Cold Brew Ratio Calculator
Calculate the exact coffee to water ratio for cold brew concentrate or ready-to-drink. Set your coffee weight, choose your steep style, and get precise water volumes and steep times.
Cold Brew Ratio Calculator
How to Use This Cold Brew Calculator
- Choose your brew style. "Ready-to-drink" produces cold brew you drink straight from the fridge — lighter, more refreshing. "Concentrate" produces a strong base you dilute 1:1 with water or milk before drinking, giving you more flexibility and a smaller storage container.
- Enter your coffee weight. This is the total weight of coarsely ground coffee you'll use for the batch. A common batch size is 100g (about 4–6 servings RTD) or up to 500g for a large concentrate batch.
- Select your ratio. For ready-to-drink, 1:8–1:12 works well. For concentrate, use 1:4–1:6. The calculator shows exact water volume and approximate final yield after filtering.
- Follow the steep time. The recommended steep time adjusts based on your style selection. Fridge steeping always produces the cleanest flavour and is safer for longer steeps.
- Filter and store. Pour the steeped brew through a fine mesh strainer or paper filter. Store cold brew in the refrigerator for up to 2 weeks (RTD) or 4 weeks (concentrate).
Understanding Cold Brew Coffee Ratios
Cold brew extracts coffee using cold water over an extended time rather than hot water over minutes. Because cold water is a much less efficient solvent than hot water, cold brew requires a far higher coffee-to-water ratio and significantly longer steep time to achieve comparable extraction. The coffee to water ratio for cold brew sits between 1:4 and 1:15 depending on whether you're making concentrate or a ready-to-drink brew — compared to 1:15–1:17 for typical filter methods.
The key trade-off in cold brew is between concentration and clarity. A tighter ratio (more coffee per unit of water) produces a richer, more intense brew but can become overpowering if the ratio is pushed below 1:4. A looser ratio produces a lighter, more refreshing brew but loses body and sweetness. Most specialty cold brew products on the market sit around 1:8–1:10 for ready-to-drink.
Steep time interacts directly with ratio. A longer steep at a looser ratio can produce comparable concentration to a shorter steep at a tighter ratio, but the flavour profile differs — longer steeps tend to bring out more of the coffee's acidic and fruity notes, while shorter steeps (especially for concentrate) are often sweeter and more muted. Refrigerator temperature around 4°C is optimal; room temperature brewing (18–22°C) accelerates extraction and requires less time, but can produce slightly more astringent results if left too long.
Cold Brew Ratio Reference Chart
| Ratio | Style | 100g Coffee Needs | Steep (Fridge) | Steep (Room Temp) | Best For |
|---|---|---|---|---|---|
| 1 : 4 | Concentrate | 400ml | 12–14 hrs | 8–10 hrs | Strong concentrate, dilute 1:2 |
| 1 : 5 | Concentrate | 500ml | 14–18 hrs | 10–12 hrs | Standard concentrate, dilute 1:1 |
| 1 : 8 | RTD — Strong | 800ml | 18–22 hrs | 12–14 hrs | Bold RTD, works over ice |
| 1 : 10 | RTD — Medium | 1000ml | 20–24 hrs | 14–16 hrs | Everyday cold brew, well-balanced |
| 1 : 12 | RTD — Light | 1200ml | 22–24 hrs | 16–18 hrs | Refreshing, lighter body |
| 1 : 15 | RTD — Very Light | 1500ml | 24 hrs | 18–20 hrs | Coffee-forward but very gentle |
Pro Tips for Better Cold Brew
- Use freshly roasted coffee — but not too fresh. Coffee roasted 7–21 days ago is ideal. Very fresh roasts (under 5 days) contain excess CO₂ that can make the cold brew taste sharp and over-carbonated. Stale coffee produces flat, lifeless cold brew with no sweetness.
- Grind just before brewing. The long steep amplifies any staleness in pre-ground coffee. Grinding fresh and immediately steeping maximises the flavour compounds that cold brew excels at extracting — chocolate, caramel, and low-acid sweetness.
- Use filtered water. Cold brew uses a huge volume of water relative to the coffee, so water quality matters more here than in any other brewing method. Chlorine in tap water produces off-flavours that become more pronounced in cold brew. Use filtered water.
- Don't squeeze the grounds when filtering. Pressing or squeezing the coffee grounds during filtering forces bitter, fine particles into your finished brew. Let gravity do the work through a fine mesh or paper filter, even if it takes 10–15 minutes.
- Try medium or medium-light roasts. Dark roasts can become harsh and ashy in cold brew. Medium roasts bring out more chocolate and caramel character; medium-light or light roasts highlight fruit and floral notes. Cold brew is a great way to explore a single origin coffee's full flavour range.
Frequently Asked Questions
For ready-to-drink cold brew, 1:8 to 1:12 is the sweet spot — bold enough to stand up to ice dilution, but not so concentrated it becomes overwhelming. For concentrate, 1:4 to 1:5 is standard. The "best" ratio depends entirely on how you plan to serve the cold brew and your personal strength preference.
In the refrigerator, 18–24 hours for ready-to-drink ratios, 12–16 hours for concentrate. At room temperature, reduce by 6–8 hours. Don't exceed 24 hours at room temperature — over-steeping at warmer temperatures produces bitter, over-extracted cold brew. The fridge is always the safer, more reliable method.
The most common causes of bitter cold brew are: grind too fine (switch to extra coarse), steep time too long (reduce by 2–4 hours), or water temperature too warm during steeping. Also check that you're not squeezing the grounds during filtering — this forces bitter compounds into the finished brew.
Not recommended. Medium-grind coffee over-extracts during the long cold brew steep and is very difficult to filter, resulting in cloudy, bitter cold brew with a gritty texture. Use extra coarse — similar to coarse sea salt in texture. If you only have pre-ground medium coffee, reduce steep time to 8–12 hours and use a paper filter.
Properly filtered cold brew keeps for 10–14 days refrigerated at 4°C. Cold brew concentrate lasts up to 3–4 weeks. Keep it in a sealed container to prevent it from absorbing fridge odours. The flavour gradually changes over time — most drinkers find cold brew is best in the first 5–7 days.
Cold brew concentrate has significantly more caffeine per ml than hot coffee because of the higher coffee-to-water ratio used. But ready-to-drink cold brew at a 1:8–1:12 ratio is typically comparable to or slightly higher than drip coffee — around 150–200mg per 8oz serving. Our caffeine calculator has detailed caffeine estimates for cold brew.