Make a coarse-ground cold-brew concentrate, steep it in the refrigerator for 16--24 hours, strain it well, and store it sealed and chilled. Build drinks one glass at a time, starting with equal parts concentrate and cold water, milk, or plant milk over plenty of ice instead of diluting the entire batch in advance.
Make the Week's Cold-Brew Concentrate
Cold brew is especially useful for a make-ahead iced-coffee routine because the coffee is steeped in cold water rather than brewed hot and cooled over ice. This batch makes a strong base designed to be diluted when you serve it.
Cold-Brew Concentrate Batch
Ingredients
- 85 g coarse- or extra-coarse-ground coffee, about 1 cup grounds
- 480 ml cold filtered water, about 2 cups
This is a 1:4 coffee-to-water ratio by weight: a dependable starting point for a concentrate that can be adjusted per glass.
Method
- Combine the coffee and water. Add the coarse grounds to a jar or other covered container. Pour in the cold filtered water and stir gently until all the grounds are saturated.
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Cover and refrigerate. Steep the mixture in the refrigerator for 16--24 hours.
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Strain the coffee. Pour the steeped coffee through a lined fine-mesh strainer as described below.
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Transfer and label. Move the strained concentrate to an airtight container, label it with the brew date, and refrigerate it promptly.
Use a coarse or extra-coarse grind rather than a drip-coffee grind. The grounds should look more like coarse cornmeal or raw sugar than fine powder. A coarse grind is easier to filter and helps avoid a harsh, sediment-heavy batch. For another home cold-brew method using coarse grounds and a strong concentrate, see this cold brew coffee recipe.
Strain Cleanly for a Smoother Concentrate
Set a fine-mesh strainer over a bowl or measuring jug and line it with cheesecloth or paper coffee filters. Pour in the steeped coffee and let gravity do the work.
Do not rush the process by squeezing, stirring aggressively, or pressing the wet grounds. Pressing can push fine particles through the filter and is one of the common causes of a bitter or harsh-tasting concentrate.
Avoid These Common Problems
- Bitter or harsh coffee: The grounds may have been too fine, the steep too long, or the grounds may have been pressed during straining. Use a coarser grind next time and stay closer to the lower end of the 16--24-hour steeping window.
- Concentrate tastes too strong: Dilute it with more water or milk in the glass. Concentrate is meant to be adjusted, not treated as a ready-to-drink coffee.
Build Iced Drinks by the Glass
Keep the stored batch plain. Add water, milk, plant milk, sweetener, and other mixers only when you make a drink. Equal parts concentrate and cold liquid is a useful starting point, but it is not a fixed rule: add more mixer for a lighter drink or less for a stronger one.
Fill each glass generously with ice before adding the coffee. That gives you a cold drink from the first sip and leaves room for dilution without a weak finish.
| Drink | Concentrate | Mixer and Finish |
|---|---|---|
| Black Iced Coffee | ½ cup | ½ cup cold water; serve over ice |
| Iced Latte | ½ cup | ½ cup cold milk or oat milk; serve over ice |
Black Iced Coffee
Fill a tall glass with ice. Add ½ cup concentrate and ½ cup cold water. Stir and taste. For a stronger glass, reduce the water slightly; for a lighter one, add more.
Iced Latte
Fill a glass with ice. Add ½ cup concentrate and ½ cup cold milk or oat milk. Stir until chilled. This is the simplest way to turn the batch into a creamy iced latte without putting milk into the stored concentrate.
Sweet Iced Coffee
Start with either the black iced coffee or iced latte formula. Add your preferred sweetener to taste, then stir well. Sweeten individual drinks rather than the full batch so you can keep some servings unsweetened and vary the flavor through the week.
One iced-coffee formula uses ½ cup cold-brew coffee, ½ cup cold water, ¼ cup milk or cream, ice, and optional sweetener. That version makes a milk-containing iced coffee rather than a black coffee; use it as a richer variation when you want it.
Coffee Tonic (Unverified)
No approved evidence supports a tonic water variation for cold brew concentrate. If you choose to experiment, treat it as a single-serving drink and do not rely on the storage guidance provided for plain concentrate.
Store the Plain Concentrate for the Week
For a batch intended to last through several iced drinks, store only the strained, plain concentrate.
- Use a clean airtight container.
- Refrigerate the concentrate at 35--40°F.
- Label the container with the brew date.
- Keep it chilled between servings.
- Plan to use it within about one week.
About one week is practical refrigerated guidance, not a universal safety guarantee. Storage conditions, container cleanliness, refrigerator temperature, and handling all matter. Keeping the concentrate undiluted until serving is also more practical than storing a ready-to-drink batch with water, milk, or other additions.
Do not assume that a prepared iced latte, sweetened drink, or diluted coffee has the same storage window as plain concentrate. Make milk- and plant-milk-based drinks by the glass, and refrigerate any unused ingredients separately.
When to Discard It
Discard the concentrate if you notice:
- Visible mold or fuzzy floating particles
- A sour, fermented, or otherwise clearly off odor
- Unusual cloudiness that does not look like ordinary settled sediment
- Other distinctly off sensory changes
A small amount of fine coffee sediment can be normal, especially after refrigeration. Mold, abnormal cloudiness, or an off smell are different: do not taste the batch to test it.
Label your fresh concentrate, refrigerate it, and make your first glass today---whether that is a simple black iced coffee, an iced latte, or a sweetened version.
