Cold Brew Coffee at Home: Easy Recipe & Storage Tips
Cold brew coffee is smoother, less acidic, and naturally sweeter than hot-brewed coffee — and you can make it at home with almost no special equipment. All it takes is coarsely ground coffee, cold water, and a little patience.
In this guide you'll learn the exact ratios and brew times, how to store your cold brew so it stays fresh for up to two weeks, and a few easy variations to try once you've nailed the basics.
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What Makes Cold Brew Different?
Cold brew isn't just iced coffee. Regular iced coffee is brewed hot and then cooled down — which can make it bitter and watery. Cold brew, by contrast, is steeped in cold water for 12–24 hours, which extracts the coffee's natural sweetness while leaving behind most of the harsh acids and bitter compounds.
The result? A concentrate that's naturally smooth, slightly chocolatey, and easy on the stomach — even for people who normally find coffee too acidic. It also contains slightly more caffeine per millilitre than filter coffee, since you typically dilute the concentrate before drinking.
If you're curious how a well-insulated stainless steel cup keeps your coffee at the perfect temperature for hours, you'll love what it does for cold brew too — more on that in Step 4.
What You Need to Get Started
Cold brew requires almost no special gear. Here's what you need:
Coffee: Use coarsely ground beans — finer grinds cloud the liquid and make straining difficult. Any roast works, but medium to dark roasts give the richest, most chocolatey results. Aim for about 80–100 g of coffee per litre of water (a 1:10 to 1:12 ratio).
Water: Cold or room-temperature water. Filtered water gives a cleaner flavour, but tap water works fine.
A container: Any large jar, jug, or bottle with a lid. A 1-litre stainless steel bottle is ideal — it goes straight from the fridge to your bag without leaking a drop. The HEY SAHNI stainless steel bottle is double-walled and keeps cold brew cold all day.
Something to strain with: A fine-mesh sieve, a coffee filter, or a piece of muslin cloth. If you use a French press, you can press and strain in one step.
Step-by-Step: How to Make Cold Brew
Making cold brew is almost entirely hands-off. Here's the full process:
1. Grind your coffee coarsely. If you're buying pre-ground, look for "French press" or "cold brew" grind size. You want chunky grounds, not fine powder.
2. Combine coffee and water. Add 80–100 g of grounds to a large jar or French press. Pour over 1 litre of cold water. Stir gently to make sure all the grounds are wet.
3. Steep in the fridge for 12–24 hours. Cover and refrigerate. 12 hours gives a lighter, more delicate result; 24 hours produces a stronger, more concentrated brew. Don't steep at room temperature — fridge-steeping is slower and produces a cleaner flavour.
4. Strain. Pour the cold brew through a fine-mesh sieve lined with a coffee filter (or press your French press plunger and pour). Don't squeeze or press the grounds — it releases bitterness.
5. Dilute and enjoy. Cold brew concentrate is strong. Start with a 1:1 ratio of concentrate to water, milk, or oat milk. Adjust to taste. Serve over ice or straight from the fridge. For the best iced coffee on the go, pour it straight into your stainless steel bottle and head out.
How to Store Cold Brew (And How Long It Keeps)
Undiluted cold brew concentrate keeps for up to 2 weeks in the fridge. Once you've diluted it with milk or water, drink it within 2–3 days.
The key is an airtight container. Glass works well, but a stainless steel bottle is even better — it's completely sealed, doesn't absorb odours, and goes with you wherever you go. The HEY SAHNI stainless steel bottle keeps cold brew cold for up to 24 hours thanks to its double-wall vacuum insulation, so you can batch-brew on Sunday and enjoy fresh cold brew all week.
One tip: store the concentrate undiluted. It takes up less space and stays fresh longer. Just dilute your glass when you're ready to drink. If you're wondering whether stainless steel is safe for drinks, the short answer is yes — food-grade 18/8 stainless steel is non-reactive and won't affect the flavour of your cold brew.
Cold Brew Variations to Try
Once you've made your first batch, it's easy to experiment:
Cold Brew Tonic: Fill a glass with ice and tonic water, then pour cold brew concentrate over the top. The bitterness of the tonic and the sweetness of the cold brew balance each other perfectly.
Cold Brew Latte: Mix concentrate 1:1 with oat milk or whole milk. Add a dash of vanilla syrup if you like it a little sweet.
Cold Brew with Cinnamon: Add a cinnamon stick to the grounds before steeping. The result is warm and spiced — surprisingly good even served ice cold.
Mint Cold Brew: Add a handful of fresh mint leaves to the jar before steeping. Light, refreshing, and ideal for summer.
If you enjoy experimenting with coffee drinks at home, our guide to making matcha hot and iced is worth a read too — the same bottle works perfectly for both.
FAQ
Can I make cold brew without special equipment?
Yes. All you need is a large jar, coarsely ground coffee, cold water, and something to strain it — a sieve with a coffee filter works perfectly. No cold brew maker required.
How long does cold brew last in the fridge?
Undiluted cold brew concentrate stays fresh for up to 2 weeks in a sealed container in the fridge. Once diluted with milk or water, drink it within 2–3 days.
How much caffeine does cold brew have?
Cold brew concentrate contains more caffeine per millilitre than filter coffee, because it uses a higher coffee-to-water ratio. Once diluted 1:1, a 250 ml glass of cold brew has roughly the same caffeine as a double espresso — about 120–200 mg depending on the bean.
Can I make cold brew in a stainless steel bottle?
Yes. A wide-mouth stainless steel bottle is perfect for cold brewing. Add your grounds and water, seal the lid, steep in the fridge, then strain through a coffee filter. The bottle then doubles as your storage and serving vessel.
Why is my cold brew bitter?
Bitterness usually comes from over-steeping (more than 24 hours), too fine a grind, or squeezing the grounds while straining. Steep for 12–20 hours, use a coarse grind, and strain gently.
Is cold brew stronger than espresso?
As a concentrate, yes — cold brew has a higher caffeine concentration. But once diluted for drinking, a typical serving is closer to a long black or double espresso in strength.
The Author: Svenja Müller
Svenja is the Social Media Manager at HEY SAHNI and helps share the brand's story, community and coffee culture online. Living on Mallorca and working closely with the brand, she has developed a deep appreciation for great coffee, meaningful rituals and the culture behind every cup.