Cold brew is one of the most forgiving coffee brewing methods available. It requires no special equipment, no precise temperature control, and no timing beyond leaving it in the refrigerator overnight. The result is a smooth, low-acid concentrate that keeps for up to two weeks and can be served in multiple ways.
The basic method is simple: combine coarsely ground coffee with cold water, let it steep for 12 to 24 hours, then strain out the grounds. What you are left with is cold brew concentrate, which you can dilute to taste or drink straight.
What You Need
The equipment list is minimal. You need a container large enough to hold your coffee and water — a mason jar, a large pitcher, or any food-safe container with a lid will work. You need a way to strain the grounds: a fine-mesh strainer lined with a paper coffee filter, a cheesecloth, or a nut milk bag all work well. And you need coarsely ground coffee and cold water.
You do not need a dedicated cold brew maker, a French press, or any specialized equipment. The commercial cold brew makers sold at kitchen stores are convenient but not necessary. A mason jar and a paper filter produce results that are indistinguishable from what a $40 cold brew pitcher produces.
The Coffee-to-Water Ratio
The standard ratio for cold brew concentrate is 1:4 by weight — 1 gram of coffee for every 4 grams of water. In volume terms, this is roughly 1 cup of coarsely ground coffee to 4 cups of cold water. This produces a concentrate that is intended to be diluted 1:1 with water or milk before drinking.
If you prefer to brew ready-to-drink cold brew rather than concentrate, use a 1:8 ratio — 1 cup of coffee to 8 cups of water. The result is less intense and can be drunk straight over ice without dilution.
The concentrate approach is more practical for home use. It takes up less refrigerator space, keeps longer, and gives you flexibility in how you serve it.
The Method
Start with coarsely ground coffee. The grind should be similar to what you would use for a French press — noticeably coarser than drip coffee, with visible grit rather than fine powder. A coarse grind is important because cold brew steeps for a long time; a fine grind will over-extract and produce a bitter, muddy result.
Combine the coffee and cold water in your container. Stir briefly to make sure all the grounds are saturated. Cover the container and place it in the refrigerator.
Steep for 12 to 24 hours. Twelve hours produces a lighter, brighter result. Twenty-four hours produces a heavier, more intense concentrate. Most people find 16 to 18 hours to be the sweet spot — enough time to develop full body and sweetness without tipping into over-extraction.
Do not steep at room temperature unless you plan to drink it within a few hours. Room-temperature steeping accelerates extraction and increases the risk of bacterial growth. The refrigerator is the right environment.
After steeping, strain the coffee through a fine-mesh strainer lined with a paper coffee filter. This takes 10 to 15 minutes. Do not press or squeeze the grounds — let gravity do the work. Pressing the grounds forces bitter compounds through the filter.
Transfer the strained concentrate to a clean jar or bottle and refrigerate. It will keep for up to two weeks.
How to Serve It
The most common way to serve cold brew concentrate is diluted 1:1 with cold water over ice. This produces a smooth, full-bodied iced coffee with noticeably less acidity than iced hot coffee.
For a richer drink, dilute with whole milk or oat milk instead of water. Cold brew and oat milk is a particularly good combination — the natural sweetness of oat milk complements the chocolate and caramel notes that cold brew tends to produce.
For a stronger drink, reduce the dilution ratio. Some people drink cold brew concentrate straight over ice, which produces an intensely flavored cup that is not for everyone but has its advocates.
Cold brew concentrate also works well in coffee cocktails, coffee-flavored desserts, and as a base for homemade coffee ice cream.
Common Mistakes
The most common mistake is using too fine a grind. Fine-ground coffee over-extracts during the long steep and produces a bitter, astringent result. Use a coarse grind.
The second most common mistake is steeping at room temperature for too long. A few hours at room temperature is fine; overnight at room temperature is not. Use the refrigerator.
The third mistake is using low-quality or stale coffee. Cold brew's low-acid, smooth character can mask some flaws, but it cannot rescue genuinely bad coffee. Use beans that are reasonably fresh — roasted within the past month — and of reasonable quality.
| Variable | Recommendation |
|---|---|
| Grind size | Coarse (French press level) |
| Coffee-to-water ratio (concentrate) | 1:4 by weight |
| Coffee-to-water ratio (ready-to-drink) | 1:8 by weight |
| Steep time | 16–18 hours (12–24 range) |
| Steep temperature | Refrigerator (34–40°F) |
| Shelf life | Up to 2 weeks refrigerated |
| Serving dilution (from concentrate) | 1:1 with water or milk |
Choosing Your Equipment
The good news about cold brew is that you do not need specialized equipment. Any food-safe container large enough to hold your coffee and water will work. The most common options:
Mason jar (32 oz or 64 oz): The simplest and most accessible option. A 32-ounce jar holds enough for a small batch (1 cup grounds + 4 cups water). A 64-ounce jar is better for larger batches. Mason jars are easy to seal, easy to clean, and widely available.
Large pitcher with lid: Works well for larger batches. A standard 2-quart pitcher holds enough for a week's worth of cold brew concentrate.
French press: An underrated cold brew vessel. Add grounds and water, steep in the refrigerator, then press the plunger to separate grounds from liquid. No separate straining step required.
Dedicated cold brew makers: Products like the OXO Cold Brew Maker or Toddy system are convenient but not necessary. They typically include a built-in filter that simplifies straining. The results are comparable to a mason jar and paper filter.
The Grind
Grind size is the most important variable in cold brew quality. Use a coarse grind — similar to or slightly coarser than French press. In terms of grinder settings, this is typically the coarsest 20–30% of the grinder's range.
A coarse grind serves two purposes: it prevents over-extraction during the long steep (fine grounds over-extract and produce bitter cold brew) and it makes filtering significantly easier (fine grounds clog paper filters and produce slow, frustrating straining).
If you do not have a burr grinder, most grocery stores and coffee shops will grind beans to order. Ask for a "coarse grind for cold brew" or "coarse grind for French press."
Step-by-Step: Making Cold Brew Concentrate
Ingredients: 1 cup (approximately 85g) coarsely ground coffee, 4 cups (950ml) cold or room-temperature water.
Equipment: 32-oz mason jar or pitcher, fine mesh strainer, paper coffee filter or cheesecloth.
- Add the ground coffee to your jar or pitcher.
- Pour the cold water over the grounds. Stir gently to ensure all grounds are saturated — dry pockets of coffee will not extract.
- Cover the container with a lid or plastic wrap.
- Place in the refrigerator and steep for 16–24 hours. Most recipes recommend 18–20 hours as a reliable default.
- Set a fine mesh strainer over a clean jar or pitcher. Line the strainer with a paper coffee filter.
- Pour the cold brew through the filter slowly. Allow it to drain completely — this may take 5–10 minutes.
- Discard the spent grounds. Transfer the strained concentrate to a sealed container.
- Refrigerate and use within 10–14 days.
Troubleshooting Common Problems
| Problem | Likely Cause | Fix |
|---|---|---|
| Bitter cold brew | Grind too fine, or steeped too long | Use coarser grind; reduce steep time to 16–18 hours |
| Weak, watery cold brew | Grind too coarse, ratio too dilute, or steeped too short | Use more coffee or increase steep time |
| Muddy, cloudy cold brew | Grind too fine; insufficient filtering | Use coarser grind; strain twice through paper filter |
| Slow filtering | Grind too fine | Use coarser grind; let filter drain without pressing |
| Flat, stale flavor | Beans too old | Use beans within 4 weeks of roast date |
Serving Suggestions
Classic: Dilute concentrate 1:1 with cold water over ice.
Latte-style: Dilute 1:1 with whole milk, oat milk, or your preferred milk alternative.
Sweetened: Add simple syrup, vanilla syrup, or flavored syrup to taste after diluting. Cold brew's low acidity pairs particularly well with vanilla and caramel.
Sparkling: Dilute 1:2 with sparkling water for a coffee soda.
Black, undiluted: A small amount (1–2 oz) of undiluted concentrate as a coffee shot is an intense, espresso-like experience. Not recommended in large quantities due to the high caffeine content.
Scaling the Recipe
The 1:4 ratio scales linearly. For a larger batch:
| Coffee | Water | Yield (approximate) |
|---|---|---|
| 1 cup (85g) | 4 cups (950ml) | ~3 cups concentrate |
| 2 cups (170g) | 8 cups (1.9L) | ~6 cups concentrate |
| 3 cups (255g) | 12 cups (2.8L) | ~9 cups concentrate |
A 3-cup batch of grounds produces enough concentrate for approximately 18 servings at a 1:1 dilution ratio — roughly a week's supply for a daily cold brew drinker.
For ratio reference and calculator, see the Cold Brew Ratio Guide.