Making A Single Serving Of Cold Brew Coffee

Quick answer

• Use a coarse grind for your coffee.
• Aim for a 1:4 to 1:8 coffee-to-water ratio.
• Steep for 12-24 hours, depending on your preference.
• Filter thoroughly to remove sediment.
• Dilute the concentrate with water or milk to taste.
• Store in the fridge for up to a week.

Who this is for

• The solo coffee drinker who wants a smooth, less acidic brew.
• Anyone who enjoys iced coffee but finds regular brewed coffee too bitter when chilled.
• People looking for a make-ahead coffee solution for busy mornings.

What to check first

Brewer type and filter type

Cold brew is pretty forgiving, but the right setup helps. You can use a French press, a mason jar with a fine-mesh strainer, or a dedicated cold brew maker. The key is a good filter. Paper filters can work, but they can slow things down and might clog. A fine-mesh metal strainer or a cloth filter is usually better for cold brew concentrate.

A French press is a versatile option for making cold brew, allowing for easy steeping and filtering. You can find excellent French presses on Amazon to get started.

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• Wash in warm, soapy water before first use and dry thoroughly
• Not for stovetop use
• Turn lid to close spout
• Easy-to-clean glass carafe

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Water quality and temperature

Tap water is fine for most folks, but if yours tastes funky, your cold brew will too. Filtered water is always a safe bet. You’ll be using cold or room-temperature water for steeping, so no need to worry about heating it up. That’s the beauty of cold brew.

Grind size and coffee freshness

This is crucial. You want a coarse grind, like breadcrumbs or even coarser. Too fine a grind will lead to a muddy, over-extracted mess that’s hard to filter. Freshly roasted beans make a difference, but even pre-ground coffee will work if you grind it coarse enough. Just try to use it within a few weeks of the roast date.

Coffee-to-water ratio

This is where you control the strength. For a single serving, you’re making a concentrate. A good starting point is 1:4 (coffee to water by weight), meaning 1 oz of coffee to 4 oz of water. Some go as strong as 1:2 or as mild as 1:8. Experiment to find your sweet spot.

Cleanliness/descale status

Make sure your brewing vessel and any filters are squeaky clean. Old coffee oils can turn rancid and ruin your brew. If you’re using a machine with heating elements (though not typical for cold brew), check its descaling status.

Step-by-step (brew workflow)

1. Measure your coffee. For a single serving, let’s say you’re aiming for about 8 oz of finished drink. Start with 1 oz of coarsely ground coffee.

• What good looks like: Precisely measured grounds, ready for steeping.
• Common mistake: Guessing the amount. This leads to inconsistent strength. Use a scale if you can.

For consistent results, especially when making a single serving, using a coffee scale is highly recommended. It takes the guesswork out of measuring your grounds and water.

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2. Add coffee to your brewing vessel. Put the grounds into your French press, mason jar, or cold brew maker.

• What good looks like: All the grounds are in the vessel, ready for water.
• Common mistake: Spilling grounds outside the vessel. Clean up any stray grounds.

3. Add cold or room-temperature water. Pour in your measured water. For 1 oz of coffee, start with 4 oz of water.

• What good looks like: The water is evenly distributed, saturating all the coffee grounds.
• Common mistake: Pouring too fast, which can cause grounds to clump. Pour slowly in a circular motion.

4. Stir gently. Give the mixture a quick, gentle stir to ensure all the coffee is wet.

• What good looks like: No dry clumps of coffee visible.
• Common mistake: Over-stirring. This can agitate the grounds too much and lead to bitterness.

5. Cover and steep. Put a lid on your vessel or cover it tightly. Let it sit at room temperature or in the fridge.

• What good looks like: The vessel is sealed to prevent contamination and oxidation.
• Common mistake: Leaving it uncovered. This lets in unwanted smells and can affect the taste.

6. Wait it out. Steep for 12 to 24 hours. Shorter times yield a lighter brew; longer times give a stronger, bolder flavor.

• What good looks like: Patience. You’ve let the coffee and water do their magic.
• Common mistake: Impatience. Pulling it too early results in weak, watery coffee.

7. Begin filtering. If using a French press, slowly press the plunger down. If using a jar and strainer, pour through your chosen filter.

• What good looks like: A slow, steady stream of liquid coffee without excessive sediment.
• Common mistake: Pressing the plunger too hard or fast. This can force grounds through the filter.

8. Filter again if needed. You might want to pour the filtered liquid through a paper filter or cheesecloth for an extra-clean brew.

• What good looks like: Crystal-clear cold brew concentrate with minimal to no grit.
• Common mistake: Skipping this step if you notice sediment. More filtering equals a smoother drink.

9. Dilute to taste. Your cold brew concentrate is strong. Add water, milk, or your favorite creamer until it tastes right to you. A 1:1 ratio of concentrate to water is a good starting point.

• What good looks like: A perfectly balanced, refreshing coffee drink.
• Common mistake: Drinking the concentrate straight. It’s meant to be diluted!

10. Serve and enjoy. Pour over ice and savor your homemade single serving of cold brew.

• What good looks like: A delicious, smooth cup of coffee, just how you like it.
• Common mistake: Not serving it over ice. Cold brew is best enjoyed chilled.

Common mistakes (and what happens if you ignore them)

Decision rules (simple if/then)

• If your cold brew tastes weak, then increase the coffee-to-water ratio (use more coffee or less water) because a stronger ratio makes a more concentrated brew.
• If your cold brew tastes bitter, then shorten the steeping time or check your grind size because over-extraction or too fine a grind causes bitterness.
• If you have sediment in your final cup, then filter it again through a finer medium because this removes any remaining coffee particles.
• If your cold brew has an off-flavor, then check your water quality and equipment cleanliness because these are the most common culprits.
• If you want a bolder, more intense flavor, then steep for closer to 24 hours because longer steep times extract more flavor compounds.
• If you prefer a lighter, smoother cold brew, then steep for around 12 hours because this extracts less intensely.
• If your grounds are difficult to filter, then your grind is likely too fine, so use a coarser grind next time because fine grinds clog filters.
• If you’re making cold brew for the first time, then start with a 1:4 coffee-to-water ratio and 18 hours of steeping because this is a reliable starting point.
• If you want to speed up the brewing process slightly, then use slightly warmer (but still cold or room temp) water because this can help with extraction.
• If your cold brew tastes sour, then it might be under-extracted, so try steeping a bit longer or ensuring all grounds are saturated because sourness often indicates insufficient extraction.

FAQ

How long does single-serving cold brew last?

Your cold brew concentrate should last about a week when stored in an airtight container in the refrigerator. Always check for any off-smells before drinking.

Can I use pre-ground coffee?

Yes, but you absolutely need to make sure it’s ground very coarsely. If you can only find pre-ground coffee, look for one labeled for French press or cold brew if possible, or grind it yourself if you have a grinder.

What kind of coffee beans are best for cold brew?

Medium to dark roasts are popular because they tend to have lower acidity and richer, chocolatey or nutty notes that shine in cold brew. However, you can use any beans you enjoy.

Why is my cold brew cloudy?

Cloudiness usually means you have fine coffee particles in your brew. This is often caused by too fine a grind or not filtering thoroughly enough.

How much caffeine is in single-serving cold brew?

It varies a lot based on the coffee-to-water ratio and steep time, but cold brew concentrate is generally more caffeinated than drip coffee. Diluting it will reduce the caffeine per serving.

Do I have to use filtered water?

It’s not strictly necessary, but if your tap water has a strong taste or odor, it will carry over into your cold brew. Using filtered water will generally result in a cleaner, purer coffee flavor.

What’s the difference between cold brew concentrate and ready-to-drink cold brew?

Concentrate is a much stronger brew that needs to be diluted with water or milk before drinking. Ready-to-drink cold brew is already diluted to a drinkable strength.

Can I make hot coffee with cold brew concentrate?

You can, but it’s not ideal. Cold brew concentrate is designed to be diluted with cold liquid. Heating it might alter its smooth flavor profile.

What this page does NOT cover (and where to go next)

• Specific types of coffee beans and their flavor profiles.
• Advanced filtration techniques for ultra-clear cold brew.
• Recipes for cold brew-based coffee cocktails or other mixed drinks.
• The science behind caffeine extraction in cold brewing.
• How to scale up cold brew production for larger batches.