How to Make Cold Brew Coffee at Home
Cold brew is coffee steeped in cold water for 16-18 hours. No heat, no special equipment, no technique. A mason jar and coarse grounds. Here's how to make it, how to not mess up the ratio, and how long it actually lasts in the fridge.
Time to read
7 min
Sections
6 + FAQ
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What you need to make cold brew
The equipment list is short. That's the whole point.
A jar or pitcher. A quart-size mason jar works for a single batch. A 2-quart pitcher works for a week's supply. Any container that seals and fits in your fridge. Dedicated cold brew makers like the Takeya Deluxe are nice but not required. They're a convenience upgrade, not a necessity.
Coarse ground coffee. Same grind you'd use for French press. Rough sea salt texture. This is the one variable that matters most. Too fine and your cold brew will be bitter and impossible to strain cleanly. Too coarse and it'll taste weak and sour.
Cold filtered water. Filtered matters here more than with hot coffee. You're soaking grounds for 16+ hours. Chlorine and mineral off-flavors in tap water have all that time to make themselves known. A basic pitcher filter is enough.
A fine mesh strainer and cheesecloth. For straining after steeping. The mesh catches the bulk of the grounds. The cheesecloth catches the fines. You can also use a paper coffee filter inside the strainer, but it drains slowly.
Optional: a kitchen scale. Makes the ratio precise. Not required. Cup measures work fine for cold brew.
The basic method: mason jar cold brew
No dedicated equipment needed. Six steps, 2 minutes of active work, then the fridge does the rest.
Grind your coffee coarse
Grind to a coarse setting — the grounds should look like rough sea salt. If you're buying pre-ground, look for "coarse grind" on the bag. Standard drip grind will work but makes straining harder and leans bitter. If you own a burr grinder, set it to the French press range.
Combine coffee and water
For ready-to-drink cold brew, use a 1:8 ratio by weight. That's 60 grams of coffee to 480 grams (about 2 cups) of cold filtered water. For concentrate (you'll dilute it later), use a 1:5 ratio — 100 grams of coffee to 500 grams of water. In cup terms: 1 cup of coarse grounds to 4 cups of water makes concentrate. 1 cup to 8 cups makes ready-to-drink.
Stir once to saturate
Give it a gentle stir to make sure all the grounds are wet. Dry pockets of grounds won't extract. One slow stir is plenty. Don't agitate it like you're making a smoothie.
Cover and refrigerate for 16-18 hours
Seal the jar and put it in the fridge. Set a timer or a reminder. 16-18 hours is the sweet spot — long enough for full extraction, short enough to avoid bitterness. 12 hours works in a pinch but tastes thinner. Going past 24 hours risks over-extraction and harsh, woody flavors.
Strain through mesh and cheesecloth
Set a fine mesh strainer over a clean jar or pitcher. Line it with cheesecloth or a paper filter. Pour the cold brew through slowly. Let gravity do the work. Do not squeeze the cheesecloth. Squeezing forces bitter compounds and fine sediment through, ruining the smooth texture you just spent 18 hours building.
Serve or store
If you made ready-to-drink (1:8), pour it straight over ice. If you made concentrate (1:5), dilute it 1:1 with cold water, milk, or pour it over a full glass of ice. Concentrate is versatile — it's the base for iced lattes, coffee cocktails, and anything else where you need a strong coffee hit without heat.
Cold brew coffee ratio: the one thing people get wrong
The cold brew coffee ratio is the single biggest variable. Get it wrong and everything else — grind, steep time, beans — won't save you.
Ready-to-drink: 1:8 by weight. 60g coffee to 480g water. This makes a smooth, balanced cold brew you pour straight over ice without diluting. Most people should start here.
Concentrate: 1:5 by weight. 100g coffee to 500g water. This makes a strong, intense liquid that you dilute before drinking. It's how coffee shops do it. Concentrate is more flexible and stores longer, but you have to dilute it or it'll taste overwhelming.
Diluting concentrate: Mix 1 part concentrate with 1 part cold water for standard strength. Use 1 part concentrate to 2 parts water for lighter cold brew. Mix with milk instead of water for an instant iced latte. Pour over a full glass of ice and let the melt do the diluting.
Weight vs volume: A kitchen scale is more accurate than measuring cups because coffee density varies by roast and grind. But for cold brew, cup measures work fine. The margin of error is small enough that it doesn't ruin the batch. If you're using cups: 1 cup grounds to 4 cups water for concentrate. 1 cup grounds to 8 cups water for ready-to-drink.
Adjusting strength after brewing: If the final result is too strong, add water or ice. If it's too weak, the ratio was off. You can't fix a weak batch by steeping it longer next time — that changes the flavor profile, not just the strength. Adjust the ratio instead.
Concentrate vs ready-to-drink: which to make
They're not the same thing. Most cold brew confusion starts here.
Concentrate is a strong extraction that you dilute before drinking. It's roughly 2x the strength of regular coffee. On its own it tastes intense, almost syrupy. It's not meant to be sipped straight.
Ready-to-drink is a weaker extraction brewed at the right strength from the start. No dilution needed. Pour over ice and go.
When to make concentrate: You batch-prep for the week. Concentrate lasts 10-14 days in the fridge — nearly twice as long as ready-to-drink. One batch covers Monday through Sunday. You want versatility. Concentrate is the base for iced lattes (mix with milk), coffee cocktails (espresso martinis, white Russians), baking (brownies, tiramisu), or just a quick glass over ice. You share with people who like different strengths. Everyone dilutes to their own preference.
When to make ready-to-drink: You drink it yourself and want zero prep in the morning. Grab the jar, pour over ice, done. You know exactly how you like your cold brew and don't want to think about dilution ratios.
The practical answer: If you're making cold brew for the first time, start with ready-to-drink at 1:8. It's simpler, tastes good immediately, and you'll learn whether you want it stronger or weaker before committing to concentrate batches.
Troubleshooting: bitter, sour, or weak cold brew
Your cold brew doesn't taste right. Here's how to diagnose it.
Bitter cold brew. The most common problem. Caused by over-extraction — the water pulled too much from the grounds. Three likely culprits: your grind is too fine (more surface area = faster extraction), you steeped it too long (anything past 24 hours gets harsh), or you squeezed the cheesecloth while straining (forces bitter compounds through). Fix: grind coarser, steep 16-18 hours instead of 24, and let gravity strain it.
Sour cold brew. The opposite problem — under-extraction. The water didn't pull enough flavor. Causes: grind is too coarse (not enough surface area), or steep time was too short (under 12 hours). Fix: grind slightly finer (still coarse, just less so) and steep the full 16-18 hours.
Weak, watery cold brew. Almost always a ratio problem. You used too little coffee. Fix: use more. Go from 1:8 to 1:7 or even 1:6. If the ratio is right but it still tastes thin, your grind might be too coarse — the water is passing through without extracting enough.
Cloudy or gritty cold brew. Straining problem. The mesh wasn't fine enough, or you squeezed the filter. Fix: double-strain through cheesecloth or use a paper coffee filter for the second pass. The Toddy cold brew system uses a felt filter that solves this completely.
Stale or flat tasting. Your batch is past its prime. Cold brew flavor peaks in the first 3-5 days. After 7 days it tastes dull even if it's technically safe to drink. Make smaller batches more often.
The one-variable rule applies here too. Change grind first. Then ratio. Then steep time. One at a time. If you change everything at once, you won't know what fixed it.
How long cold brew lasts and how to store it
Cold brew lasts longer than hot-brewed coffee, but not as long as people think.
Undiluted cold brew: 7 days in the fridge in an airtight container. Flavor is best for the first 3-5 days. After day 5, oxidation dulls the taste. It's still safe to drink through day 7 but it won't taste as good as it did on day 2.
Concentrate: 10-14 days in the fridge. The higher coffee-to-water ratio preserves it longer. This is the main practical advantage of making concentrate — one batch lasts almost two weeks.
Diluted cold brew (with water or milk): 2-3 days. Once you add water or dairy, the shelf life drops dramatically. The dairy starts turning, and the diluted coffee oxidizes faster. Don't pre-dilute a whole batch. Dilute each glass as you pour it.
Storage rules: Use glass containers with airtight lids. Mason jars with screw-top lids work perfectly. Glass doesn't absorb flavors the way plastic does. Keep it in the fridge at 40F or below. Room temperature storage is not safe for more than a few hours — bacteria love room-temp coffee. Don't store it in the door of the fridge. The door temperature fluctuates every time you open it. Back of a shelf is better.
Signs it's gone bad: Sour smell (not the good fruity kind — the spoiled kind), visible mold, or a noticeably bitter/off taste that wasn't there when you made it. When in doubt, dump it. A new batch takes 2 minutes of active work.
FAQ
1How long should cold brew steep?
16-18 hours in the refrigerator is the sweet spot. 12 hours works but the flavor is thinner. Going past 24 hours risks over-extraction — the cold brew starts tasting bitter and woody. Set a timer when you put it in the fridge. Most people make it before bed and strain it when they wake up the next morning.
2What grind size for cold brew?
Coarse, like rough sea salt. The same grind you'd use for a French press. On most burr grinders that's the coarsest setting or one step finer. Too fine and the cold brew will be bitter, muddy, and hard to strain. Too coarse and it'll taste weak and sour. If you're buying pre-ground, look for bags labeled 'coarse grind' — standard drip grind works but leans more bitter.
3What is the difference between cold brew and iced coffee?
Cold brew steeps grounds in cold water for 12-24 hours. Iced coffee brews hot and pours over ice. They taste different: cold brew is smoother, sweeter, and about 67% less acidic. Iced coffee keeps the brighter acidity of hot-brewed coffee but dilutes as the ice melts. Cold brew also has more caffeine — roughly 200-280mg per 16oz compared to about 165mg for iced coffee the same size.
4Can I use pre-ground coffee for cold brew?
Yes, but most pre-ground coffee is a medium grind designed for drip machines. It works for cold brew — the result will lean slightly more bitter and be harder to strain cleanly. If you can find pre-ground labeled 'coarse grind,' the results are much better. Grinding fresh from whole beans always produces the best cold brew because the flavor compounds haven't had time to oxidize.
5How long does cold brew last in the fridge?
Undiluted cold brew lasts about 7 days in an airtight container. Concentrate lasts 10-14 days. Once you add water or milk, the shelf life drops to 2-3 days. Flavor is best in the first 3-5 days for all types. Store in glass with an airtight lid, in the back of the fridge (not the door). If it smells sour or off, dump it.
6Do I need a cold brew maker?
No. A mason jar and a fine mesh strainer is all you need. Dedicated cold brew makers like the Takeya Deluxe or Toddy system are convenient for repeat batches — they have built-in filters that make straining easier and produce a cleaner result. But the coffee itself tastes the same either way. Start with a mason jar. If you find yourself making cold brew every week, the upgrade is worth it.
Ready to pick your gear?
Now that you know the technique, find the right equipment for your budget and goals.