Walk into any third-wave coffee shop in summer – Blue Bottle, Stumptown, Sightglass – and the cold brew is on tap behind the bar. The drink looks dark and ominous, like espresso but bigger. Tastes smooth, naturally sweet, low-acid, slightly chocolatey. Costs $6 in the cup. The recipe is just coffee and water plus 18 hours of patience. The whole thing can be made at home for about $1.50 per drink.
This is the 18-hour cold-brew concentrate method – coarse-ground coffee, room-temperature water, 18 hours of steeping, then double-filtered for clean concentrate. The result is 1 liter of strong coffee that dilutes 1:1 with water or milk and keeps refrigerated for 2 weeks. The technique is simple but the variables (grind size, time, temperature) matter more than people expect.
Quick Read — At a Glance
| Yield | 1 liter concentrate (8-10 servings diluted) |
| Total time | 18 hours 10 min (5 min prep + 18h steep) |
| Difficulty | Easy |
| Texture | Smooth, low-acid, slightly chocolatey |
| Critical | Coarse grind size – drip-grind makes muddy bitter concentrate |
Why Cold Brew Works
Hot water extracts coffee aggressively – acids, bitter compounds, oils, the works. Cold water extracts slowly and selectively – mostly the smooth, sweet, low-acid compounds. The result: cold brew is naturally less acidic (often 70% lower) and tastes sweeter without sugar.
The chemistry: high temperatures (85+ C) accelerate degradation of organic compounds, releasing chlorogenic acids and tannins that produce bitterness. Cold water (15-22 C) doesn’t cross those thresholds, so the coffee tastes smoother and less acidic.
Bean Selection
Medium-dark roast works best for cold brew. The roast develops chocolate, caramel, and nutty notes that come through beautifully in cold extraction. Light roasts produce thin, bright cold brew that lacks body. Darker espresso roasts work but lean toward bitterness.
Brand suggestions: Stumptown Hair Bender, Counter Culture Hologram, Intelligentsia Black Cat, Blue Bottle Bella Donovan. Supermarket options that work: Trader Joe’s Cold Brew Blend, Peet’s Major Dickason’s.
Ingredients
- 200 g (2 cups) coarse-ground coffee (medium-dark roast)
- 1 liter (4 1/4 cups) filtered water at room temperature
- Cheesecloth or paper coffee filter for straining
Making It
- Grind coarse. Sea salt texture. Burr grinder French press setting. NOT drip-grind.
- Combine. Coffee + water in large container or French press. Stir to wet all grounds.
- Steep 18h room temp. Cover. Do NOT refrigerate during steep.
- Strain mesh first. Fine-mesh strainer removes most grounds.
- Filter again. Cheesecloth or paper coffee filter for clean concentrate.
- Refrigerate. Keeps 2 weeks.
- Serve. 1:1 with water or milk over ice. Sweetener to taste.
Frequently Asked Questions
Cold brew vs iced coffee?
Cold brew = steeped cold from start. Iced coffee = hot-brewed over ice. Cold brew lower acidity (70% less), smoother. Different chemistry.
Grind size?
Coarse – like sea salt. Burr grinder French press setting. Drip-grind too fine, over-extracts, makes muddy.
Steep time?
18 hours room temp is sweet spot. Shorter = under-extracted thin. Longer = over-extracted bitter. Major brands target 18h.
How to serve?
1:1 concentrate + cold water OR milk OR oat milk. Over ice. Simple syrup if sweetening (granulated doesn’t dissolve in cold).
Sources
- Serious Eats — Cold Brew — Detailed technique.
- Stumptown Coffee — Cold Brew Guide — Third-wave bean roaster guide.
- USDA FoodData Central — Nutritional data.
Each serving (240 ml diluted) contains roughly 5 calories, 100 mg caffeine.
Please note: Contains caffeine (about 100 mg per serving). Not suitable for caffeine-sensitive individuals, pregnancy, or those with heart conditions. Consult a dietitian.
Elena Vasquez
Elena learned to bake from her abuela on a family farm in the south of Spain - wood-fired ovens, breakfast bread before sunrise, and a tia who taught her pastry between long lunches with cousins. At CookingZone she develops desserts, pastry, breakfast, healthy recipes, and beverages - from protein-rich morning bowls to classic French patisserie and viral bakery hits. She still tests every dessert on the same crew of family and friends before it makes it onto the site.
