How to make cold brew coffee at home

To make cold brew, you stir coarsely ground coffee into cold water, leave it for many hours, then strain out the grounds. Sofía's recipe is 100 g of coarse coffee to 4 cups of cold water, steeped for 16 hours. It makes about 3 cups of strong, smooth coffee to pour over ice and dilute as you like.

What you need

• A jar or pitcher that holds at least 6 cups (1.5 liters), so there is room to stir.
• A fine mesh sieve, plus a paper coffee filter or a piece of cheesecloth.
• A grinder that can go coarse, and a kitchen scale.
• A bottle or jar with a lid for the finished coffee.

The recipe

1. Grind 100 g of coffee coarse, about like coarse sea salt or cracked pepper. A fine grind makes cold brew cloudy and bitter, and it clogs the filter so badly that straining takes forever.
2. Tip the grounds into the jar and pour in 4 cups of cold water. That is about 950 g. Filtered tap water is fine.
3. Stir until every ground is wet. Dry clumps float on top and never brew.
4. Cover the jar and leave it for 16 hours. Overnight plus a morning is about right.
5. Strain it through the sieve first, to catch most of the grounds. Then strain it again through a paper filter or cheesecloth, to catch the silt. Let it drip on its own. Squeezing the grounds pushes bitter sludge into the coffee.
6. Pour the finished cold brew into a clean bottle and put it in the fridge.

Where should the jar sit for those 16 hours? The recipe calls for cold water, and our suggestion is to steep it in the fridge, since that is where it ends up anyway and it stays cold from start to finish. Coffee extracts a little faster at room temperature, so if you steep on the counter, taste it at 12 hours and strain it when you like it.

A large French press makes a tidy half batch: 50 g of coffee and 2 cups of water, steeped the same way. Press slowly, then pour it through a paper filter.

Strength and diluting

This recipe works out to about one part coffee to nine and a half parts water, which is far more coffee than a hot cup uses. Cold water pulls flavor out slowly, so it needs the extra coffee and the long steep to taste full.

The result is strong. The grounds soak up some water, and you are left with about 3 cups of cold brew. Pour a glass over ice and taste it before you add anything, because melting ice dilutes it as you drink. If it is still too strong, add cold water or milk a splash at a time. Somewhere between a quarter as much and an equal amount of water suits most people.

Keep the jar undiluted and mix each glass as you pour it. Undiluted cold brew keeps better, and you can make every glass as strong as you want that day.

How long it keeps

Covered in the fridge, undiluted cold brew tastes its best for about a week. By two weeks it has usually turned flat and stale, even if it looks fine. Once you have added milk, drink it that day.

A 12 oz bag holds 340 g, enough for three full batches with a little left over.

Why cold brew tastes different from hot coffee

Heat pulls out acids and aromatic compounds quickly. Cold water gets some of them slowly and some of them barely at all. That is why cold brew tastes rounder and less bright than the same beans brewed hot.

A 2018 study in Scientific Reports by Niny Rao and Megan Fuller at Thomas Jefferson University measured this with light roasts, cold brewed for seven hours. The hot brewed coffee had more total titratable acids than cold brew made from the same beans, even though the pH of the two was close. Earlier studies the authors cite found that titratable acidity matches how sour a coffee tastes better than pH does, which fits what you notice in the glass: cold brew tastes mellow, and a hot cup tastes brighter.

If you love a coffee for its fruit and flowers, brew it hot onto ice instead. Our guide to iced pour over keeps those aromas that cold brew loses.

Which roast suits cold brew

Medium and dark roasts make the easiest cold brew. Their chocolate and caramel flavors come through well in cold water, and they do not lean on bright acidity the way light roasts do.

Our dark roast from Guatemala is the one we would pick. It comes from El Mirador in Huehuetenango, washed Bourbon and Caturra, with hints of toasted almond and brown sugar and a little orange at the end, and it takes milk well. Our medium roast from Colombia makes a slightly brighter cold brew with more fruit.

Light roasts can make a lovely, fruity cold brew too, but much of what makes them special needs hot water. For a light roast, grind a step finer than usual or let it steep a few hours longer if it tastes weak.