Cold Brew Steep Timer

Common uses for a cold brew steep timer

Overnight batch for the week
Concentrate for iced coffee
Lower-acidity coffee
Making cold brew for a crowd

Cold brew extracts without heat, which is why it takes hours rather than minutes and why it tastes so different from iced filter coffee. Low temperature extracts less of the acidity and bitterness that hot water pulls out quickly, giving a rounder, sweeter cup — and it is why steep time, not temperature, is the variable you control.

Room temperature extracts faster than the refrigerator, so the two need different times: broadly twelve to eighteen hours on the counter, and sixteen to twenty-four in the fridge. Past that the returns diminish and the brew starts picking up woody, papery flavours. A coarse grind is essential — fine grounds over-extract even at low temperature, and they make filtering slow and messy.

Room temperature or refrigerator

Both work. Room temperature is faster and generally extracts a fuller body; the fridge is slower, cleaner-tasting, and avoids leaving coffee at ambient temperature overnight, which some people prefer for a batch that will be kept for days.

If you steep at room temperature, refrigerate the brew as soon as you have filtered it. The finished coffee is a food, and leaving it on the counter is the part of this process most worth being careful about.

Concentrate versus ready-to-drink

A concentrate is brewed at a much tighter ratio — commonly around 1:5 coffee to water by weight — and diluted to taste, typically one part concentrate to one or two parts water or milk. Ready-to-drink is brewed nearer 1:15 and needs no dilution.

Concentrate is the more practical choice for a batch: it takes less fridge space and lets you adjust strength per glass. Filter it thoroughly through a fine mesh or paper, because grounds left in the jug carry on extracting for as long as they are there.

Filtering, and what to do with the grounds

Filter through a fine mesh first to catch the bulk, then through paper if you want a cleaner cup. Skipping the second pass leaves fine sediment that settles in the jug and keeps extracting, which is why a batch can taste noticeably harsher on day three than on day one even when it was filtered.

Steep times are conventional starting points rather than published standards. Use a coarse grind for all of them.

Cold brew steep times and ratios
Setup	Ratio (coffee:water)	Steep time
Room temperature, concentrate	1:5	12–15 h
Room temperature, ready-to-drink	1:15	14–18 h
Refrigerator, concentrate	1:5	16–20 h
Refrigerator, ready-to-drink	1:15	18–24 h

Refrigerate the finished brew immediately after filtering, and use it within about a week.
Steeping well past these ranges brings out woody, papery flavours rather than more strength.

Source: Coffee Standards — brewing ratio and extraction principles

Sources

Coffee Standards — brewing ratio and extraction principles , Specialty Coffee Association — accessed 2026-07-28

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❓ Frequently Asked Questions

How long should cold brew steep?

Broadly twelve to eighteen hours at room temperature, or sixteen to twenty-four in the refrigerator, since cold slows extraction. These are conventional ranges rather than published standards. Past them the brew gains woody, papery flavours rather than strength.

Room temperature or in the fridge?

Both work. Room temperature is faster and fuller-bodied; the fridge is slower and cleaner-tasting, and avoids leaving coffee at ambient temperature overnight. If you steep on the counter, refrigerate the brew as soon as it is filtered.

What ratio should I use for concentrate?

Around 1:5 coffee to water by weight for concentrate, diluted one part to one or two parts water or milk when serving. For ready-to-drink, brew nearer 1:15 and skip the dilution. Concentrate stores in less fridge space and lets you set strength per glass.

Why does my cold brew taste bitter?

Usually the grind is too fine, or the grounds were left in after the steep. Cold water extracts slowly, but a fine grind over-extracts even so, and any grounds still in the jug keep working. Use a coarse grind and filter thoroughly at the end of the steep.

How long does cold brew keep?

About a week refrigerated. Concentrate keeps a little better than diluted brew because there is less water in it. Filter it properly first — grounds left in the jug both over-extract and shorten how long it stays pleasant.

Can I just steep it longer to make it stronger?

Only up to a point. Strength is set mainly by the ratio, not the clock. Doubling the steep time gives you a woody, flat cup rather than twice the coffee — if you want it stronger, use more coffee.