What You Need
Cold brew concentrate is the simplest coffee you can make. You need coffee, water, a container, something to filter with, and patience. The equipment ceiling is low — you can make excellent cold brew in a mason jar with a cheesecloth — but a dedicated cold brew maker (our cold brew maker guide covers the options) makes the weekly routine easier and more consistent.
| Item | Specification | Why It Matters |
|---|---|---|
| Coffee beans | Medium to dark roast preferred | Light roasts produce thin, sour cold brew |
| Grind size | Extra coarse (rock salt) | Prevents over-extraction and reduces sediment |
| Water | Filtered, room temperature or cold | Mineral content affects extraction; filtered is best |
| Ratio | 1:5 by weight (concentrate) | 100g coffee : 500g water is a good starting batch |
| Container | Glass or food-grade plastic | Glass is flavor-neutral; plastic absorbs oils over time |
| Filter | Fine mesh, felt, or paper | Finer filtration produces cleaner, smoother concentrate |
| Time | 14–18 hours in the fridge | Shorter is thin; longer risks bitterness |
The Method
Step 1: Grind and Measure
Weigh your coffee — 100 grams is a good starting batch, producing about 500ml of concentrate (enough for roughly a week of daily cold brew when diluted). Grind extra coarse — the coarsest setting on most grinders, similar to rock salt or raw sugar. If you don't have a grinder, many coffee shops will grind beans for cold brew on request. Freshness still matters: beans roasted within the past two to four weeks produce noticeably better cold brew than older stock.
Step 2: Combine and Steep
Add ground coffee to your brewing container. Pour 500 grams of filtered, room-temperature water over the grounds. Stir gently to ensure all grounds are saturated — dry pockets on top are the most common beginner mistake and produce under-extracted, uneven batches. Cover the container and place it in the refrigerator. Fridge-steeping (versus counter-steeping at room temperature) produces a noticeably cleaner, brighter concentrate with less risk of over-extraction.
Step 3: Filter
After 14 to 18 hours, filter the concentrate. The filtration method determines your cup clarity. A Toddy felt filter or paper filter through a pour-over dripper produces the cleanest, smoothest result. Fine mesh (like the filters in OXO and Hario cold brew makers) produces a slightly more full-bodied concentrate with minimal sediment. Cheesecloth works but lets through more fine particles. Double-filtering (mesh first, then paper) produces the absolute cleanest concentrate if you're particular about sediment.
Step 4: Store
Transfer filtered concentrate to a sealed glass container (mason jars work perfectly). Label with the date. Store in the refrigerator. The concentrate is now ready to use.
Diluting and Serving
Cold brew concentrate is intentionally too strong to drink straight. Dilution is where you customize the final cup to your preference. Standard dilution ratios as a starting point:
| Dilution | Concentrate : Water/Milk | Result |
|---|---|---|
| Strong iced coffee | 1:1 | Bold, concentrated, dark |
| Standard iced coffee | 1:2 | Balanced, smooth, approachable |
| Light iced coffee | 1:3 | Lighter, refreshing, low-intensity |
| Hot cold brew | 1:1 (hot water) | Smooth hot coffee, low acid |
| Cold brew latte | 1:1 to 1:2 (milk) | Creamy, sweet, cafe-style |
Ice dilution matters. If you're pouring concentrate over ice, start with a stronger ratio (1:1) because the melting ice will dilute further. If you're mixing with already-cold water, use the standard ratio. Experiment with your preferred strength — the beauty of concentrate is that you control the final cup every time.
Cold brew's low acidity and smooth profile make it an excellent base for flavored drinks. Vanilla, simple syrup, cinnamon, or chocolate pair naturally without the sharp edges that hot coffee sometimes creates. The concentrate format means you can make one batch and customize each serving differently throughout the week.
Storage and Shelf Life
Undiluted concentrate lasts 10 to 14 days in the fridge in a sealed glass container. After two weeks, oxidation noticeably degrades flavor — the coffee starts tasting flat and stale. Ready-to-drink diluted cold brew lasts 5 to 7 days before quality drops.
Glass containers are strongly preferred over plastic. Glass is completely flavor-neutral and doesn't absorb coffee oils. Plastic (even BPA-free Tritan) absorbs oils over repeated use, developing residual flavors that affect subsequent batches. Mason jars, swing-top glass bottles, or the glass carafes that ship with OXO and Toddy systems all work well.
Label every batch with the brew date. It's easy to lose track, and cold brew that's been in the fridge for three weeks tastes meaningfully worse than a one-week-old batch. A piece of masking tape and a marker is all you need.
Recommended Maker for Concentrate
While you can make cold brew concentrate in any container, a dedicated maker with purpose-built filtration produces consistently cleaner results with less effort. The Toddy Cold Brew System is specifically designed for concentrate brewing — its felt filter produces the smoothest, most sediment-free result of any home system, and the capacity handles the 100-gram batches this guide recommends.
Toddy Cold Brew System
Budget ($)Felt filter for the smoothest concentrate, 48 oz capacity — the system designed specifically for concentrate brewing.
A 100-gram batch produces roughly 500ml of concentrate. At a 1:2 dilution, that's about 1.5 liters of drinking cold brew — roughly five to six servings. For a two-person household drinking daily, double the batch to 200 grams of coffee and 1 liter of water. One batch per week, five minutes of active work, and your cold brew costs a fraction of coffee shop prices.
Cold brew concentrate is the highest-ROI coffee habit you can build. One hundred grams of coffee, five hundred grams of water, extra-coarse grind, 14 to 18 hours in the fridge, filter, store, dilute to taste. Five minutes of weekly setup replaces daily coffee shop trips. Use glass containers, label with the date, and consume within two weeks for peak quality.
Frequently Asked Questions
What ratio should I use for cold brew concentrate?
Use a 1:5 ratio of coffee to water by weight for concentrate. For example, 100 grams of coffee to 500 grams (500ml) of water. This produces a strong concentrate that you dilute before drinking, typically at a 1:1 or 1:2 ratio of concentrate to water or milk. If you want ready-to-drink strength, use a 1:8 ratio and skip the dilution step.
Can I use regular ground coffee for cold brew?
You can, but results will be worse. Pre-ground coffee is typically a medium grind designed for drip machines, which is too fine for cold brew. It will over-extract during the 12-to-24-hour steep, producing bitter, harsh concentrate. Coarse grind is essential. If you must use pre-ground, reduce steep time to 8 to 10 hours and expect more sediment.
Can I heat up cold brew concentrate?
Yes. Dilute concentrate with hot water instead of cold for a smooth hot coffee. Cold brew heated this way retains its low-acid, smooth character — it tastes different from hot-brewed coffee because the extraction chemistry is fundamentally different. Many people prefer heated cold brew during winter months.