather than smoothness.

Cold brew drinks worth trying

• Iced latte. Fill a glass with ice, add 100 ml of 1:8 cold brew and top up with about 100 ml of cold milk or oat milk.
• Coffee tonic. Fill a tall glass with ice and about 150 ml of tonic water, then slowly pour 50 ml of cold brew on top so it layers. A twist of orange or lemon peel is lovely.
• Cold foam. Froth cold milk (skimmed foams best) with a handheld frother until thick, and spoon it over a glass of cold brew.
• Sweet and creamy. Stir a spoonful of sweetened condensed milk into cold brew over ice, a nod to Vietnamese iced coffee.
• Cold brew ice cubes. Freeze some cold brew in an ice tray, so your drink gets stronger rather than watery as the ice melts.
• Hot cold brew. Yes, really: top cold brew concentrate with freshly boiled water, half and half, for a quick, smooth hot mug.

How long does cold brew last?

Cold brew keeps better than most coffee, but it doesn’t last forever.

How it’s stored	Keeps for about	Notes
Concentrate, sealed, in the fridge	7 days (up to 2 weeks)	Best in the first week; the flavour slowly fades
Diluted with water, in the fridge	2–3 days	Dilute each glass as you go instead
Mixed with milk	1 day	Follow the milk’s use-by date
Frozen as ice cubes	A few months	Great for iced drinks
Left out at room temperature	A couple of hours	Refrigerate as soon as it’s strained

Use a clean glass jar with a lid, and throw it away if it smells sour, looks cloudy or grows anything. Keeping cold brew in the fridge from the moment you start steeping to the last glass reduces the chance of bacteria growing, which is another reason the fridge is my default.

General guidance only, not food-safety or medical advice.

Is cold brew less acidic, and does it have more caffeine?

Less acidic: it tastes that way, but it’s not dramatically different. A 2018 study in Scientific Reports by Niny Rao and Megan Fuller compared cold and hot brews of the same coffees. The pH was similar, between 4.85 and 5.13, but the hot brews had more total (titratable) acidity and more antioxidant activity. So cold brew genuinely tastes smoother and less sharp, but claims that it’s “67% less acidic” aren’t backed by that research. If acidity bothers your stomach, cold brew may feel gentler, but it isn’t acid-free.

More caffeine: only if you drink it strong. Cold brew uses a lot of coffee, so an undiluted concentrate packs a punch. Diluted half and half, a 1:8 cold brew lands in roughly the same range as a mug of hot filter coffee. Published figures vary widely because everyone’s recipe is different, so judge it by how strong you make it.

General guidance only, not medical advice.

Which cold brew maker should I buy?

Honestly, you may not need one. A jar and a sieve make brilliant cold brew. If you make it often, here’s what each option is good for:

Maker	Best for	Trade-off
A jar plus a filter bag	Cheap, any batch size	Straining is a bit messy
French press	Small batches, if you already own one	Ties up your press for a day
Cold brew bottle	A tidy litre in the fridge	Small batches only
Toddy-style system	Big batches of concentrate	Bulky; filters need replacing
Kyoto drip tower	A beautiful, very clean coffee	Expensive, fragile, slow to set up

Whatever you choose, look for a lid that seals (fridges are smelly places), a filter fine enough to keep silt out, and something easy to clean.

A short history of cold brew

Japan has a well-established tradition of slow-drip cold coffee, known as Kyoto-style after the city most associated with it. You’ll often read that it dates back to the 1600s and arrived with Dutch traders, but I couldn’t find any documented evidence for that, so treat it as legend rather than history.

In 1964, according to Toddy’s own guide, its felt-filter cold brew method was developed; retailers credit Todd Simpson, a chemical engineering graduate of Cornell University, with developing and patenting the Toddy system. It’s still sold today.

Cold brew went mainstream in the 2010s, as specialty cafés and then big coffee chains put it on their menus. Nitro cold brew followed, though its exact origin is disputed. Cuvée Coffee in Austin, Texas is usually credited with first serving it on tap in 2012, and Wikipedia notes it may have originated at Cuvée and Stumptown Coffee Roasters in Portland around 2013.

Cold brew vs other methods

• Japanese iced coffee: brewed hot onto ice in minutes; brighter and more aromatic, best drunk straight away.
• French press: the same steeping idea in hot water, done in four minutes; fuller and more intense.
• V60: hot pour-over for a clean, bright cup; brew it onto ice for an iced version.
• Vietnamese iced coffee: strong coffee from a phin filter over ice with condensed milk; sweeter and bolder.
• Greek frappé: instant coffee shaken into a foam over ice; quick, frothy and very different.

Explore every chilled and slow-steeped coffee in the cold coffee chapter.