How to Brew Cold Brew Coffee at Home: Ratios, Timing, and Technique

Cold Brew Is the Easiest Coffee You Can Make

No kettle. No timer precision. No pouring technique. Cold brew coffee is grounds plus cold water plus time. That is it. The process is slow — 12 to 24 hours — but the hands-on effort is about two minutes.

The result is a smooth, low-acid, naturally sweet coffee that tastes completely different from any hot brewing method. Cold water extracts flavor compounds slowly and selectively, pulling out the sugars and chocolatey notes while leaving behind much of the bitterness and acidity. If hot-brewed coffee has been too harsh for your stomach, cold brew may solve that problem entirely.

Two Approaches: Concentrate vs Ready-to-Drink

Before you start, decide which you are making. They use different ratios and serve different purposes.

Cold Brew Concentrate (1:5 ratio)

Dose: 100g coffee | Water: 500g cold or room temperature | Steep: 16-20 hours

This produces a strong concentrate that you dilute before drinking, typically 1:1 with water, milk, or over ice. Concentrate is the better option if you want to batch brew for the week. It keeps in the refrigerator for 10-14 days and is versatile — use it straight over ice, dilute to taste, add milk, or mix into cocktails.

Ready-to-Drink (1:8 ratio)

Dose: 60g coffee | Water: 480g cold or room temperature | Steep: 12-16 hours

This produces cold brew at drinking strength — pour it over ice and you are done. No dilution needed. The flavor is lighter and more nuanced than concentrate. This is the better option if you want to drink it within a few days and prefer a cleaner, less intense cup.

Grind Size: Coarse to Extra Coarse

Grind coarse. Coarser than French press. Think raw sugar or even breadcrumb-sized particles.

Here is the truth about cold brew grinding: it is the least demanding method in all of coffee. Because the steep time is so long and the water is cold, the extraction process is gentle and slow. Fine particles over-extract into bitterness even in cold water given enough time, so coarser is safer. But cold brew is so forgiving that even moderately inconsistent grinds produce a good result.

On a Timemore C2, use the coarsest setting — 30+ clicks. On a Baratza Encore, setting 30-35. On a Comandante C40, 36-40 clicks.

Any burr grinder works for cold brew. You do not need a high-end grinder for this method. Even a Hario Skerton Pro or JavaPresse — grinders that struggle with pour-over consistency — perform perfectly fine for cold brew. If you are buying a grinder primarily for cold brew, do not overspend. Put that money into better beans instead.

The Method

1. Grind your coffee coarse. Weigh it.
2. Combine grounds and cold water in a jar, pitcher, or French press. Stir gently to make sure all grounds are saturated. No dry clumps.
3. Cover and let it sit for 12-24 hours. Room temperature or in the refrigerator — both work.
4. Strain through a fine mesh sieve, cheesecloth, paper filter, or French press plunger. If you want extra clarity, strain twice or filter through a paper coffee filter.

That is it. No special equipment required. A Mason jar and a fine mesh strainer handle the job.

Room Temperature vs Refrigerator

Room temperature extraction is faster and produces a slightly rounder, fuller flavor. Steep for 12-16 hours at room temp. Going past 20 hours risks over-extraction.

Refrigerator extraction is slower and produces a cleaner, brighter cup. Steep for 16-24 hours in the fridge. The cold slows extraction enough that over-steeping is harder to achieve.

Both approaches work well. Room temperature is more practical if you want results sooner. Refrigerator is more foolproof if you tend to forget about things. Either way, strain it as soon as your target time is reached.

Dilution and Serving

For concentrate (1:5 ratio), start with a 1:1 dilution — equal parts concentrate and water or milk. Taste it. Adjust from there. Some people prefer 1:1.5 or even 1:2 for a lighter drink. Over ice, start with less dilution since the ice melts and dilutes further.

For ready-to-drink (1:8 ratio), pour it straight over ice. No dilution needed. Add milk or sweetener to taste.

Cold brew concentrate makes an excellent base for iced lattes. Pour 100ml of concentrate over ice, top with milk. No espresso machine required.

Bean Selection

Cold brew favors medium to dark roasts. The low-acid extraction method pairs well with beans that have chocolate, caramel, and nutty notes. Brazilian, Colombian, and Sumatran origins tend to shine.

Light roasts can work but often taste flat and one-dimensional as cold brew. The bright, fruity, acidic notes that make light roasts interesting in hot pour-over are muted by cold extraction. If you love light roasts, a V60 or Chemex will showcase them far better.

The Bottom Line

Cold brew is the most forgiving brewing method in coffee. Coarse grind, cold water, 12-24 hours, strain. Use a 1:5 ratio for concentrate or 1:8 for ready-to-drink. Any grinder works. Any container works. The only thing you need is patience and decent beans.