Sightglass makes cold brew concentrate in a commercial Toddy system — five pounds of coffee, four gallons of water, a purpose-built brewer. It's a great method. It's also not something anyone needs sitting in their kitchen.
The good news: the process behind it is simple, and everything it requires has a household stand-in. Here's the same method, scaled down to fit a mason jar.
What you'll need
- A large jar or pitcher (a half-gallon mason jar works well)
- Coarsely ground coffee — coarser than what you'd use for drip, closer to breadcrumbs than sand
- Cool, filtered water
- A nut-milk bag, cheesecloth, or a clean, thin dish towel
- A fine-mesh strainer
- A measuring cup
No burr grinder? Ask your coffee shop or grocery store to grind it coarse for you — most will. Pre-ground "cold brew" bags also work.
No nut-milk bag? A few layers of cheesecloth set inside a strainer does the same job. In a pinch, a clean dish towel works too — just expect to press a bit harder when straining.
No scale? Volume measurements below get you close enough. Cold brew is forgiving.
The method
1. Combine coffee and water. In your jar, add 1 cup of coarsely ground coffee for every 4 cups of cool water. Stir to make sure all the grounds are saturated — no dry clumps floating on top.
2. Cover and wait. Put a lid on it (or plastic wrap, if the jar doesn't have one) and let it sit at room temperature or in the fridge for 12 to 16 hours. Overnight works perfectly — start it before bed, strain it in the morning.
3. Strain. Line your strainer with the nut-milk bag or cheesecloth and set it over a clean pitcher or bowl. Pour the whole mixture through slowly. Let it drip fully before squeezing — the grounds hold a surprising amount of liquid.
4. Store the concentrate. What you're left with is concentrate, not ready-to-drink coffee. It keeps in the fridge for about a week.
5. Dilute to taste. Cut it with water (or milk, if you like it that way) starting at a 1:1 ratio, then adjust. Some people like it stronger, some weaker — there's no wrong answer here. Once diluted, drink it within three days.
A few notes
- Coarse grind matters more than exact ratios. Too fine, and the coffee turns sludgy and hard to strain. Too coarse, and it under-extracts and tastes thin.
- Don't rush the strain. Squeezing the bag too early clouds the concentrate with fine sediment.
- Batch size scales linearly. Doubling the coffee and water gets you a bigger batch — the ratio is what matters, not the total volume.
That's the whole method. No brewer, no special filters — just a jar, some cloth, and time.
