Wellness Origin HubCold brew coffee in a jar: ratio, grind and steeping time
How to make cold brew coffee in a jar with a simple 1 to 8 ratio, a coarse grind and a 12 to 18 hour steep in the fridge, then dilute it to taste.
Cold brew coffee is coarsely ground coffee steeped in cold water for 12 to 18 hours, then strained. Use about 100 g of coffee to 800 ml of water, a ratio of roughly 1 to 8, and you get a strong concentrate that you dilute half and half with water or milk over ice. It tastes smooth, chocolatey and low in bitterness, and all it needs is a jar and a sieve.
Steeping coffee in cold water is not new. Japanese slow-drip "Kyoto-style" coffee has been made for generations, and cold-steeped coffee concentrates have long been sold in the United States. The modern cold brew, steeped in bulk and sold over ice, became a café staple in the US in the 2010s. Made at home, it is one of the cheapest ways to have good iced coffee all week.
How to make it
- Grind the coffee coarse, like rough sea salt or breadcrumbs. Pre-ground filter coffee works but gives a muddier result.
- Put the coffee in a large clean jar, pour in the cold water and stir so all the grounds are wet.
- Cover and leave in the fridge for 12 to 18 hours. On the counter, 12 hours is usually enough.
- Strain through a fine sieve lined with a paper coffee filter or a clean thin cloth. Let it drip; do not squeeze the grounds.
- Pour into a clean bottle and keep it in the fridge.
- To serve, fill a glass with ice, add one part concentrate and one part cold water or milk, and stir.
Ratio, grind and time at a glance
| Choice | Starting point | If it tastes weak | If it tastes harsh or bitter |
|---|---|---|---|
| Ratio (coffee to water) | 1 to 8 for concentrate | Use more coffee, 1 to 6 | Dilute more when serving |
| Grind | Coarse, like breadcrumbs | Grind a little finer | Grind coarser |
| Steep time (fridge) | 12 to 18 hours | Leave it longer, up to 20 | Cut it back to 12 |
| Dilution | 1 part concentrate, 1 part water or milk | Less water | More water or milk |
Change one thing at a time. Most problems are solved by the grind or the steep time.
Tips for the best flavour
- Choose medium or darker roasts. Cold water pulls out chocolate and nutty notes more than bright fruity ones. Light roasts can taste thin and sour as cold brew.
- Grind it fresh and coarse. A fine grind clogs the filter and makes a cloudy, bitter brew. A burr grinder gives the most even result; see our pick of burr coffee grinders.
- Use filtered water. Coffee is almost all water, and a strong chlorine taste comes straight through.
- Strain twice. A sieve first to take out the bulk, then a paper filter for a clean, clear brew without sediment.
- Dilute to taste. The concentrate is strong. Start with half and half and adjust. Over a lot of ice, a little less water is fine because the ice melts.
If you would rather not juggle jars and filters, a dedicated pitcher with a mesh insert makes the straining step much easier. We compare a few in the best cold brew makers.
Variations
- Cold brew with milk: dilute with cold milk or oat milk instead of water for a smooth iced latte.
- Sweet cream: stir a little maple syrup and a splash of cream or vanilla into the milk before pouring.
- Spiced: add a cinnamon stick or two crushed cardamom pods to the jar while it steeps.
- Coffee ice cubes: freeze some diluted cold brew in an ice tray so the drink does not get watery as it melts.
- Condensed milk: a spoonful of sweetened condensed milk stirred in gives you something close to the drink in our Vietnamese iced coffee recipe, though that one uses a hot phin brew.
Storage
Strained cold brew concentrate keeps in a closed bottle in the fridge for about a week to ten days. The flavour is best in the first few days and slowly goes flat after that. Do not store it with the grounds still in; it keeps extracting and turns bitter and woody. Dilute only what you are about to drink.
Questions people ask
Does cold brew have more caffeine than regular coffee?
The concentrate is strong, but once diluted half and half, a glass usually has a similar amount of caffeine to a mug of filter coffee, depending on the beans and how much you dilute it. If you are counting, our guide to how much caffeine is too much explains the daily limits.
Is cold brew less acidic?
Cold brew generally tastes less sharp and bitter than hot coffee, and many people find it gentler. The measured difference in acidity is smaller than the taste suggests, so if you have reflux, treat it like any other coffee and see how you get on.
Can I make cold brew with decaf?
Yes, the method is the same. Decaf beans make a smooth, mellow cold brew that you can drink in the evening.
Photograph: AI-generated image
