How to Make Cold Brew Concentrate
By Mia Hartwell
Cold brew concentrate is the most useful thing you can keep in a fridge door. One jar takes about ten minutes of actual work, sits quietly overnight, and then covers your coffee for the next two weeks. No grinding at seven in the morning, no waiting for a kettle, just pour and dilute. It is the closest thing to a coffee shop on retainer.
The word concentrate is where most people go wrong, though. A lot of recipes use it loosely for any cold steeped coffee, and if you brew a batch at a ready to drink ratio and then dilute it the way a concentrate recipe tells you to, you get something thin and disappointing. The difference between the two is entirely down to the ratio you start with, and once that clicks the whole thing becomes reliable.
This guide covers the ratio, the grind, the steep window, how to strain it so it comes out clean, how long it actually keeps, and exactly how much water or milk to add for each kind of drink. It is the batch method, so it is meant to be made once and used all week.
Concentrate vs Ready to Drink Cold Brew
Both are made the same way, by steeping coarse coffee in cold water for many hours. The only difference is how much water you use, and that single choice determines everything about how you store and serve it.
Concentrate is brewed at roughly 1 part coffee to 5 parts water. It comes out two to three times the strength of regular coffee, takes up much less fridge space, and keeps for around two weeks because there is less water in it to go stale. You cut it with water or milk in the glass.
Ready to drink cold brew is brewed at about 1 to 8. It needs no dilution and you pour it straight over ice, but it takes a whole pitcher of space and is best within a few days. If you drink cold brew every day and have the fridge room, it is simpler. If you want flexibility, make concentrate.
For a broader look at every method of making cold coffee, including the five minute flash brew for mornings you did not plan ahead, see our guide on how to make iced coffee.
What You Need
- Coffee beans, 1 cup. Medium or dark roast for classic chocolatey cold brew, light roast if you want something fruitier.
- Cold filtered water, 5 cups. Cold brew is mostly water, so if your tap water tastes of chlorine it will taste of chlorine for two weeks.
- A large jar or pitcher. Anything sealable that holds at least six cups.
- A fine mesh strainer. For the first pass.
- A paper filter or cheesecloth. For the second pass, which is what makes it clean rather than silty.
- A sealable storage bottle. Glass is best, and a narrow neck limits how much air sits on top.
How to Make Cold Brew Concentrate
Total hands on time is about ten minutes, split across two sessions roughly a day apart.
Grind the coffee coarse
Grind 1 cup of beans to a coarse texture, similar to raw sugar or breadcrumbs. This is the step that decides whether the batch is smooth or muddy. Cold water pulls flavor slowly, so the long steep is doing the work that heat normally would, and fine grounds will over-extract badly over that many hours.
Combine at a 1 to 5 ratio
Put the grounds in your jar and pour over 5 cups of cold filtered water. Then stir properly. Dry grounds float and clump together, and any pocket that stays dry is coffee you paid for and did not use. Stir again after a few minutes once everything has settled.
Steep for 12 to 18 hours
Cover the jar and leave it on the counter for 12 to 18 hours, or in the fridge for 16 to 24 since cold slows extraction down. Twelve hours gives a brighter, lighter concentrate and eighteen gives a deeper, more chocolatey one. Do not push past 24 hours, where the flavor turns woody and papery.
Strain it twice
Pour the batch through a fine mesh strainer to catch the grounds, then run it through a paper filter or a double layer of cheesecloth to catch the fine sediment that gets past the first pass. The second strain is what separates clean concentrate from something with a gritty layer at the bottom. Do not press or squeeze the grounds, however tempting it is.
Bottle and refrigerate
Pour into a clean sealed bottle and put it in the fridge. Undiluted, it holds up well for about two weeks. Label it with the date if you are the sort of person who will otherwise find a mystery bottle of something dark in three weeks time.
Dilute as you pour
Never dilute the whole batch. Mix each glass individually so the stored concentrate keeps its two week life. One part concentrate to one part water or milk over ice is the standard starting point, then adjust from there.
Ratios: Which Strength to Brew
| Style | Ratio | Example | How to Use |
|---|---|---|---|
| Strong concentrate | 1:4 | 1 cup coffee to 4 cups water | Dilute 1:1 or more, most intense |
| Standard concentrate | 1:5 | 1 cup coffee to 5 cups water | The reliable default, dilute 1:1 |
| Light concentrate | 1:6 | 1 cup coffee to 6 cups water | Dilute lightly, milder result |
| Ready to drink | 1:8 | 1 cup coffee to 8 cups water | No dilution, pour straight over ice |
How to Dilute It
These are starting points rather than rules. Taste the first glass and adjust, since roast and grind both shift the strength a little.
| Drink | Mix | Notes |
|---|---|---|
| Iced coffee | 1 part concentrate to 1 part water | Over a full glass of ice |
| Iced latte | 1 part concentrate to 1 part milk | Oat or whole milk works best |
| Hot coffee | 1 part concentrate to 2 parts hot water | Heat gently, do not boil |
| Cold brew americano | 1 part concentrate to 3 parts water | Lighter and more sessionable |
One thing worth knowing for iced drinks: ice melts and dilutes further as you drink, so use slightly less water in an iced glass than you would in a hot cup. Freezing some of the concentrate into ice cubes solves this permanently, since the cubes then add coffee rather than water as they melt.
Ways to Use It
- Iced latte. Equal parts concentrate and cold milk over a full glass of ice.
- Hot cold brew. One part concentrate to two parts hot water. Smoother and less acidic than a normal hot cup, and genuinely good in winter.
- Sweet cream cold brew. Stir a splash of cream and vanilla syrup into the milk before pouring.
- Dirty matcha. Pour a small measure of concentrate over a matcha latte for something layered and unusually good.
- Coffee ice cubes. Freeze leftover concentrate in a tray for iced drinks that never go watery.
Common Mistakes to Avoid
Cold brew is forgiving in most ways, but these are the mistakes that cost you a whole batch and eighteen hours of waiting.
Grinding the coffee too fine
This is the mistake that ruins whole batches. Cold water extracts slowly and gently, so cold brew relies on a very long contact time rather than a fine grind. Over 12 or more hours, fine particles expose far too much surface area and keep extracting well past the pleasant compounds into harsh, woody ones. They also slip through every filter, leaving a silty sludge in the bottom of the bottle.
Do this instead: Grind coarse, like raw sugar or breadcrumbs. If you buy pre-ground, ask specifically for a French press grind rather than standard drip.
Treating 1:8 as a concentrate
A lot of recipes label anything cold steeped as concentrate, but ratio determines whether it actually is one. Coffee brewed at 1:8 is roughly ready to drink as it comes, so diluting it another one to one gives you something closer to brown water. People then assume cold brew is inherently weak, when the real issue is that they diluted a finished drink.
Do this instead: Brew at 1:5 if you intend to dilute, or 1:8 if you want to pour it straight over ice. Decide which one you are making before you start.
Not stirring after adding the water
Dry coffee grounds float and clump, and any pocket that stays dry contributes nothing to the batch. You end up with a concentrate that is weaker than the ratio suggests and inconsistent from jar to jar, which makes dialing in your dilution impossible because the starting strength keeps changing.
Do this instead: Stir thoroughly right after pouring the water, making sure every ground is wet, then give it another stir a few minutes later once the coffee has settled.
Steeping far longer than 24 hours
The assumption that more time means more strength only holds for a while. Once the sugars, oils, and pleasant acids have been extracted, the water keeps working on the woody cellulose of the grounds. The concentrate does not get stronger in any useful sense, it gets flat, dusty, and papery, and no amount of dilution will hide it.
Do this instead: Stay within 12 to 18 hours at room temperature or 16 to 24 in the fridge, then strain immediately. Set an alarm if you are brewing overnight.
Leaving the grounds in the finished batch
Straining is not a formality you can postpone. As long as the grounds are sitting in the liquid, extraction continues even in the fridge, so a batch you meant to stop at 16 hours quietly becomes a 40 hour batch. The concentrate you tasted and liked on day one will not be the same drink by day three.
Do this instead: Strain the entire batch as soon as the steep time is up, even if you are not going to drink any yet. Store it clean and grounds free.
Squeezing the filter to get more out
The liquid still clinging to spent grounds is not the same as what drained freely. It carries the fine sediment and the concentrated bitter compounds that the gentle cold steep specifically avoided. Wringing out a cheesecloth to rescue the last half cup undoes the smoothness that made the eighteen hour wait worthwhile.
Do this instead: Let it drain under gravity and accept a slightly lower yield. If you want more volume, start with a larger batch rather than pressing the grounds.
Diluting the whole batch at once
It seems convenient to make it drink ready, but diluted cold brew has the shelf life of ordinary brewed coffee, which is two or three days before it goes stale and flat. Undiluted concentrate lasts two weeks. Diluting up front throws away the single biggest advantage of making concentrate in the first place.
Do this instead: Store it undiluted in a sealed bottle and mix each glass as you pour it. It also lets you make it stronger or weaker depending on the day.
Using stale beans because it is a big batch
Cold brew is often treated as the place to use up old coffee, on the logic that the long steep will extract something from anything. It will, but staleness comes through clearly, and you are committing a full cup of beans and eighteen hours to the result. A flat batch is a flat two weeks.
Do this instead: Use beans roasted within the last month. Medium and dark roasts give the classic chocolatey cold brew character, while light roasts come out surprisingly fruity.
Storage and Shelf Life
Keep the concentrate undiluted in a sealed bottle in the fridge and it will stay good for about two weeks, with the first week noticeably brighter than the second. Once diluted it is ordinary brewed coffee and should be drunk within two or three days. Glass is better than plastic, which picks up coffee oils over time, and a narrower bottle leaves less air sitting on the surface to oxidise it. If it ever smells sour rather than sweet and roasted, pour it out and start again.
The short version
One cup coarse ground coffee to five cups cold water. Stir well, cover, and steep 12 to 18 hours at room temperature. Strain through mesh, then through paper, without squeezing. Bottle it and keep it in the fridge for up to two weeks. Dilute one to one with water or milk in the glass, never in the bottle.
Make it once and the habit tends to stick. A jar started on Sunday evening covers the whole week, and the marginal cost of each glass is small enough to be funny compared to buying the same drink out.
If you want the other methods for cold coffee, including flash brew for when you have five minutes rather than eighteen hours, start with how to make iced coffee. The same cold steeping principle also works beautifully for tea, which our guide on how to make tea covers alongside hot brewing temperatures. You can browse everything else in our kitchen guides.
Frequently Asked Questions
What is the ratio for cold brew concentrate?+
Use 1 part coarse ground coffee to 5 parts cold water by volume, so 1 cup of grounds to 5 cups of water. That produces a true concentrate you dilute roughly one to one before drinking. If you prefer it stronger, go to 1:4. Ratios around 1:8 make cold brew that is ready to drink straight from the jar rather than a concentrate.
How long does cold brew concentrate last in the fridge?+
Undiluted concentrate keeps well in a sealed jar in the fridge for up to two weeks, which is the main practical reason to make it. Once you dilute it with water or milk it behaves like ordinary brewed coffee and is best within two or three days. Always store it undiluted and mix each glass as you go.
How do you dilute cold brew concentrate?+
Start at one part concentrate to one part water or milk, then adjust to taste. For iced coffee, fill a glass with ice, add equal parts concentrate and milk, and taste before adding more. For a hot cup, mix one part concentrate with two parts hot water. Because ice melts and dilutes further, use slightly less water in an iced drink than a hot one.
How long should cold brew concentrate steep?+
Steep 12 to 18 hours at room temperature, or 16 to 24 hours in the fridge since cold slows extraction. Twelve hours gives a brighter, lighter concentrate and eighteen gives something deeper and more chocolatey. Past about 24 hours the flavor turns woody and dull, so strain it as soon as the window closes rather than leaving the grounds in.
What grind should I use for cold brew concentrate?+
Coarse, roughly the texture of raw sugar or breadcrumbs. Cold water extracts slowly, so a long steep does the work that heat would normally do, and fine grounds over-extract and turn the batch harsh and muddy. Fine particles also clog the filter and make straining slow and messy. If you buy pre-ground, ask for a French press grind.
Can you drink cold brew concentrate straight?+
You can, but most people find it far too intense. At a 1:5 ratio the concentrate is roughly two to three times the strength of regular brewed coffee, so an undiluted cup carries a great deal of caffeine and a very heavy body. It is designed to be cut with water or milk. If you like drinking it neat, brew at 1:8 instead so it is ready as it is.