Cold brew has a way of sounding like a project. In practice, it is the least demanding coffee you can make: weigh some coarsely ground beans, add cold water, and walk away. The refrigerator does the rest while you sleep. What follows is the method worth keeping between June and September — one that produces a concentrate that lives in the door of the fridge, ready to be diluted, poured over ice, or turned into something with tonic and a strip of orange peel.
Cold Brew Is Not Iced Coffee
The two get used interchangeably, but they are different drinks made different ways. Iced coffee is brewed hot, then chilled fast; it keeps the bright acidity and the aromatic top notes of a hot cup, which is exactly why some beans taste sharp over ice. Cold brew never sees heat. Water and time do the extracting instead, and the result is rounder and sweeter, with more body and a much softer finish.
That trade-off matters. You gain a drink that holds up to milk, syrup, and a long afternoon in a glass. You lose a little of the floral, tea-like top end that makes a light roasted Ethiopian so interesting hot. This is a method for beans with chocolate, nut, and caramel notes — a medium roast from Brazil or a comfortable blend does more here than a delicate competition lot.
Grind Coarse, and Coarser Than You Think
If cold brew goes wrong, nine times out of ten it is the grind. Aim for something like coarse sea salt or raw sugar: distinct fragments you can feel between your fingers, not powder and not flakes. Too fine and you get a muddy slurry that clogs the filter, takes forever to drain, and leaves a harsh, drying finish in the cup that no amount of milk will fix.
Freshly ground is best, but coarse grinds are forgiving, so grinding the night before is not a disaster. If you do not own a grinder, buy your beans at a coffee shop and ask for a French press grind — it is close enough, and far better than anything a blade grinder will produce at home. Steer clear of the supermarket shelf labelled "espresso"; you will be filtering it until midnight.
The Ratio: Work by Weight, Not by Eye
A digital scale costs very little and removes all the guesswork. Weigh the water as well as the coffee; a millilitre of water weighs a gram, so the numbers stay simple. For a concentrate you can keep in the fridge, start at 1 part coffee to 8 parts water by weight. That means 100 g of ground coffee and 800 g of cold water, which yields roughly 700 ml of concentrate once the grounds have soaked up their share.
- 1:5 — a heavy concentrate, built for milk drinks and for pouring over a lot of ice.
- 1:8 — the everyday default. Dilute to taste; keeps for days.
- 1:12 to 1:15 — ready to drink straight from the jar, no dilution needed.
Scale up in whatever jar fits in your fridge, but keep the ratio intact. A two-litre batch at 1:8 is 250 g of coffee and 2 litres of water. Write the numbers on a scrap of paper and tape it to the lid; future you will be grateful.
Steeping: Time and Temperature
Add the grounds to the water, stir once so every particle is wet, and cover the jar. Grounds that sit dry on top never contribute anything, which is why a quick stir at the start matters more than any other bit of handling.
Room temperature or fridge
On the counter, most batches are ready in 14 to 18 hours. In the fridge, give it 18 to 24. The cold version extracts more slowly and more selectively, giving a cleaner cup with less of the papery edge that long room-temperature steeps can pick up. It is also far more forgiving if you oversleep. For a first batch, use the fridge.
How to know it is finished
Taste it. Spoon out a little, dilute it with an equal amount of water, and let it cool if needed. If it tastes sweet and long, with a finish that fades gently, it is done. If it is drying or astringent at the edges, filter it now — the grounds are giving up things you do not want.
Filtering Without the Mud
Patience here pays off more than equipment. A two-stage filter gives you a clear, almost tea-like liquid that keeps well, while a lazy single pass leaves sludge at the bottom of every glass.
- Set a fine mesh sieve over a large jug or bowl and line it with a paper filter. Rinse the paper with a splash of water so it does not taste of itself.
- Pour the steep in slowly. Let gravity do the work — pressing or squeezing the grounds forces fine particles through and adds bitterness.
- Give the filter time. A full batch can take 20 minutes to drain; walk away and do something else.
- If the result is still cloudy, pass it through a fresh paper filter a second time.
- Let the filtered brew sit for half an hour, then decant it off any sediment that has settled at the bottom.
No paper filters? A nut milk bag or a clean cotton cloth works. A French press is a decent standby, but stop at the plunger rather than pressing hard, and pour through a paper filter afterwards if you want it bright and clear.
Serving It Cold, and Diluted Properly
Chill the concentrate before it meets ice. A cold liquid melts ice slowly, so you get a stronger drink for longer instead of a watery one ten minutes in. Use large cubes if you have them, and pre-chill the glass.
For a standard glass, one part concentrate to one part cold water is a good opening move. For something lighter and more refreshing, push it to one part concentrate and two parts water or sparkling water. With cold milk, keep it at one part concentrate to two parts milk; the coffee stays present instead of retreating behind dairy. A pinch of salt sharpens the sweetness, and a strip of orange peel pressed over the top does more for a summer glass than any syrup. If you want sweetness, dissolve sugar into a little hot water first and add syrup — granules will not dissolve in a cold drink.
Store, Adjust, Repeat
Keep the concentrate in a sealed jar in the fridge, labelled with the date, and drink it within about a week; it fades rather than spoils, and some batches taste best in the first few days. When you make the next one, change a single variable: grind finer or coarser first, since that has the biggest effect, then shorten or lengthen the steep, then adjust the ratio. Keep the note on the lid. Three or four batches in, you will have a house recipe you can make without thinking — which is precisely the point of cold brew.
Photo: stevepb / Pixabay
