How do I make cold brew coffee?

Cold brew is not iced coffee. Iced coffee is brewed hot and chilled; cold brew never gets hot at all, which changes what's extracted. Without heat, fewer of the acidic and bitter compounds dissolve, so the result is smoother and sweeter — and takes twelve hours instead of four minutes.

What you'll need

• Large jar or jug
• Coarsely ground coffee
• Fine mesh sieve and a paper filter or muslin
• Scales
• Cold brew filter bag (optional)

Step by step

1. Grind coarse — coarser than for a cafetière.The long steep does the work. Fine grounds turn muddy and are very hard to filter out.
2. Use about 100g of coffee per litre of cold water for a concentrate.That's roughly double a hot brew ratio, because you'll dilute it before drinking.
3. Combine coffee and cold water in a jar and stir so all the grounds are wet.Dry clumps floating on the top contribute nothing.
4. Cover and refrigerate for 12–18 hours.Room temperature works and is faster (8–12 hours) but the fridge is safer and gives a cleaner result.
5. Strain through a fine sieve to remove the bulk of the grounds.Don't press or squeeze the grounds — that pushes fines and bitterness through.
6. Filter again through a paper filter or muslin for a clear result.The second filtration is what separates good cold brew from silty cold brew. It's slow; leave it.
7. Store the concentrate in a sealed bottle in the fridge and dilute to taste.Start at 1:1 with water or milk and adjust. Keeps well for around two weeks.

Tips

• Cold brew is a good use for a medium or medium-dark roast; very light roasts can taste flat and under-developed without heat.
• Serve over ice made from cold brew rather than water if you don't want it diluting as it melts.
• The grounds are much harder to filter than hot-brew grounds. A cold brew filter bag saves considerable mess and is worth the small cost.
• Cold brew is often noticeably higher in caffeine per serving than expected, because the concentrate is strong. Dilute properly.

Common mistakes

• Grinding too fine — Nearly impossible to filter, and it turns muddy and bitter despite the cold.
• Squeezing the grounds when straining — Forces fines and harsh compounds into the finished brew.
• Steeping for far too long — Beyond about 24 hours it does start to develop bitterness, even cold.
• Expecting it to taste like hot coffee — It's a different extraction — smoother, sweeter, less acidic. That's the point.

Questions people ask