Cold Brew Coffee Ratio: The Complete Guide

How much coffee and water to use — and how to choose the right ratio for how you brew

What Is a Cold Brew Ratio?

A cold brew ratio describes how much coffee you use relative to water. It’s written as two numbers separated by a colon — for example, 1:5 means one part coffee for every five parts water.

The ratio is the single biggest lever you have over the final flavor. Too little coffee (a high ratio like 1:20) and the result tastes watery and flat. Too much coffee (a very low ratio like 1:3) and it’s harsh and unpleasant to drink straight. The right ratio depends on whether you’re making a concentrate or a ready-to-drink brew, and how strong you personally like your coffee.

Unlike hot brewing methods where brew time is short and temperature drives extraction, cold brew steeps for 12–24 hours. The ratio stays constant through that window, so getting it right before you start is more important than with most other brewing methods.

Concentrate vs. Ready-to-Drink

Before choosing a ratio, decide which type of cold brew you’re making. This determines the entire ratio range you’re working within.

Most home brewers make concentrate. It’s more efficient, and diluting 1:1 with cold water or milk takes only a few seconds. Ready-to-drink is a good choice if you want a simpler routine or you’re brewing for people who’ll pour it straight.

Cold Brew Ratio Chart

This chart covers the full range of practical cold brew ratios, from a very strong concentrate down to light ready-to-drink. All ratios are by weight — grams of coffee to grams of water.

How to Measure Cold Brew Ratio in Grams

Measuring by weight is the most consistent way to hit your ratio every time. Volume measurements — cups, tablespoons — vary depending on grind size and how tightly the coffee is packed. A gram is always a gram.

All you need is a basic kitchen scale. Weigh your coffee first, then weigh your water. Since water has a density of approximately 1g/ml, grams and milliliters are interchangeable for water — 500g of water is 500ml of water.

Note: the table below shows brewing water only. Actual jar fill level will be higher once grounds are added — they take up volume and absorb some water during steeping.

For a different container size or ratio, the cold brew ratio calculator handles the math automatically and accounts for water absorbed by the grounds.

How to Choose the Best Cold Brew Ratio

There’s no single “correct” ratio — it depends on how you drink cold brew and how you brew it. A few questions help narrow it down quickly.

Are you diluting before drinking?

If yes, use a concentrate ratio (1:4 to 1:8). The most common starting point is 1:5, diluted 1:1 with cold water. If no, use a ready-to-drink ratio (1:12 to 1:15).

How strong do you like your coffee?

If you drink your coffee strong and dark, start at 1:5 for concentrate or 1:12 for ready-to-drink. If you prefer something lighter and smoother, start at 1:6 or 1:8 for concentrate, or 1:15 for ready-to-drink.

Are you adding milk or a milk alternative?

Milk dilutes the concentrate just like water, so adjust accordingly. A 1:5 concentrate diluted 1:1 with oat milk will taste similar to a 1:5 diluted with water, but slightly creamier and a bit less intense.

Are you new to cold brew?

Start at 1:5 for concentrate and taste it after diluting 1:1. That single batch will tell you whether you want to go stronger or weaker on the next one. Most people land between 1:5 and 1:8 for concentrate.

Adjusting Your Ratio Based on Taste

After your first batch, taste the finished cold brew and use these adjustments on the next one. Small ratio changes make a noticeable difference.

Does Ratio Affect Steep Time?

Ratio and steep time work together, but they’re separate variables. Changing your ratio doesn’t require changing your steep time — both affect strength in different ways.

Steep time primarily affects extraction depth: how much flavor is pulled from the grounds. Ratio affects concentration: how much coffee flavor is present relative to the water volume. A 1:5 ratio steeped for 12 hours will taste different from a 1:5 ratio steeped for 20 hours, even though the ratio is identical.

For most home brewers, 14–18 hours in the fridge is a reliable window that works across ratios from 1:4 to 1:8. Adjust steep time to dial in extraction depth; adjust ratio to dial in strength and concentration.

Cold Brew Ratio: Common Questions

• What is the best cold brew coffee ratio?

  The most widely used ratio is 1:5 for concentrate — one part coffee to five parts water by weight. It produces a strong, flavorful concentrate that dilutes well. If you prefer something lighter, 1:6 or 1:8 are good alternatives. For ready-to-drink cold brew, 1:12 to 1:15 is the standard range.

• What is the cold brew concentrate ratio?

  Cold brew concentrate is typically made at a 1:4 to 1:8 ratio. The 1:5 ratio is the most common starting point. All concentrates are meant to be diluted before drinking — usually 1:1 with water or milk to reach a typical drinking strength.

• How do I measure cold brew ratio in grams?

  Weigh your coffee on a kitchen scale, then weigh your water. At a 1:5 ratio, use 1 gram of coffee for every 5 grams of water. Water weighs approximately 1g per milliliter, so 850g of water equals 850ml. The cold brew ratio calculator can convert any ratio into exact gram, ounce, or milliliter amounts for your jar size.

• What ratio should I use for ready-to-drink cold brew?

  Use a 1:12 to 1:15 ratio for cold brew you’ll drink without diluting. A 1:15 ratio is close in strength to a regular cup of drip coffee. A 1:12 ratio is slightly stronger but still smooth enough to drink straight over ice.

• Does cold brew ratio affect caffeine?

  Yes — a stronger ratio produces a more caffeine-dense concentrate per ounce. However, once diluted to drinking strength, the caffeine per serving ends up similar to regular coffee. Total caffeine in a batch is determined mostly by how much coffee you used overall, not the ratio alone.

• Can I use cups instead of grams for cold brew?

  You can, but weight measurements are more consistent. Coffee volume varies with grind size and packing, so a cup of coarsely ground coffee weighs noticeably less than a cup of finely ground coffee. Measuring in grams removes that variable. If you prefer to work in cups, the cold brew ratio calculator handles all unit conversions.

More Cold Brew Guides

If you’re working on your process beyond just the ratio, these guides cover the rest of the brewing workflow in detail.

For a full step-by-step walkthrough of the brewing process — equipment, grind size, steep time, and filtering — see how to make cold brew coffee. For quick answers on common questions about cold brew, see the cold brew FAQ page.