The right cold brew ratio is simpler than the internet makes it sound. For concentrate, use 1 part coffee to 4 parts water by weight. For ready-to-drink, use 1 part coffee to 8 parts water. That covers 95 percent of home cold brew, and the rest is fine-tuning to taste.
Cold brew steeps for 12 to 24 hours at room temperature or in the fridge. That long contact time changes how extraction works, which is why the ratio looks so different from hot coffee.
Key Takeaways
- Concentrate ratio: 1:4 (one part coffee to four parts water by weight). Dilute with water, milk, or ice before drinking.
- Ready-to-drink ratio: 1:8. Pour straight from the jug into a glass with ice. No dilution needed.
- Steep time matters: 12-18 hours is the sweet spot. Over 24 hours can turn bitter even at a "weak" ratio.
- Coarse grind only: Cold brew needs a coarse grind (like raw sugar) to avoid muddy, over-extracted batches.
- Low-acid beans shine: Cold brew already mellows acidity. Pairing it with a naturally smooth bean like Haiti Hope Rising makes for a chocolatey, easy-drinking glass.
- Stores 7-10 days: Keep your concentrate or batch sealed in the fridge. Flavor stays best in the first 4-5 days.
- 1g water = 1 mL: 1 liter of water equals 1000g, so 1:4 concentrate uses 250g of coffee for 1L of water.
In This Guide
Cold Brew Ratio Fundamentals
Cold brew is not iced coffee. Iced coffee is hot coffee poured over ice. Cold brew is coffee steeped in cold water for many hours. The extraction is slower, gentler, and pulls fewer of the bitter compounds that come from hot water.
Because the extraction is slower, you need a higher proportion of coffee to water. That is why ratios sit in the 1:4 to 1:8 range instead of the 1:15 to 1:18 range of hot brewing. If you used a 1:16 ratio for cold brew, the cup would taste like brown water.
The two ratios you actually need to remember:
- 1:4 by weight for concentrate. You dilute this 1:1 with water or milk before drinking.
- 1:8 by weight for ready-to-drink. Pour straight into a glass over ice.
Both are weight ratios, meaning grams of coffee to grams of water. One gram of water equals one milliliter, so the math stays clean. For a one-liter batch (1000g of water), a 1:4 concentrate uses 250g of coffee. A 1:8 ready-to-drink uses 125g of coffee.
Why Weight, Not Volume
Coarse-ground coffee can compress in a measuring cup, so volume measurements drift batch to batch. A scale gives you the same cup every morning. A basic kitchen scale costs about $15.
Concentrate vs Ready-to-Drink
Which one should you make? It depends on your fridge space, how you drink coffee, and how many people are pouring from the same jug.
| Style | Ratio | Use Case | Storage |
|---|---|---|---|
| Concentrate Most Flexible | 1:4 | One household, many drink styles (with milk, water, ice, hot) | Compact, fits in fridge door |
| Ready-to-Drink | 1:8 | Daily black cold brew, grab and go | Takes more fridge space |
| Strong Concentrate Niche | 1:3 | Espresso-replacement style drinks | Smallest space but very intense |
We default to 1:4 concentrate at home. It is more flexible. One jug can become straight cold brew with ice and water, or a creamy cold brew with milk, or even a hot cold brew if you pour it into a mug and add a splash of hot water.
Quick dilution math: If you made 1:4 concentrate, pour about 1 part concentrate to 1 part water or milk in your glass. That brings the finished drink close to a 1:8 strength, which is what most coffee shops serve.
Steep Time and Ratio Interaction
Ratio and steep time work together. A 1:4 concentrate steeped for 12 hours will taste different than the same ratio steeped for 24 hours. Here is how they interact.
12 hours: Bright, clean, slightly under-extracted on darker roasts. Best for medium roasts that lean fruity.
16 to 18 hours: The sweet spot for most beans. Full body, smooth chocolate notes, low bitterness.
24 hours: Max extraction. Risk of bitterness goes up sharply past this point, especially with dark roasts. Stop at 24 unless you are testing.
Past 24 hours: The brew can turn flat and bitter at the same time. Not recommended.
Temperature changes this too. Room temperature steeps faster than fridge steeps. If you brew on the counter, lean toward 12 to 14 hours. If you brew in the fridge, lean toward 16 to 20 hours.
Immersion vs Slow Drip
There are two cold brew methods used at home and in shops. Immersion is by far the most common and the one we recommend.
Immersion (the home method): Coarse-ground coffee sits in cold water for 12 to 24 hours, then you strain it out. Equipment can be as simple as a mason jar and a fine-mesh strainer, or as fancy as a dedicated cold brew pitcher. Either works.
Slow drip (Kyoto-style): Cold water drips slowly through a bed of coffee grounds over 3 to 6 hours. Produces a cleaner, sharper cold brew. Equipment is expensive and the process is fussier, so this is mostly a coffee-shop method.
For home, stick with immersion. The result is darn close, the gear is cheap, and you can scale up to a half gallon at a time.
Simple Home Setup
A half-gallon mason jar with a coffee filter strainer is all you need. Add coarse-ground coffee, fill with cold filtered water, stir, cap, and put in the fridge for 16 hours. Strain through a fine mesh and a paper filter for a clean batch.
Bean Choice for Cold Brew
Cold brew already mellows acidity by 60 to 70 percent compared to hot coffee, according to research published by the American Chemical Society. That means even a bright coffee gets smoother. But the bean still matters.
What works best for cold brew:
- Medium to medium-dark roasts. Bring out chocolate, caramel, and nutty notes that taste great cold.
- Naturally smooth origins. Beans from Brazil, Haiti, and parts of Honduras tend to have lower acidity and fuller body, which cold brew showcases.
- Fresh coffee. Roasted within the last 3 to 4 weeks. Stale coffee tastes flat hot or cold.
What does not work as well:
- Very light roasts. Their bright, fruit-forward notes can mute or turn weirdly tart in cold brew.
- Very dark, oily roasts. They can come out flat and ashy.
If you want low acidity to begin with, our Haiti Hope Rising medium roast is one of our most popular cold brew picks. It is a natural-process Haitian coffee with chocolate and caramel notes, and the lower acidity gives the cold brew a smooth, dessert-like finish. For more on what makes a coffee low-acid, read our guide to low-acid coffee.
"He gives strength to the weary and increases the power of the weak."
Isaiah 40:29Storage and Shelf Life
Cold brew lasts longer than hot coffee, but it is not infinite. Here is what we have seen with our home batches and the trailer.
| Form | Sealed in fridge | Best window | Off-flavor signs |
|---|---|---|---|
| Concentrate (1:4) | 7-14 days | First 5-7 days | Sour, oxidized smell |
| Ready-to-Drink (1:8) | 5-10 days | First 3-5 days | Flat, papery flavor |
| Diluted with milk | 1-2 days | Same day | Same as milk spoilage |
Always seal your cold brew in a clean jar or jug. Air exposure speeds oxidation, which is the main reason cold brew loses flavor. Glass keeps the brew fresher than plastic, mostly because plastic can absorb and release oils over time.
Troubleshooting Weak, Bitter, or Sour Cold Brew
Cold brew tastes weak or watery: Most likely you used too much water for your ratio, or the grind was too coarse. Try going from 1:8 down to 1:6, or check that your grind looks like raw sugar, not gravel.
Cold brew tastes bitter: You steeped too long or used too dark a roast. Try cutting the steep time to 14 hours, or switch to a medium roast. Bitterness in cold brew almost always comes from over-extraction.
Cold brew tastes sour or sharp: You probably used too light a roast, or your beans are very fresh and need a few days of rest. Try a medium-dark roast like our House Blend for a smoother result.
Cold brew looks cloudy or muddy: Your grind is too fine. Use a coarse grind, then strain through a paper filter after the first mesh strain. The paper catches fine particles that cause murky cups.
Cold brew lacks aroma: Beans are stale, or the batch sat too long. Cold brew loses aromatics fast after day 5. Make smaller batches more often.
Smoother Cold Brew Starts With the Right Bean.
We roast small batches in Vancouver, Washington and ship within days. Try a medium roast that loves cold steeping.
Shop Fresh Coffee1:4 by weight for concentrate, 1:8 by weight for ready-to-drink. Use 1:4 if you want flexibility (dilute with water or milk per glass). Use 1:8 if you want to pour straight from the jug.
For a 1-liter concentrate at 1:4, use 250 grams of coffee. For 1 liter of ready-to-drink at 1:8, use 125 grams of coffee. One liter of water equals 1000 grams, which makes the math easy.
One gallon equals about 3785 grams of water. At a 1:4 ratio, you need about 946 grams of coffee (roughly 2 pounds). At a 1:8 ratio, use about 473 grams (roughly 1 pound).
1:4 by weight is the standard for concentrate. That is 1 gram of coffee to 4 grams of water. Some shops go as strong as 1:3 for an espresso-style concentrate, but 1:4 is the most balanced and the easiest to dilute later.
12 to 18 hours is the sweet spot for most beans. 12 hours gives a brighter cup, 18 hours gives more body and chocolate notes. Past 24 hours, the risk of bitterness goes up. Room temperature steeps faster than fridge steeps, so lean toward 12 to 14 hours on the counter.
Yes, but medium to medium-dark roasts work best. They bring out chocolate and caramel notes that taste good cold. Very light roasts can taste tart in cold brew, and very dark oily roasts can taste flat. Fresh coffee from the last 3 to 4 weeks is ideal.
Yes. Use a coarse grind that looks like raw sugar or kosher salt. A fine grind over-extracts during the long steep and produces a bitter, cloudy brew. If you do not have a grinder, ask your roaster for a French press grind.
Sealed concentrate (1:4) keeps 7 to 14 days, with the best flavor in the first 5 to 7 days. Ready-to-drink cold brew (1:8) keeps 5 to 10 days, best in the first 3 to 5 days. Once you add milk, drink within 1 to 2 days.
Sources: Specialty Coffee Association Brewing Protocols, American Chemical Society research on cold brew acidity.
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