Cold Brew Recipe: Ratios, Steep Time and the Beans That Work Best

Here's the method we actually use, why it works, and where you have real room to adjust.

The Recipe

This makes a concentrate, meant to be diluted before drinking. It's the version that scales cleanly and keeps well in the fridge.

 

1. Coarsely grind 100g of coffee, roughly the texture of raw sugar or coarse sea salt.
2. Combine with 500g of room-temperature or cold filtered water in a large jar or pitcher (a 1:5 ratio).
3. Stir gently to make sure all the grounds are saturated, then cover.
4. Steep at room temperature for 14 to 16 hours, or in the fridge for 18 to 24 hours if your kitchen runs warm.
5. Strain through a fine mesh filter or a paper filter set over a funnel. Expect some sediment on the first pass; a second strain through a paper filter cleans it up.
6. Store the concentrate in a sealed glass container in the fridge for up to two weeks.
7. To serve, dilute 1:1 with water or milk over ice. Adjust to taste from there.

 

That 1:5 ratio sits deliberately stronger than most published recipes, which tend to cluster around 1:8 to 1:10. We'd rather hand you a concentrate you dilute to taste than a ready-to-drink brew that's already decided your strength for you.

Why Cold Brew Needs More Coffee, Not More Time

The instinct with cold brew is to compensate for the lack of heat by steeping longer, and to a point that's correct. But extraction in coffee is driven heavily by temperature, and cold water is simply a slower solvent no matter how long you wait.

Photo by Demi DeHerrera on Unsplash

 

Hot water molecules carry more kinetic energy, so extraction rate rises with brewing temperature and falls with a coarser grind, according to a 2023 study on immersion brewing published in Applied Food Research. The same research found that coffee-to-water ratio mainly changed extraction yield and acidity rather than how fast extraction happened, which is a useful distinction: ratio decides how much ends up in the cup, while temperature and grind decide how quickly it gets there.

In practice, this means dropping the ratio, not stretching the clock, is the more reliable lever. A 1:5 or 1:8 brew steeped 14 hours will consistently taste fuller than a 1:12 brew steeped 24 hours, because you've given cold water more coffee to work with instead of asking it to work harder than it's capable of.

Grind Size Is Not Optional Here

Every cold brew recipe says "coarse grind," and it's worth explaining why that instruction isn't negotiable the way it sometimes is for other methods. A fine or medium grind exposes far more surface area to the water, and over a 14-to-24-hour steep that translates into two problems: muddy sediment that makes it through even a careful strain, and an over-extracted, bitter cup that no amount of dilution fully fixes.

Grinding and contact time have the biggest effect on the finished brew's chemistry, according to a 2019 study out of Universidad de La Sabana in Colombia that tested cold brew across two grind levels and two steep times. Coarse grinding consistently produced higher total dissolved solids and extraction yield than medium grinding at the same steep time.

If you only have a blade grinder, cold brew is one of the few methods where inconsistency is genuinely forgiving, since the long steep smooths over some of the unevenness, but a burr grinder set coarse will still give you a cleaner result.

Steep Time: Longer Isn't Automatically Better

Here's the part that surprises people. The same Colombian study found that samples steeped for 22 hours scored higher on total dissolved solids, extraction yield, and phenolic content than those steeped for 14 hours, which sounds like a clear win for the longer steep.

But when a trained sensory panel actually tasted the results, the 14-hour, coarse-grind samples scored higher overall than the 22-hour batches, characterized by more sweetness and fruity, floral notes. The 22-hour brews measured "more extracted" without tasting better.

Photo by pariwat pannium on Unsplash

 

That's a useful distinction to hold onto: physicochemical measurements and how a cup actually tastes don't always move in the same direction. If your cold brew tastes flat after 24 hours, the fix isn't more time, it's more coffee relative to water, or accepting that somewhere between 12 and 16 hours is close to the ceiling of what actually improves flavor rather than just adding measurable strength.

Concentrate vs. Ready-to-Drink

These are two different products, and conflating them is where a lot of home cold brew goes wrong. A concentrate, brewed at a strong ratio like 1:4 or 1:5, is meant to be diluted before drinking, typically 1:1 with water or milk, sometimes 2:1 if you like it stronger.

A ready-to-drink cold brew is brewed at a lighter ratio, closer to 1:11 to 1:15, and served straight over ice with no dilution step.

The National Coffee Association's own brewing guidance sits closer to the concentrate camp, putting cold brew's coffee-to-water ratio at 1 gram of coffee to 4 to 5 grams of water, with roughly 12 hours of contact time at room temperature or cooler. Neither approach is more correct, but they're not interchangeable, and following a concentrate recipe as though it's ready to drink is the single most common reason people find cold brew "too strong" and swear off making it at home.

A few numbers worth keeping handy:

 

• Concentrate ratio: 1:4 to 1:5, diluted 1:1 to 2:1 before drinking
• Ready-to-drink ratio: 1:11 to 1:15, no dilution needed
• Typical steep time: 12 to 16 hours at room temperature, or up to 24 hours refrigerated
• Grind size: coarse, similar to coarse sea salt
• Fridge life once strained: up to 2 weeks for concentrate

 

The Beans Actually Matter More Than the Method

Cold brew's slow, gentle extraction pulls out sweetness and body more readily than the sharper acidity you'd get from a hot pour over, which is part of why medium and darker roasts have traditionally been the default choice.

But that's a preference, not a rule; a washed light roast with a naturally sweet profile can make an excellent cold brew, it'll just read differently than a chocolatey medium roast will. What actually matters more than roast level is freshness.

Photo by Amith Nair on Unsplash

 

Cold brew's long steep time means stale coffee has more time to show its flaws, not fewer, and a bag that's already lost its aromatics won't develop new ones just because it sat in water overnight.

We've written a full breakdown of which beans hold up best for cold brew at home, including which of our own roasts we'd reach for first. If you want to skip the trial and error, start with something from our current roast lineup roasted within the past few weeks, and treat the ratio and steep time above as your starting recipe rather than a rule you can't adjust.

Water quality matters here too, arguably more than in hot brewing. A 14-to-24-hour steep gives water plenty of time to pull flavor from whatever minerals or chlorine happen to be in it, alongside the coffee itself.

Filtered water produces a noticeably cleaner cold brew than straight tap water in most municipal systems, and it's a cheap fix if your cold brew has ever tasted slightly off in a way you couldn't pin on the beans or the ratio.

Cold Brew Isn't Just Iced Coffee

It's worth clearing up a mix-up that trips up a lot of first-time cold brewers: cold brew and iced coffee are not the same drink made two different ways. Iced coffee is regular hot-brewed coffee, made with heat, then cooled and poured over ice, sometimes brewed slightly stronger to account for dilution as the ice melts.

Cold brew never touches heat at any point; the entire extraction happens over hours at room temperature or in the fridge. That difference in process is also why the flavor profiles diverge so much. Iced coffee carries over the brighter acidity and sharper edges of hot extraction, just served cold, while cold brew's slow, low-temperature steep produces a naturally smoother, less acidic cup with more perceived sweetness, even using the exact same beans.

Common Cold Brew Mistakes Worth Avoiding

A few habits account for most of the disappointing homemade cold brew we hear about.

Using a fine or pre-ground drip coffee is the most common one. Pre-ground bags are almost always cut for drip machines, not immersion brewing, and that finer grind turns a 14-hour steep into a muddy, over-extracted mess. If your grocery store bag doesn't specify a grind size for cold brew, assume it's too fine and grind coarser yourself if you can.

Treating a concentrate recipe as ready to drink is the second. Straight, undiluted 1:5 concentrate is genuinely too strong and bitter for most people straight over ice, and the fix isn't a different recipe, it's the dilution step that concentrate recipes assume you'll make.

Steeping in direct sunlight or a warm spot is the third. Warmer ambient temperatures speed up extraction unevenly and can push a batch toward sour or off flavors well before the intended steep time is up. A dark cupboard or the fridge is more reliable than a sunny countertop, even at room temperature.

Finally, skipping the second strain. A single pass through a mesh strainer leaves fine sediment behind that continues to affect texture and can taste gritty by the time you finish the jar. A paper filter or coffee filter as a second pass, even a slow one, makes a noticeable difference in the final texture.

Scaling and Storing a Batch

The 100g-to-500g recipe above scales linearly, so doubling it for a full week's supply just means doubling both numbers. Keep the ratio fixed and only change the total volume based on how much of a jar or pitcher you have room for in the fridge.

Once strained, cold brew concentrate holds up well for about two weeks refrigerated in a sealed container, noticeably longer than brewed hot coffee, which starts to decline within hours. That shelf life is part of the appeal, since one batch on a Sunday can realistically cover a full week of drinking without a daily brewing routine.

Diluted, ready-to-drink cold brew doesn't keep quite as long once it's mixed with water or milk, so it's worth storing the concentrate undiluted and mixing individual servings as you go rather than diluting the entire batch at once.

Frequently Asked Questions

How long should I steep cold brew?

Between 12 and 16 hours at room temperature covers most recipes well, including the one above. Steeping longer, up to 24 hours, increases measurable strength but doesn't reliably improve flavor, and can push a brew toward flat or muddy rather than more balanced.

What's the best coffee-to-water ratio for cold brew?

For a concentrate meant to be diluted, use 1:4 to 1:5. For a ready-to-drink brew with no dilution step, use 1:11 to 1:15. These are genuinely different products, not two versions of the same ratio.

Can I use a fine grind for cold brew if that's all I have?

You can, but expect more sediment and a harsher, more bitter result over a long steep. If a fine grind is unavoidable, shorten the steep time toward the 12-hour end of the range to limit over-extraction.

Does cold brew have more caffeine than hot coffee?

It depends more on the ratio you use than the brewing method itself. A strong concentrate diluted lightly can end up more caffeinated per ounce than a standard drip cup, while a heavily diluted ready-to-drink cold brew often has less.

Start With the Ratio, Adjust From There

If your homemade cold brew has ever tasted watery or oddly flat, the fix is almost never a longer steep. Start at 1:5, coarse grind, 14 hours, and treat that as your baseline rather than a finished formula. From there, the only real variable worth touching first is how much you dilute it, not how long you wait.