How to make cold brew coffee at home

Learning how to make cold brew coffee takes about five minutes of work and a day of patience. Instead of hot water, you steep coarsely ground coffee in cold or room-temperature water for many hours, then strain it. The result is smooth, rounded and low in bitterness, and it keeps in the fridge so you can pour a glass whenever you want.

This guide covers the equipment, the coffee-to-water ratio, grind size, steeping time, filtering, dilution and storage, with notes on keeping it safe.

What is cold brew coffee?

Cold brew is coffee made by steeping grounds in cold or room-temperature water, typically for 12 to 24 hours, rather than brewing with hot water for a few minutes. Because the water is cool, it extracts flavour slowly and pulls out fewer of the compounds that taste sharp and bitter.

Cold brew is not the same as iced coffee. Iced coffee is hot-brewed coffee that is cooled or poured over ice, which keeps more bright, fruity acidity. A related style, slow-drip or Kyoto-style coffee, drips cold water through a bed of grounds over several hours using a tower brewer.

What you need

You do not need special equipment. A large jar and a way to filter are enough, although a French press makes the job tidier.

• Whole coffee beans, ideally medium or dark roast for a classic chocolatey cold brew.
• A grinder that can produce a coarse grind.
• Cold, filtered water.
• A large jar, jug or French press.
• A filter: a fine sieve plus a paper coffee filter, a cloth or a nut milk bag.
• A clean bottle with a lid for storing the finished coffee.

Cold brew trades heat for time, and the reward is a smoother cup.

The cold brew coffee ratio

Most home recipes land between 1:4 and 1:8 coffee to water by weight. A stronger ratio, around 1:4 to 1:5, gives a concentrate you dilute before drinking. A weaker ratio, around 1:8, can be drunk straight over ice.

A practical starting point is 100 g of coffee to 500 g (500 ml) of water for concentrate, or 100 g to about 800 ml for ready-to-drink cold brew. Adjust from there: add more coffee if it tastes thin, more water or less time if it tastes heavy or muddy.

How to make cold brew coffee, step by step

Once you have your ratio, the process is simple.

• Grind the beans coarsely, roughly like raw sugar or coarse sea salt.
• Put the grounds in the jar or French press and pour over the cold water.
• Stir gently so all the grounds are wet, with no dry clumps.
• Cover the container and steep for 12 to 24 hours, ideally in the fridge.
• Strain through a sieve to remove most of the grounds, then filter again through paper or cloth for a clean result.
• Pour the finished coffee into a clean bottle, seal it and refrigerate.
• To serve, pour over ice and dilute concentrate with water or milk to taste.

How long should cold brew steep?

Steeping time and temperature work together. In the fridge, extraction is slower, so many people steep for 16 to 24 hours. At room temperature, 12 to 18 hours is common. Under-steeped cold brew tastes weak and watery; over-steeped cold brew can taste woody, dull or bitter.

Grind size matters too. Fine grounds extract too fast, taste muddy and clog filters. Coarse grounds give a cleaner cup and are much easier to strain.

Fridge or counter? Food safety notes for cold brew

Cold brew is never heated to boiling, and coffee is a low-acid drink, so hygiene and cold storage matter more than with hot coffee. Steeping in the fridge is the safest choice. If you steep at room temperature, keep it to the shorter end of the time range, in a clean covered container out of the sun, then refrigerate immediately after straining.

Keep finished cold brew in the fridge in a clean, sealed bottle. Undiluted concentrate generally keeps its flavour for about a week, and diluted cold brew or cold brew mixed with milk should be drunk within a day or two. Do not keep homemade cold brew sealed at room temperature for long periods. Throw it out if it smells sour or musty, looks cloudy in an unusual way or has anything growing on the surface.

Wash jars, filters and bottles thoroughly between batches, since old coffee oils and residue can harbour microbes and turn rancid.

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

Cold brew often tastes less acidic, and studies suggest it tends to have lower titratable acidity than hot coffee, although the pH of the two can be quite similar. Many people with sensitive stomachs still find it gentler, but it is not acid-free.

Caffeine depends on the recipe. Cold brew concentrate can be very strong because it uses a lot of coffee. Once diluted, a glass of cold brew may contain a similar amount of caffeine to a cup of hot filter coffee, or more, depending on your ratio and how much water you add. If you are watching your intake, measure your dilution.

Ways to serve cold brew

Cold brew is versatile. Drink it black over ice, add cold milk or a plant drink, or stir in a little simple syrup, since granulated sugar dissolves poorly in cold liquid. Freeze some cold brew in an ice-cube tray so your drink does not get watery as the ice melts.

Concentrate also works in cooking: add a splash to smoothies, overnight oats, tiramisu or chocolate desserts. For a warm drink, dilute concentrate with hot water; it will taste smoother than freshly brewed coffee.

Frequently asked questions

Once you know how to make cold brew coffee, it becomes an easy routine: grind coarse, stir, steep in the fridge overnight, filter and chill. Tune the ratio and steeping time to your taste, keep everything clean and cold, and you will have smooth coffee ready whenever you want it.

How we research: Guides are written from established sources and checked for accuracy. They are general information, not professional advice.