The grind

It's best to go for a coarse, a bit coarser than a normal filter grind. Grind size is difficult to communicate in words, but it should feel like coarse sand.

The ratio

The key to cold brew is the ratio of coffee to water and how you plan to drink it.

• Black - if you like it black go for a 80g/l ratio
• White - if you’re planning on adding milk to your brew, you’ll want to make a stronger concentrate. A 120g/l will taste good when diluted with around 1/3 milk.

The pour

Grind your coffee and put it into the receptacle and pour the water in. You’ll want to weigh the water if it’s a small amount, but at larger volumes a jug with volume markers should be accurate enough. All the coffee should be wet, so make sure you pour around in circles and don’t leave any clumps. If you fail to get it all wet, you can give the slurry a gentle stir, but don't mix or agitate it.

The wait

Stick the receptacle in the fridge for at least 24 hours. Once that's done strain/plunge the coffee. It's OK at this stage but if you had a find grind you can run it through the paper filter. Seal up your receptacle and keep it in the fridge. If it’s properly sealed and stored in glass, it should keep for 1-2 weeks.