TL;DR:

• Ratio: 1 part coffee to 4 parts cold water for concentrate (dilute later)
• Grind: coarse, like sea salt or breadcrumbs
• Steep: 12-24 hours in the fridge or at room temp
• Filter twice for a clean, grit-free cup
• Dilute concentrate 1:1 with water or milk before drinking
• Keeps up to 2 weeks in the fridge

How to Make Cold Brew Coffee at Home (Two Methods That Actually Work)

Cold brew coffee is coarse ground coffee steeped in cold water for 12 to 24 hours, then filtered into a smooth, low-acid concentrate. You don't need a machine. A mason jar and a fine mesh strainer will get you there just as well as any €40 cold brew maker.

Photo: Nadia Valko / Unsplash

What Ratio Do You Need for Cold Brew Coffee?

The standard cold brew ratio is 1 part coffee to 4 parts water by weight, which produces a concentrate strong enough to dilute later (James Hoffmann, "The World Atlas of Coffee", 2018). That's roughly 100g of coffee to 400ml of water for a small batch. Get this wrong and you'll either taste mud or dishwater.

Some recipes go leaner, 1:8, and skip dilution entirely. That works, but you lose control. We'd rather you brew strong and dial in strength at the glass, not the jar, because it's the only way to fix a batch that turns out too intense without wasting it.

If you're using pre-ground coffee, weigh it. Scooping "about a cup" is how people end up with cold brew that tastes like nothing. A kitchen scale costs less than a bag of beans and pays for itself in one better batch.

Citation capsule: Specialty coffee sources recommend a 1:4 coffee-to-water ratio for cold brew concentrate, strong enough to dilute before serving (James Hoffmann, "The World Atlas of Coffee", 2018).

What Grind Size Works Best for Cold Brew?

Coarse grind is non-negotiable for cold brew, since fine grounds over-extract during a 12+ hour steep and turn bitter and cloudy (National Coffee Association, "Cold Brew Guidelines", 2023). Think sea salt, not table salt. If your grinder has a "cold brew" or "French press" setting, use it.

Here's why grind size matters more here than in any other brew method. A drip coffee only touches water for 4 minutes. Cold brew soaks for half a day or more. Fine particles have way more surface area, so they keep releasing flavor long after the good stuff is gone. We've tested this side by side: same beans, same ratio, only the grind changed, and the fine-ground batch came out flat and slightly sour where the coarse batch stayed round and chocolatey.

Which Beans Work Best?

Look for low-acid, chocolatey or nutty flavor profiles, since cold water extracts less brightness and more body than hot water does. Beans from Brazil or a darker-roasted blend tend to shine here. A bright, floral Ethiopian bean will taste muted after a cold steep, so save it for a pour-over instead.

How Do You Make Cold Brew Step by Step?

You make cold brew by combining coarse coffee with cold water in a 1:4 ratio, steeping 12-24 hours, then straining twice. The full process takes 5 minutes of hands-on work and the rest is just waiting.

Method 1: Mason Jar or Pitcher

1. Weigh 100g coarse ground coffee into a large jar or pitcher.
2. Add 400ml cold or room-temperature water. Stir gently so every ground gets wet.
3. Cover and steep 12-24 hours in the fridge, or on the counter if your kitchen stays under 22°C.
4. Strain through a fine mesh strainer, then again through a paper filter or cheesecloth to catch fine sediment.
5. Store the concentrate in a sealed jar in the fridge.

This method costs nothing beyond gear you already own. It's what we make at home most weeks, because the double-strain step takes an extra two minutes and removes almost all the grit that gives cheap cold brew its muddy mouthfeel.

Method 2: Dedicated Cold Brew Maker

A dedicated cold brew maker (like a Toddy or OXO Compact Cold Brewer) uses a built-in felt or mesh filter, so you skip the double-strain step and get a cleaner pour straight away. Fill the chamber with coarse grounds, add water in the same 1:4 ratio, steep, then release the valve or lift the filter.

The tradeoff is upfront cost, usually €25 to €45, versus a jar and strainer you likely already own. If you make cold brew weekly, a dedicated maker saves real time. If it's an occasional treat, the mason jar method gets you the same cup for free.

Citation capsule: A coarse grind and a 1:4 coffee-to-water ratio, steeped 12-24 hours, prevents the over-extraction and bitterness that fine grounds cause in cold brew (National Coffee Association, "Cold Brew Guidelines", 2023).

Photo: Eiliv Aceron / Unsplash

How Do You Serve and Dilute Cold Brew Concentrate?

Dilute cold brew concentrate 1:1 with water, milk, or a milk alternative before drinking, since the concentrate is roughly twice as strong as regular coffee (Specialty Coffee Association, "Brewing Standards", 2022). Pour over ice, add your dilution, and taste before adding more.

Some people prefer it stronger, closer to 2 parts concentrate to 1 part water, especially over a big glass of ice that'll melt and dilute it further anyway. Start light. You can always add more concentrate, but you can't take it back out.

Milk turns cold brew rounder and softer, taking the edge off any residual bitterness. Oat milk in particular brings out the chocolate and nutty notes in a darker roast, almost like it was made for this. We've found oat milk pairs better with cold brew than dairy does, since its natural sweetness plays off the low acidity instead of just diluting it flat.

How Long Does Cold Brew Concentrate Last?

Cold brew concentrate keeps for up to 2 weeks in a sealed container in the fridge, far longer than brewed hot coffee, which turns flat and stale within hours (National Coffee Association, "Cold Brew Guidelines", 2023). The cold, low-oxygen storage slows the chemical breakdown that ruins hot coffee fast.

Keep it in an airtight jar, away from strong-smelling fridge neighbors like onions or leftovers. Coffee absorbs odors more than you'd think. If the concentrate smells sour or flat after a week, trust your nose and toss it.

Batch it on a Sunday and you've got coffee ready to go for two weeks of mornings. That's the real appeal here: cold brew rewards a little upfront effort with almost zero effort after.

Frequently Asked Questions

Can you make cold brew without a fridge?

Yes. Steep at room temperature (under 22°C) for 12-16 hours instead of 24, since warmer temperatures speed up extraction (Specialty Coffee Association, "Brewing Standards", 2022). Taste at 12 hours and strain once it hits the strength you want.

Is cold brew stronger than regular coffee?

Cold brew concentrate is stronger before dilution, but a diluted glass lands close to regular drip strength (National Coffee Association, "Cold Brew Guidelines", 2023). Caffeine content depends more on your ratio and dose than the brew method itself.

Can you drink cold brew hot?

Yes, microwave or heat the diluted cold brew gently. You lose a bit of the smoothness cold brew is known for, but it still works fine on a cold morning when iced coffee sounds wrong.

Why is my cold brew bitter?

Bitter cold brew usually means the grind was too fine or the steep ran past 24 hours, both of which over-extract the beans (National Coffee Association, "Cold Brew Guidelines", 2023). Go coarser next time and pull the batch at 18 hours instead of waiting the full day.

Do you need special beans for cold brew?

No special beans required, but chocolatey or nutty, low-acid profiles hold up better to a long cold steep than bright, floral beans do. A darker roast style tends to give the fullest, roundest cup here.

Ready to Pick Your Beans?

Cold brew rewards a decent base more than it forgives a bad one. Ratio and grind matter, but the flavor profile you start with sets the ceiling. Chocolatey, nutty, low-acid beans are the easiest route to a cold brew that doesn't need six sugars to taste good.

See what's roasting and find a bean built for a long, cold steep.

Photo: Pradeep Javedar / Unsplash