How to Brew Cold Brew Coffee at Home Step by Step
Cold brew coffee is made without heat — a slow cold extraction over 16–24 hours produces a smooth, low-acid concentrate that keeps in the refrigerator for up to two weeks. The hands-on time is about five minutes. Everything else is patience.
Quick Answer
Combine 1 cup (100 g) coarsely ground coffee with 8 cups (1,900 ml) cold filtered water, stir to saturate, cover, and refrigerate for 16–24 hours. Strain through a fine-mesh sieve lined with a paper filter. Dilute the concentrate 1:1 with water or milk and serve over ice.
Cold Brew at a Glance
| Variable | Recommended Setting |
|---|---|
| Coffee-to-water ratio | 1:8 (concentrate) or 1:15 (ready-to-drink) |
| Grind size | Coarse — rough sea-salt texture |
| Water temperature | Cold or room temp, below 75°F (24°C) |
| Steep time | 16–24 hours in the refrigerator |
| Shelf life (concentrate) | Up to 2 weeks refrigerated in a sealed glass jar |
Step-by-Step: How to Make Cold Brew Coffee at Home
Step 1 — Choose Your Coffee and Grind Coarse
Use a coarse grind — the texture of rough sea salt or raw sugar. A coarse grind slows extraction and prevents the bitter, astringent compounds that a fine grind releases quickly in cold water. Medium-roast beans produce brighter, fruitier notes; dark-roast beans yield deeper chocolate and molasses flavors; light-roast beans give a delicate, tea-like sweetness that works especially well at the 1:15 ready-to-drink ratio. Any roast level works — choose based on your flavor preference.
Measure 1 cup (about 100 g) of coarsely ground coffee for a concentrate batch (8 cups water), or scale proportionally for larger volumes.
Step 2 — Combine Coffee and Cold Filtered Water
Add the ground coffee to a large glass jar, pitcher, or any container with a lid. Pour cold filtered water over the grounds — filtered water with moderate mineral content (around 150 ppm TDS) produces the cleanest, most balanced extraction. Stir gently with a long spoon until every ground is fully saturated, since dry pockets under-extract and create uneven, sour flavor. Cover the container with a lid or plastic wrap.
Step 3 — Steep in the Refrigerator for 16–24 Hours
Cold water extracts coffee slowly because lower temperatures reduce the solubility of flavor compounds. This is why steep time is measured in hours, not minutes — and why refrigerator steeping is the safest and most consistent method.
Place the covered container in the refrigerator and steep undisturbed. Sixteen hours produces a balanced, medium-strength concentrate; twenty to twenty-four hours yields a bolder, more intense result. Do not steep longer than 24 hours — beyond that point, cold extraction turns harsh and over-bitter even without heat.
Room-temperature steeping is faster (8–12 hours) but carries a meaningful food-safety risk past 12 hours: room temperature sits within the bacterial growth danger zone above 40°F (4°C). Refrigerator steeping eliminates this risk entirely and is the recommended method for home brewing.
Step 4 — Strain the Coffee Twice
Set a fine-mesh sieve over a clean pitcher or bowl and pour the steeped coffee through slowly. For a sediment-free, café-quality result, line the sieve with a paper coffee filter or two layers of cheesecloth and strain a second time. The second pass takes two extra minutes and produces a noticeably cleaner, smoother cup. Discard the spent grounds.
The strained liquid is your cold brew concentrate — dark, thick, and intensely flavored. That is exactly how it should look.
Step 5 — Serve and Store
To serve, combine the concentrate with an equal volume of cold water or milk (1:1 ratio) and pour over a glass filled with ice. Adjust dilution to taste — more water for a lighter cup, less for a stronger one. Cold brew concentrate served undiluted is roughly twice the caffeine strength of regular brewed coffee, so always dilute before drinking unless you specifically want a high-caffeine shot.
Store concentrate in a sealed glass jar or pitcher in the refrigerator. Cold brew concentrate keeps for up to 2 weeks when the coffee was fresh, the container is properly sealed, and the refrigerator holds below 40°F (4°C). Ready-to-drink cold brew (already diluted with water or milk) is best consumed within 5–7 days.
Common Mistakes When Brewing Cold Brew at Home
Using a grind that is too fine
Fine-ground coffee over-extracts quickly even in cold water, producing a bitter, gritty brew. Always use a coarse grind. If you are unsure, err on the coarser side — under-extraction (thin, slightly sour) is easier to correct by steeping longer than over-extraction (bitter) is to fix.
Steeping for fewer than 12 hours
Cold water extracts slowly. A 6- or 8-hour steep produces a thin, sour brew because the coffee has not had enough time to release its body and sweetness. Stick to 16–24 hours in the refrigerator for a balanced result.
Skipping the second strain
A single pass through a sieve often leaves fine sediment in the cup. A second pass through a paper filter takes two extra minutes and produces a noticeably cleaner, smoother drink. It is the single easiest upgrade to the basic method.
Steeping at room temperature for too long
Room-temperature cold brew left beyond 12 hours risks bacterial growth because room temperature exceeds 40°F (4°C) — the lower boundary of the food-safety danger zone. When in doubt, always use the refrigerator.
Drinking the concentrate straight
Cold brew concentrate is roughly twice the caffeine strength of regular brewed coffee. Serving it undiluted over ice is an easy way to accidentally overcaffeinate. Always dilute 1:1 before drinking unless you specifically want a high-caffeine shot.
Frequently Asked Questions
What is the best coffee-to-water ratio for cold brew?
The best cold brew ratio for a concentrate is 1:8 — 1 part coffee to 8 parts water by volume. For a ready-to-drink batch that needs no dilution, use 1:15. The 1:8 concentrate is more versatile because you can adjust strength at serving time by varying the dilution.
How long should cold brew steep in the refrigerator?
Cold brew steeps best for 16–24 hours in the refrigerator. Sixteen hours produces a balanced, medium-strength concentrate; twenty-four hours yields a bolder result. Steeping beyond 24 hours risks over-extraction and bitterness even with cold water.
Can I make cold brew without special equipment?
Yes — a large glass mason jar, a fine-mesh sieve, and a paper coffee filter are all you need. No dedicated cold brew maker or French press is required. That said, a cold brew pitcher with a built-in filter makes straining faster, produces a consistently cleaner cup, and eliminates the need for disposable paper filters over time. SERA's Home Cafe Essentials collection includes pitchers and strainers selected for exactly this use.
Why does my cold brew taste bitter?
Cold brew bitterness is almost always caused by one of three things: a grind that is too fine, a steep time over 24 hours, or water that is too warm during steeping. Use a coarse grind, keep steep time within 16–24 hours, and steep in the refrigerator to avoid bitterness.
How long does homemade cold brew last in the fridge?
Cold brew concentrate stored in a sealed glass container in the refrigerator stays fresh for up to 2 weeks, provided the coffee was fresh, the container seals properly, and the refrigerator holds below 40°F (4°C). Ready-to-drink cold brew is best consumed within 5–7 days.
Final Sip
Cold brew coffee is one of the most forgiving brews in a home café routine. The ratio is simple — 1:8 for concentrate. The grind is forgiving — just keep it coarse. The only real requirement is time: 16 to 24 hours in the refrigerator. Nail those three variables and you will have a smooth, low-acid concentrate ready every morning, made entirely on your own terms.
Quick Recap
- Ratio: 1:8 coffee-to-water for concentrate; 1:15 for ready-to-drink.
- Grind coarse — rough sea-salt texture prevents bitterness and sediment.
- Steep 16–24 hours in the refrigerator; 24 hours maximum.
- Strain twice — sieve first, then paper filter for a clean, sediment-free cup.
- Dilute concentrate 1:1 with water or milk before serving over ice.
- Store concentrate in a sealed glass jar; fresh for up to 2 weeks below 40°F (4°C).
Ready to brew? Get the right tools for the job.
SERA carries glass mason jars, fine-mesh strainers, cold brew pitchers, and coffee grinders selected for home café use — everything from this guide, in one place.