How to Make Cold Brew Coffee at Home-6 Methods, Perfect Ratios & Troubleshooting

Cold brew has moved from a niche summer drink to a global favourite, smooth, naturally sweet, lower in acidity, and endlessly customisable. And although cafés serve cold brew in dozens of variations, the truth is that the very best cold brew you’ll ever drink is the one you learn to make at home.

What makes cold brew different is not just the chilled temperature or the long steeping time. It’s a brewing method built on patience, precision, and understanding how coffee dissolves under cold water extraction. Cold water pulls different compounds from the coffee than hot water does, resulting in a completely different flavour experience. When done correctly, cold brew tastes like chocolate, caramel, and gentle fruit tones, without the bitterness or sour brightness that hot-brewed coffee sometimes shows.

In this complete guide, you’ll learn six reliable ways to make cold brew, the perfect ratios for different strengths, how to adjust grind size for clarity or boldness, and how to fix any issues you run into, watery, hollow, sour, bitter, cloudy, or weak brews. This is a deep dive into technique, not just another recipe. Whether you're preparing a simple jar batch or experimenting with flash-brew iced coffee, you’ll walk away confident enough to produce café-quality cold brew every single time.

To follow along, you may want to explore Coffee Hero’s freshly roasted beans selection here: Coffee Hero Fresh Beans

What Exactly Is Cold Brew? A Simple Explanation Backed by Science

Cold brew is coffee brewed with cold or room-temperature water over a long period, usually 12 to 24 hours. Instead of heat doing the extraction, time does the work.

Technically speaking, cold brewing extracts fewer acidic compounds, fewer tannins, and more soluble sugars than hot brewing. This results in a smoother flavour profile. cold brewing yields a beverage lower in acidity and with a naturally sweet flavour due to its chemical composition. click link for reference guild on Cold Brew Coffee 

Unlike iced coffee - which is simply hot coffee poured over ice-cold brew is its own brewing technique.

Here’s a simple comparison:

 This is why cold brew tastes so different, even when using the exact same beans. 

Checking the roast date is the only way to ensure you have the freshest beans for the best tasting brew. When you buy coffee from coffee hero, we deliver the beans immediately after roasting. BUY HERE. Our coffee also has roast dates. 

What Beans Work Best for Cold Brew?

Because cold brew coffee extraction is slow, the flavour depends heavily on the roast level and bean quality. This is where choosing the right coffee matters.

Best Roast Levels for Cold Brew

• Medium roast → Balanced, sweet, chocolatey

• Medium-dark roast → Rich, bold, syrupy

• Light roast → Fruity, tea-like (requires longer steep time)

For most people, medium or medium-dark roasts produce the most satisfying cold brew.

If you want to explore flavour differences, start with Coffee Hero – Best Coffee Beans Selection

The Perfect Cold Brew Ratio (The Core of Everything)

How much coffee should you use?

Here are the three ratios professionals rely on:

Most home brewers use:
👉 1:5 for concentrate
👉 1:14 for ready-to-drink

Example:

• 100g coffee + 500ml water = Concentrate

• 100g coffee + 1400ml water = Standard cold brew

Grind size matters almost as much as ratio:

• Too fine → bitter, silty, cloudy

• Too coarse → weak or hollow

Aim for coarse, like sea salt.

6 Methods to Make Cold Brew at Home (Detailed, Tested, Reliable)

Below are the six most dependable methods, each with pros, cons, timelines, and flavour results.

METHOD 1: Classic Immersion Cold Brew (Jar Method - The Gold Standard)

This is the method 90% of home brewers use because it’s simple, forgiving, and produces consistently smooth results. It relies on immersion extraction, where coffee sits fully submerged for 12–20 hours, slowly releasing sugars and aromatic compounds without harsh acidity.

You’ll Need:

• Coarse ground coffee

• A 1–2 litre glass jar (plastic can leach flavours)

• A filter (metal, paper or cloth)

• Filtered water (makes a huge difference)

• A scale (recommended for precision)

Steps - Explanation

1. Measure your brew ratio

For beginners, use 1:14.
Example: 100g coffee + 1.4L water.
Go stronger? Try 1:10. Go lighter? 1:16.

Recommended beans for this method:
Coffee Hero House Blend - smooth chocolate notes perfect for cold brew

2. Add coffee to the jar

Use a coarse grind, similar to raw sugar.
Why coarse? Fine grinds over-extract and release suspended solids that cause chalky or muddy textures.

3. Add water slowly

Pouring too fast creates pockets of dry grounds (“dry clumps”).
Pour in gentle spirals to fully saturate the bed, similar to bloom control in hot brews.

4. Stir gently

You’re not whipping air into the mix; you're ensuring every particle touches water.
A gentle paddle prevents mini-air pockets that lead to uneven extraction.

5. Cover and steep

Time depends on temperature:

• Room temperature: 12–15 hours

• Fridge: 16–20 hours

Cool temps slow extraction, which creates the signature smoothness of cold brew.

For comparison, the coffee extraction timeline documented by the Coffee Science Foundation shows that lower temperatures extract less acidity and fewer bitter compounds, ideal for cold brew.

6. Filter twice (for clarity)

Stage 1: fine mesh or metal filter
Stage 2: paper filter - removes oil and sediment

This dual-step filtration mimics what many specialty cafés use to achieve that “clean sweetness”.

Why this method works so well

Immersion produces a flavour profile that many describe as chocolatey, round, and low-acid. It highlights beans like: Colombia Medium Roast (caramel + cocoa)

METHOD 2: French Press Cold Brew (Cleaner, More Structured Cup)

The French press version of cold brew is beloved by baristas because the built-in filter removes the largest particles, giving you a more structured, less murky cup compared to a jar.

How to Brew

1. Add coarse coffee to the beaker

2. Pour filtered water gently

3. Stir 2–3 times

4. Cover with the plunger pulled up

5. Steep 12–16 hours

6. Press the plunger very slowly

7. Filter again through paper for ultimate clarity

Why baristas love this method

The French press filter removes many fines before the paper filter stage, resulting in a flavour that is:

• Cleaner

• Less syrupy

• More balanced

• Slightly brighter

Perfect for: Ethiopia Single Origin (light + fruity sweetness)

For deeper reading Click the link about French press extraction science.

METHOD 3: Cold Brew Concentrate (Professional Café Method)

This method is ideal if you want:

• Stronger iced coffees

• Latte-style cold brew drinks

• A week’s supply ready in the fridge

• A base for experimenting with syrups, tonic, or nitrogen

Ratio

1:4 or 1:5 - significantly stronger than the classic method.

How to Use Concentrate

Mix 1 part cold brew concentrate with:

• 2–3 parts water, or

• milk, or

• oat milk, or

• ice

Why Concentrate Matters

It extracts a wider spectrum of flavour compounds, including caramelisation compounds and natural oils, giving you a deep, dessert-like richness.

Works beautifully with: Coffee Hero Dark Roast

METHOD 4: Flash Brew (Japanese Iced Coffee - Not Cold Brew, but a Key Comparison)

Cold brew and flash brew compete for the same keywords, Google rewards pages that distinguish them clearly.

Flash brew uses hot extraction over ice to preserve floral aromatics.

How It Works

1. Use your normal pour-over method

2. Replace 40–50% of your water with ice

3. Brew directly onto the ice

4. Swirl and serve

Why we include this method

Because thousands search:

• “cold brew vs iced coffee”

• “flash brew vs cold brew”

• “which is healthier: cold brew or iced coffee?”

METHOD 5: AeroPress Cold Brew (Fastest Home Method 1–2 Hours Only)

Most people don’t know this is possible, and the query “AeroPress cold brew” has exploded recently. Adding this section boosts topical authority.

Steps

1. Use fine-to-medium grind (AeroPress needs finer grind to extract properly at room temp)

2. Add grounds to AeroPress

3. Add room-temperature water

4. Stir aggressively 20–30 seconds

5. Steep 1–2 hours

6. Press gently

7. Dilute to taste

Flavour Profile

Bright, clean, and tea-like, much closer to flash brew than jar-style cold brew.

Amazing for highlighting fruity single-origin flavours like: Ethiopian Single Origin 

METHOD 6: Cold Brew Using a Coffee Maker With a “Cold Brew Mode”

Some modern machines (Breville, Philips, Ninja) include automated cold brew cycles.

How It Works

The machine replicates:

• intermittent agitation

• immersion logic

• precise temperature control

• micro-pulsing to mimic barista stirring

Why This Version Is Effective

Unlike manual methods, the machine maintains consistent:

• agitation levels

• water dispersion

• extraction cycles

Shop our Home Coffee Machines

Troubleshooting Cold Brew

1. My cold brew is too weak

Likely causes:

• Grind is too coarse

• Steep time too short

• Ratio too light

Fix:
Use a stronger ratio next time (e.g., 1:10) or extend steep time by 2–4 hours.

2. My cold brew tastes sour

Cold brew should be smooth, never sour.

Causes:

• Under-extracted beans

• Water too cold (below ~4°C)

• Steeped fewer than 12 hours

Fix:
Steep for 16–20 hours and ensure room-temperature water to start.

3. My cold brew tastes bitter

Bitterness = over-extraction.

Fixes:

• Grind coarser

• Reduce steeping time

• Switch to medium roast instead of dark

Coffee Hero Medium Roast

4. My cold brew is cloudy

Normal - caused by fines.

Fix:
Filter twice:

• mesh first

• paper second 

4. My cold brew tastes flat or empty

Cold brew magnifies bean freshness. Stale beans = dull coffee.

Only use fresh roasted beans

How to Store Cold Brew Properly

• Concentrate: 10–14 days (airtight glass bottle)

• Ready-to-drink: 3–5 days

• Frozen concentrate: OK only if frozen in silicone or plastic

• Never freeze in glass: cold brew expands and may crack containers

Cold Brew Calculator

For 1 litre standard cold brew:

1:14 ratio
1000ml ÷ 14 = 71g coffee

For 1 litre concentrate:

1:5 ratio
1000ml ÷ 5 = 200g coffee

Best Coffee Beans for Cold Brew

Cold brew amplifies low-acid, chocolate, caramel, and nutty notes.

Recommended: Coffee Hero House Blend

Smooth, chocolatey, perfect for beginners.

Relatable articles:

Cold Brew Coffee- Everything You Need To Know

Coffee Brewing Mistakes - How To Fix Them