Cold Brew Ratio Calculator

It depends on whether you are making concentrate or ready-to-drink coffee. For concentrate, 1:4 to 1:6 by weight, with the National Coffee Association citing 1:4 to 1:5. For coffee you will drink straight from the jug, 1:8 to 1:12. The most common mistake is brewing at a concentrate ratio and then drinking it undiluted, which produces something roughly four times the strength of drip coffee.

12 to 16 hours in the refrigerator for a ready-to-drink ratio around 1:8, and 18 to 24 hours for a strong concentrate at 1:4. Stronger ratios need longer because there is less water per gram of coffee to carry the solubles away. At room temperature, 8 to 12 hours is enough, though the result is harsher. Past 24 hours the brew turns bitter and woody without gaining useful strength.

Divide the difference between your target and your brewing ratio by the brewing ratio. For a 1:4 concentrate taken to drip strength at 1:16, that is three parts water to one part concentrate. For a 1:5 concentrate to the same target, 2.2 parts. If you want a robust iced coffee at 1:12 rather than drip strength, a 1:4 concentrate needs two parts water.

It is consistent, but it does not give you a drip-strength cup. A 1:4 concentrate diluted one to one becomes 1:8, which is about twice the strength of drip coffee at 1:16. That is the intended ready-to-drink strength, and the missing assumption is ice: a full glass of ice adds another 50 to 100 g of water as it melts and finishes the dilution. Drunk without ice, one-to-one cold brew tastes overwhelming.

Because the grounds keep roughly twice their own weight in water, and cold brew uses an unusually large dose. At 1:5, brewing 500 g of water over 100 g of coffee returns only about 300 g — a 40% loss. A drip brew at 1:16 loses only about 11%. This is normal and unavoidable; pressing the grounds recovers a little more liquid but pulls fines and harsh compounds through with it.

Coarse, comparable to French press or slightly coarser. Cold water extracts slowly, and the long steep is what compensates. A fine grind over 16 hours over-extracts into bitterness and, more practically, creates a sludge that is extremely difficult to filter. Strain through fine mesh first, then paper or cloth if you want a clean cup, and do not force the paper stage.

The concentrate certainly is, because the ratio is so much tighter — typically 100 to 200 mg per 6 oz before dilution, against 80 to 120 mg per 8 oz for drip. Once diluted to drinking strength, cold brew is broadly comparable to drip coffee. The practical risk is that a concentrate makes it very easy to drink several servings’ worth without realising, particularly when it is mixed into milk.

Concentrate keeps about two weeks refrigerated in a sealed container. Once diluted, three to four days before it starts to taste flat and papery. Cold brew is more stable than hot coffee because far fewer volatile aromatics and acids are extracted in the first place, which is the same reason it tastes smoother and less bright.

Yes, and it extracts faster — 8 to 12 hours rather than 12 to 24. The trade-off is a harsher, less sweet cup, since warmer water pulls more of the bitter compounds that cold steeping leaves behind. There is also a modest hygiene consideration in leaving a wet slurry of organic matter out for half a day. If you do it, strain on schedule and refrigerate straight away.

Measurably, though the difference is smaller than marketing suggests. Cold water extracts fewer of the acids that are readily soluble at brewing temperature, so cold brew typically measures a few tenths of a pH unit higher than a hot brew of the same coffee. Whether that translates to less digestive discomfort varies by person, and the smoothness people notice owes as much to the missing bitter compounds as to the acidity itself.