This guide covers the exact ratio, step-by-step method, and the three cold brew makers worth buying if you want to skip the jar-and-sieve setup.

Top pick if you want a dedicated cold brew maker: The Hario Mizudashi is the easiest entry point. Simple, compact, and it fits neatly in the fridge door. Around £30 and does exactly what it needs to.

Check Hario Mizudashi prices on Amazon UK

What You Actually Need

The honest answer: not much.

Minimum setup (no cost):

• Coarsely ground coffee
• Cold or room-temperature filtered water
• A large jar or jug with a lid
• A fine mesh sieve or kitchen paper for filtering

That is genuinely all you need to make excellent cold brew. The jar method works perfectly well. If you make cold brew every week though, a dedicated cold brew maker removes the messy filtering step and gives you a cleaner result every time.

The three worth buying:

Hario Mizudashi Cold Brew Coffee Pot is the one most home brewers start with. A mesh filter basket holds the grounds, you pour in cold water, and the fridge does the rest. No filtering, no mess. Around £30.

Check Hario Mizudashi prices on Amazon UK

Toddy Cold Brew System is a step up. It uses a thick felt filter that produces an exceptionally smooth, sediment-free concentrate. The kind of result that makes you wonder why you ever paid £5 for a cold brew at a coffee shop. Around £45.

Check Toddy Cold Brew System prices on Amazon UK

OXO Brew Compact Cold Brew Coffee Maker suits smaller batches. A drip valve at the bottom makes dispensing the concentrate clean and controlled. Good if you are making cold brew for one. Around £40.

Check OXO Brew Compact Cold Brew Coffee Maker prices on Amazon UK

The Cold Brew Ratio

Getting this right matters more than anything else.

For concentrate (recommended): 1 part coffee to 4 parts water. So 100g coffee to 400ml water. Dilute 1:1 with cold water or milk when you serve it.

For ready-to-drink: 1 part coffee to 8 parts water. Weaker, shorter shelf life (5-7 days vs 2 weeks), less flexibility.

Most people use the concentrate method. You make one batch on Sunday and have coffee on tap all week.

How to Make Cold Brew Coffee at Home

Step 1: Grind Your Coffee Coarse

Use a coarse grind, similar to what you would use in a French press. Fine grounds make the cold brew cloudy, harder to filter, and sometimes slightly bitter. Our grind size chart shows exactly where cold brew sits compared to other methods.

If you are buying pre-ground, look for bags labelled “coarse grind” or “French press.” Freshly ground is better. A medium or light roast works best for cold brew. The slow extraction brings out sweetness and body without the bitterness that heat can mask.

Buy cold brew coffee beans on Amazon UK

Step 2: Combine Coffee and Water

Add your grounds to the jar, jug, or cold brew maker. Pour in your cold or room-temperature filtered water. Give it a gentle stir to make sure all the grounds are saturated.

Do not use hot water. That is just iced coffee, not cold brew.

Step 3: Steep in the Fridge

Cover loosely and refrigerate.

• 12 hours: lighter, brighter, less intense
• 18 hours: the sweet spot for most people
• 24 hours: stronger, richer, full-bodied

18 hours is the most consistent result. If you steep on the counter at room temperature instead of the fridge, 12 hours is enough because the warmer environment speeds up extraction.

Step 4: Filter

Pour the steeped mixture through a fine mesh sieve into a clean bottle. If grounds are getting through, line the sieve with a piece of kitchen paper and pour again.

If you are using the Hario Mizudashi, Toddy, or OXO Brew, the filter is built in and this step takes about 10 seconds.

Step 5: Store and Serve

Cold brew concentrate keeps for up to 2 weeks in a sealed bottle or jar in the fridge.

To serve, dilute roughly 1:1 with cold water or milk. Taste as you go. Pour over ice. That is it.

Cold Brew vs Iced Coffee: What Is the Difference?

Cold brew is made with cold water from the start. The extraction takes 12 to 24 hours and produces a low-acid, smooth concentrate.

Iced coffee is hot brewed coffee poured over ice. It goes watery quickly, tastes more bitter, and lacks the body of cold brew.

If you have ever ordered cold brew at a coffee shop and thought it tasted completely different to your home iced coffee, that is why. For a deeper look at how cold and hot extraction differ, see our cold brew vs hot brew comparison.

Which Coffee Beans Work Best for Cold Brew?

Medium roast is the most popular choice. Chocolatey, smooth, balanced. Easy to drink on its own or with milk.

Light roast can be surprisingly good. The slow cold extraction brings out fruity and floral notes that disappear in hot brewing. Worth trying if you like more complex flavours.

Dark roast works but can taste flat or harsh. The bitterness that heat masks becomes more noticeable in cold water extraction.

Whatever you choose, buy freshly roasted beans and grind just before brewing if you can. It makes a real difference to the body of the final cup.

Find cold brew coffee beans on Amazon UK

Cold Brew FAQ

How long does cold brew last in the fridge?

Up to 2 weeks as a concentrate in a sealed container. Ready-to-drink cold brew (not concentrate) is best within 5 to 7 days.

Can I use regular ground coffee for cold brew?

Yes, but coarse ground is much better. Fine grounds make filtering difficult and can add a bitter, gritty quality to the finished brew.

Does cold brew have more caffeine than regular coffee?

The concentrate does, yes. Once diluted to drinking strength, the caffeine per cup is roughly similar to regular coffee. Drink concentrate undiluted and it will be noticeably stronger.

Do I need a special cold brew maker?

No. A jar and sieve is all you need to get started. A dedicated maker like the Hario Mizudashi or Toddy just makes the process cleaner and more consistent once you are making it regularly.

Can I make cold brew with an AeroPress?

Yes. Add coarse grounds and cold water, steep for 2 hours at room temperature, then press slowly. Quicker than a full overnight steep, though not quite as smooth. See our AeroPress recipes for the standard methods and ratios.

What is the best ratio for cold brew?

1:4 for concentrate (100g coffee to 400ml water). Start here, then adjust to taste. Most people end up somewhere between 1:4 and 1:5.

The Bottom Line

Cold brew is one of the most forgiving things you can make at home. The recipe is hard to mess up once you have the ratio right, and a batch in the fridge means you have excellent coffee ready for the whole week.

Start with the 1:4 ratio, steep for 18 hours, and taste before diluting. Most people find their preferred strength within the first couple of batches.

If you want to skip the filtering step and get a cleaner result, the Hario Mizudashi is the one to start with. If you want the smoothest possible concentrate, the Toddy Cold Brew System is the step up. Both are worth it if cold brew becomes a regular habit.

Owen has been brewing coffee at home for over a decade. He writes practical guides to help you get better results without overcomplicating things.

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