Can You Cold Brew Coffee Bags?

Yes, you can cold brew coffee bags, as long as you use enough of them. Put five of our coffee bags in 400ml of cold filtered water, leave the jar in the fridge for 12 to 18 hours, then lift the bags out. Each bag holds only 10g of coffee, about a twelfth of what a litre of cold brew needs, so one bag in a jug makes a very weak drink.

Cold brew coffee bags can mean two things. Some brands sell bags made for cold brew, filled with around 50g of coffee. This guide covers the other kind, the single-serve bags of 10g that make one hot mug. If you are not sure which you have, our guide to what coffee bags are explains the difference.

Why one coffee bag is not enough

A hot cup uses one 10g bag in about 230ml of water, which is 43g of coffee per litre. Cold water extracts slowly, so cold brew needs far more. Our cold brew coffee beans page gives 1:8 for a drinking-strength brew, which is 125g per litre. One bag in a litre jug gives 10g per litre. That is under a quarter of a hot cup's strength and about a twelfth of a proper cold brew.

How many coffee bags per jar

Start from the weight of coffee and the sums are quick, because every bag is 10g.

Concentrate packs the same bags into half the water, and you dilute it one to one before drinking. Our guide on how to make cold brew concentrate covers the dilution. The grounds hold on to some of the water, so you will pour out a little less than you put in.

How to cold brew coffee bags

Five bags in one jar looks excessive the first time. Do it anyway. You need a jar or jug with a lid, a spoon and some room in the fridge.

1. Count out five coffee bags for every 400ml of water.
2. Put the bags in a clean jar and pour on cold filtered water.
3. Push the bags under with a spoon until each one is soaked through.
4. Put the lid on and leave the jar in the fridge for 12 to 18 hours.
5. Lift the bags out and press them against the side of the jar with the back of the spoon.
6. Pour over ice and drink, and keep the rest sealed in the fridge.

Cold brew is mostly water, so use cold filtered water. Our post on the best water for brewing coffee explains why distilled water gives a weak, bitter cup. The 12 to 18 hours is our guidance for beans. These bags are filled for hot water, so we would taste the jar at 12 hours and again at 18. If it is thin, add a bag next time rather than steeping longer.

Cost per litre

At the ten-pack price of £6.95 a bag costs about 70p, so a litre at 1:8 takes 12 or 13 bags and comes to roughly £8.70. The pack of 30 at £20.55 brings that to about £8.60. The box of 300 at £119.95 brings it down to £5.00. The same litre made from our whole beans costs just over £4, because a 500g bag at £16.95 covers four litres at the same ratio. Bags are tidy. Beans are cheaper.

Storing cold brew

Pour it into a sealed bottle and keep it in the fridge. It lasts around 7 to 14 days, though by day ten the flavour has usually flattened, so finish a batch inside a week if you can. Our guide on how long cold brew lasts covers fridge temperatures. If you want iced coffee without the wait, read how to make iced coffee at home.

Which coffee bags to use

Bags of Gold is a medium roast at strength 3 out of 5, with notes of chocolate and caramel. Simmer Down Decaf is a Swiss Water Process decaf from Cajamarca in Peru, with notes of vanilla fudge and caramelised biscuit. Both hold 10g a bag, so the table above works for either. For decaf cold brew from beans, our guide on how to make decaf cold brew has the ratios. You will find both bags in our coffee bags collection. A ten-pack makes about 800ml, and we would buy one of those before committing to a box of 300.

Cold brew coffee bag questions

How many coffee bags do you need for cold brew?

Use five bags for 400ml of water, or 12 to 13 bags for a litre. Each of our bags holds 10g of coffee, and drinking-strength cold brew uses 1:8, which is 125g of coffee per litre. Use fewer bags in the same water for a lighter glass.

Can you cold brew a single coffee bag?

You can, but only in a small glass. One 10g bag supports about 80ml of water at drinking strength. In a full jug it gives roughly a twelfth of the coffee a cold brew needs. Add bags as you add water.

How long do you steep coffee bags for cold brew?

Steep them in the fridge for 12 to 18 hours. That range was written for beans, so taste the jar at 12 hours and again at 18. Past 24 hours, cold brew tends to turn harsh instead of stronger. If the first jar is thin, add a bag next time rather than steeping longer.

Can you make cold brew concentrate with coffee bags?

Yes, but it takes a lot of bags. Concentrate uses 1:4, so five 10g bags go in 200ml of water and a litre needs 25 bags, about £17 at ten-pack prices. Dilute it one to one before drinking. For big batches, beans cost far less.

How long does cold brew from coffee bags last?

In a sealed bottle in the fridge it lasts around 7 to 14 days. By day ten the flavour has usually flattened, so aim to finish a batch within a week. A fridge at the warm end of the 0 to 5 degrees centigrade range shortens that window.