Cold Brew Ratio Calculator

About This Tool

The Cold Brew Ratio Calculator is a free tool for coffee lovers who want to make smooth, consistent cold brew at home. Cold brew coffee has exploded in popularity over the past decade, and for good reason. The long, slow extraction process produces a concentrate that is naturally sweeter, lower in acidity, and remarkably smooth compared to hot-brewed coffee. Whether you are making a small personal batch or a large pitcher for the week, getting the coffee-to-water ratio right is the foundation of a great cold brew. This calculator handles the math for you, showing exactly how much coffee and water you need based on whether you are making a concentrated extract or a ready-to-drink brew.

Concentrate vs. Ready-to-Drink

The two main approaches to cold brew produce very different results. A concentrate uses a high coffee-to-water ratio, typically between 1:4 and 1:5 by weight. The resulting liquid is very strong and is meant to be diluted before drinking, usually at a ratio of 1:1 to 1:2 with water, milk, or a plant-based alternative. The advantage of concentrate is flexibility. You can adjust the dilution to your taste, mix it with milk for an iced latte, or use it as a base for cocktails and baking. It also stores well in the refrigerator for up to two weeks. A ready-to-drink cold brew uses a lower ratio, typically 1:8 to 1:15, and produces a beverage that can be poured straight over ice without any additional dilution. It is simpler but less versatile and does not keep as long because it is already at drinking concentration.

Choosing the Right Coffee

Cold brew works with any coffee, but certain characteristics shine in this method. Medium to coarse ground coffee is essential, as a fine grind will over-extract and produce a bitter, muddy brew that is difficult to filter. Single-origin coffees from Central and South America, particularly from Colombia, Guatemala, and Brazil, tend to produce cold brews with chocolate, caramel, and nutty notes that most people find appealing. African coffees from Ethiopia and Kenya can yield fruity, wine-like cold brews that are more polarizing but fascinating when well-made. Darker roasts produce a bolder, more chocolatey cold brew, while lighter roasts preserve more of the coffee's origin characteristics and brightness. A medium roast is a good starting point if you are unsure what you prefer.

Steep Time and Temperature

Steeping time is the second most important variable after the coffee-to-water ratio. The standard range is 12 to 24 hours, with most people finding the sweet spot between 16 and 20 hours. Shorter steep times around 12 hours produce a lighter, more tea-like cold brew with less body and lower caffeine extraction. Longer steep times approaching 24 hours extract more oils, body, and caffeine, but risk pulling out harsh, bitter compounds that diminish the smooth character cold brew is known for. Room-temperature steeping extracts faster than refrigerator steeping, so if you brew on the counter, reduce your time by two to four hours compared to a fridge steep. However, refrigerator steeping produces a cleaner, more consistent result and eliminates food safety concerns about leaving coffee at room temperature for extended periods.

Filtering and Storage

After steeping, you need to separate the grounds from the liquid. A fine-mesh strainer removes most of the grounds, but for a truly clean and sediment-free cold brew, follow up with a paper filter, cheesecloth, or a dedicated cold brew filter bag. Some brewers use a French press for steeping and initial filtration, which works well for small batches. For larger batches, a nut milk bag or purpose-built cold brew maker with a built-in filter is more convenient. Store finished cold brew in a sealed glass container in the refrigerator. Concentrate keeps for up to two weeks, while ready-to-drink cold brew is best consumed within seven to ten days. The flavor will gradually become more stale and flat as it ages, so fresh batches always taste best.

Understanding Yield Loss

One aspect of cold brew that surprises many first-time brewers is the yield loss. Coffee grounds absorb roughly twice their weight in water during steeping, which means you will get significantly less cold brew out than the amount of water you put in. For example, if you steep 100 grams of coffee in 450 mL of water, you can expect to recover approximately 250 mL of concentrate after filtering. This calculator accounts for this absorption factor in its yield estimate, so you can plan your batch size accordingly. If you need a specific amount of finished cold brew, work backwards from the yield by entering a larger water amount and adjusting until the estimated yield matches your target.