Cold brew is not iced coffee, and the difference matters. Recipe, timings, and why the Japanese method may give you a better result in a fraction of the time if your coffee is any good.
Cold brew is not iced coffee
It's the most widespread confusion and worth clearing up first, because these are three different drinks:
- Cold brew — coffee extracted with cold or room-temperature water over 12 to 24 hours. It never sees heat.
- Iced coffee — coffee brewed hot and cooled afterwards, usually over ice. Cooling tends to accentuate bitterness.
- Japanese method — brewed hot directly onto ice, so it chills instantly.
Cold brew takes a night; the Japanese method takes three minutes. And for specialty coffee, the Japanese method usually gives the better result, as we'll see.
What the cold does
Temperature governs which compounds dissolve and how fast. In the cold, acids and some bitter compounds extract far less readily, while sugars and part of the aromatics do make it into the water, only slowly.
Hence the characteristic impression: sweet, smooth, no edge. One point of precision almost nobody makes: the pH of cold brew barely differs from hot coffee. It isn't that there's less acid, it's that you perceive less of the specific acids that give the sharp bite. For anyone avoiding coffee on stomach-acidity grounds, the real difference is smaller than the marketing suggests.
Concentrate recipe
- Coffee: 100 g coarsely ground per litre of water (a 1:10 ratio). This is a concentrate, to be diluted afterwards.
- Water: cold or room temperature, filtered if yours is hard.
- Mix making sure all the coffee is wetted. Stir.
- Steep: 14-18 hours in the fridge. Out of the fridge, 12 is enough, but the result is less clean.
- Filter: first through a fine sieve to remove the coarse grounds, then through paper or muslin.
- Serve diluted to taste: one part concentrate to two or three of water or milk.
If you'd rather skip the dilution step, use 60 g per litre and it's ready to drink.
How long it really keeps
You'll often read that cold brew lasts a fortnight in the fridge. Technically it doesn't spoil, but from around day four or five it loses a lot of aroma and settles into a flat, woody note.
Sensible approach: make three or four days' worth, in a well-sealed glass bottle filled to the top, to leave as little air inside as possible.
The Japanese method, the quick alternative
If you have a V60 and a specialty coffee, this is worth doing:
Brew a normal pour-over but replace 40 % of the water with ice in the jug. So for 500 g total: 200 g of ice in the jug and 300 g of hot water poured over the top, with the same amount of coffee you'd use hot.
The coffee falls hot onto the ice and chills instantly. Because the aromatics have no time to evaporate, it keeps all the floral and fruity character that cold brew leaves behind. It takes as long as a normal coffee.
Cold brew for sweetness and body. Japanese for aroma and acidity. With a fine single origin, the Japanese method usually wins.
Watch the caffeine
A 1:10 concentrate carries far more caffeine per millilitre than normal coffee. Drink it undiluted because "it tastes mild" and you can take on three times what you think — precisely because it doesn't taste strong. That's the standard cold brew trap.
Which coffee to use
It works best with light or medium roasts and fruity profiles; very dark roasts give a cold brew that leans too far towards liquorice. Our Colombia, with its caramel and red fruit backbone, works well both as cold brew and Japanese.
A note for anyone in a warm climate: in summer coffee sitting in a cupboard degrades considerably faster than general guides suggest, and that affects how much you should buy at once. We explain it in the article on specialty coffee in Almería and in the storage guide.
For coarse grinding without extra equipment, a French press works perfectly well as a steeping vessel. Whole bean coffee is in the shop.
