Cold Brew Ratio Calculator

How Cold Brew Ratios Work

Cold brew coffee is made by steeping coarsely ground coffee in cold or room-temperature water for an extended period, typically 12 to 24 hours. The coffee-to-water ratio is the single most important variable that determines the strength and flavor of your final drink. A concentrate ratio of 1:5 (one part coffee to five parts water) produces a strong base meant to be diluted before drinking. A ready-to-drink ratio of 1:15 creates a lighter brew you can enjoy straight from the fridge. Understanding these ratios lets you consistently produce cold brew that matches your taste preferences without guesswork.

Cold Brew Concentrate vs Ready-to-Drink

Concentrate cold brew uses significantly more coffee grounds per volume of water, yielding a bold, syrupy liquid that stores well in the fridge for up to two weeks. When ready to drink, dilute it 1:1 with water for a standard cup, or 1:2 for a lighter flavor. Ready-to-drink cold brew, on the other hand, is brewed at a weaker ratio so it can be consumed immediately without dilution. Choose concentrate if you want flexibility — you can mix it with milk, flavored syrups, or sparkling water. Choose ready-to-drink if you prefer a grab-and-pour morning ritual with no extra steps.

Steep Time and Grind Size Guide

The ideal steep time for cold brew ranges between 16 and 18 hours at room temperature or in the refrigerator. Steeping under 12 hours produces a weak, under-extracted brew that tastes watery and sour. Going beyond 24 hours risks over-extraction, resulting in harsh, bitter flavors. For grind size, always use a coarse grind — similar in texture to raw sugar or coarse sea salt. Fine grinds lead to over-extraction and a gritty, unpleasant sediment in your final drink. If using a French press, the built-in mesh filter works well with coarse grounds. For mason jar brewing, use a cheesecloth or fine-mesh strainer to filter after steeping.

Why You Get Less Cold Brew Than You Poured In

Here is the number almost every cold brew calculator leaves out: coffee grounds keep roughly 2 grams of water for every gram of coffee, and that water never comes out of the filter. It is why a first batch always looks short.

Work an example at 1:4. You use 250 g of coffee and 1,000 g of water, so 1,250 g goes into the vessel. The spent grounds hold back about 250 × 2 = 500 g, leaving roughly 750 g of concentrate — not the 1,000 g the ratio implies. Diluted 1:1 to serve, that is about 1.5 litres of drinkable cold brew, not 2. Two practical consequences. If you are brewing to fill a specific bottle, size the batch on the yield, not the water figure: divide your target concentrate volume by about 0.75 to find the water to start with. And resist wringing the filter bag to reclaim that 500 g — the last liquid squeezed out of saturated grounds carries the harshest, most astringent compounds, which is a common cause of a bitter batch that the ratio alone cannot explain. Coarser grinds hold slightly less water than fine ones, so a very fine grind both over-extracts and shrinks your yield. Brewing-ratio reference material is published by the Specialty Coffee Association. Updated 2026-08-25.

Tips for the Best Cold Brew at Home

Use freshly roasted coffee beans ground just before brewing for maximum flavor. Filtered water makes a noticeable difference since cold brew extracts fewer volatile compounds than hot brewing, allowing water quality to shine through. Store your finished cold brew in a sealed glass container in the refrigerator. Concentrate keeps for 10 to 14 days, while ready-to-drink batches are best consumed within 5 to 7 days. If you enjoy iced cold brew, account for ice melt by making your concentrate slightly stronger — this calculator includes an ice compensation option to handle that automatically. Experiment with different coffee origins to discover your preferred flavor profile.