How to Make Cold Brew Coffee at Home: The Complete Guide

Cold brew coffee is the smoothest, least acidic way to get your caffeine fix — and making it at home costs a fraction of what you'd pay at a café. Once you nail the ratio and timing, you'll never go back to buying $7 bottles at the grocery store.

Key Takeaways

The standard ratio is 1:8 (coffee to water by weight) for a concentrate; 1:15 for ready-to-drink

Use a coarse grind — roughly the texture of raw sugar

Steep for 12–18 hours in the fridge (never more than 24)

Any mason jar works; a dedicated cold brew maker makes straining far cleaner

Cold brew concentrate keeps in the fridge for up to 2 weeks

What Is Cold Brew Coffee (and Why Is It Different)?

Cold brew coffee is made by steeping coarsely ground coffee in cold or room-temperature water for 12 to 18 hours. Unlike hot-brewed coffee, no heat is used — which changes everything about the extraction process.

The result is a naturally sweeter, less acidic cup with roughly 65% less acidity than drip coffee. If you've ever had a bitter iced coffee and found it harsh on your stomach, cold brew coffee is the fix. The lower acidity makes it gentler for acid-sensitive drinkers without sacrificing caffeine or depth.

The Cold Brew Ratio: Getting It Right

The most common mistake people make is using the wrong coffee-to-water ratio. There are two main approaches:

Cold Brew Concentrate (Our Recommendation)

Ratio: 1:4 to 1:5 coffee to water by weight

Use 100g of coarsely ground coffee per 400–500ml of cold water
Steep for 12–16 hours
Dilute 1:1 with water, milk, or oat milk when serving

This is the most flexible method. You control strength daily by adjusting the dilution ratio.

Ready-to-Drink Cold Brew

Ratio: 1:12 to 1:15 coffee to water by weight

Use 65g of coffee per 1 liter of water
Steep for 14–18 hours
Serve directly over ice without diluting

This works best when you want grab-and-go convenience — pour into a glass of ice and go.

Why Grind Size Matters

Use a coarse grind — similar in texture to raw sugar or coarse sea salt. Finer grinds extract too quickly and produce a muddy, bitter concentrate. If you only have pre-ground coffee, choose a brand labeled "coarse" or "French press" grind.

For the best results, grind fresh before brewing. The OXO Brew Conical Burr Grinder ($100) has 38 grind settings and makes consistent coarse grinds that dramatically improve cold brew quality. It's the best burr grinder under $150 we've tested.

Step-by-Step: Making Cold Brew at Home

Cold brew requires almost no equipment and about 5 minutes of active prep time.

What you need:

Coarsely ground coffee (any roast; medium or dark roast is most popular)
Filtered cold water
A jar, pitcher, or dedicated cold brew maker
A fine mesh strainer, cheesecloth, or paper coffee filter

Instructions:

Measure your coffee. For a 32 oz batch (concentrate ratio): weigh out 100g (roughly ¾ cup) of coarse ground coffee.
Add coffee to your container. A quart-sized mason jar works perfectly for small batches. For a larger batch, use a half-gallon pitcher.
Add cold filtered water. Pour 400–500ml of cold water over the grounds. Stir gently until all grounds are saturated.
Cover and refrigerate. Cover loosely and place in the fridge. Avoid leaving it at room temperature longer than 2 hours — cold steeping is cleaner and safer.
Steep for 12–18 hours. Twelve hours gives a lighter, slightly floral cup. Sixteen to 18 hours produces a rich, intense concentrate. Don't go past 24 hours — over-steeped cold brew turns bitter and harsh.
Strain the coffee. Pour through a fine mesh strainer into a clean jar. For the clearest concentrate, strain a second time through a paper coffee filter. This takes 10–15 minutes but removes all sediment.
Dilute and serve. Mix equal parts concentrate and water, milk, or oat milk. Pour over ice.

Pro Tips That Make a Real Difference

Use filtered water. Chlorine and heavy minerals in tap water noticeably dull the flavor. Filtered or bottled water produces a cleaner, sweeter cup.

Start with freshly roasted beans. Cold brew amplifies coffee quality. Grocery-store coffee works, but beans roasted within 2–6 weeks produce a brighter, more nuanced concentrate.

Don't stir during steeping. Let the grounds settle and rest undisturbed. Stirring mid-steep can disrupt extraction and introduce bitterness.

Label your batch with the date. Concentrate stays fresh for up to 2 weeks in the fridge. Ready-to-drink cold brew keeps for 7–10 days. After that, the flavor flattens.

Experiment with roasts. Light roast gives a fruity, tea-like cold brew. Medium roast is balanced and sweet. Dark roast makes an intense, chocolatey concentrate — perfect for cold brew lattes with oat milk.

Equipment Worth Buying (and What to Skip)

The Best Cold Brew Makers

The OXO Good Grips Cold Brew Coffee Maker ($50) is our top pick for convenience. The built-in rainmaker lid evenly saturates grounds, and the bottom-tap design lets you dispense concentrate directly into a glass without pouring or mess. Cleanup takes under two minutes.

The Toddy Cold Brew System ($35) is the classic professional choice — a simple bucket and felt filter that produces a crystal-clear concentrate with zero sediment. It makes a larger batch than the OXO and is the system many coffee shops use.

For budget brewing, a 32oz mason jar and a paper coffee filter work just as well. The gear doesn't need to be expensive — the ratio and timing matter far more.

What to Skip

Cold brew pods, single-serve cold brew kits, and anything claiming to make "instant cold brew" in 20 minutes. Real cold brew takes time. Shortcuts produce a diluted, oxidized cup that's not worth the money.

Frequently Asked Questions

How long does cold brew last in the fridge? Cold brew concentrate lasts up to 2 weeks in an airtight container in the fridge. Ready-to-drink cold brew (already diluted) keeps for 7–10 days. It won't spoil dramatically, but the flavor flattens noticeably after those windows.

Can I use regular pre-ground coffee for cold brew? Yes, but a coarse grind makes a meaningfully better cup. If using pre-ground, choose a "French press" grind if available, and expect slightly more sediment to strain out.

Is cold brew stronger than regular coffee? Cold brew concentrate is roughly 2–3× the caffeine concentration of drip coffee before dilution. When diluted 1:1 with water or milk, the final cup has similar caffeine to a strong cup of drip coffee.

What coffee roast works best? Medium roast is the most forgiving and crowd-pleasing — balanced, sweet, and chocolatey. Dark roast makes a bold, rich concentrate ideal for lattes. Light roast gives a bright, fruity cup that's excellent but less forgiving of over-steeping.

Do I need a special cold brew maker? No. A mason jar and fine mesh strainer make excellent cold brew. A dedicated maker like the OXO just makes straining cleaner and more convenient — it doesn't change the coffee quality.