old brew has a reputation for being a café thing — something that takes specialist equipment, precise technique, and more patience than most people can muster before their morning coffee. None of that is true.
Cold brew is one of the simplest things you can make at home, and one of the most rewarding. It produces a naturally smooth, low-acidity concentrate that keeps in the fridge for up to two weeks, ready to pour over ice whenever you need it. No boiling water, no specialist pouring technique, no timing to the second. Just coffee, cold water, and time.
Here's everything you need to know to make excellent cold brew at home from scratch.
What Is Cold Brew Coffee?
Cold brew is made by steeping coarsely ground coffee in cold or room-temperature water for an extended period — typically 12 to 24 hours — then filtering out the grounds. Because no heat is involved, the extraction chemistry is fundamentally different from hot brewing.
Hot water dissolves coffee compounds quickly and aggressively, including many of the acids and bitter elements that give hot coffee its characteristic sharpness. Cold water extracts much more slowly and selectively, drawing out sweetness and body while leaving behind many of the harsher compounds. The result is a concentrate that's naturally smooth, lower in acidity, and noticeably sweeter than the same beans brewed hot — even before you add anything to it.
It also keeps exceptionally well. A well-made batch of cold brew concentrate, stored in a sealed container in the fridge, stays fresh for up to two weeks. That's a fortnight of great cold coffee from a single batch that takes about 10 minutes of active effort to prepare.
What You'll Need
You don't need much to make cold brew at home. The essentials are:
Coffee — freshly ground is significantly better than pre-ground. Use a coarse grind, similar to what you'd use for a French press. Medium to dark roasts tend to work particularly well for cold brew — their natural sweetness and body translate beautifully into the concentrate. Single origin light roasts can be interesting, but the lower acidity extraction of cold brewing can sometimes leave them tasting flat.
Cold or room-temperature water — filtered water is worth using if your tap water is hard or heavily chlorinated, as it will make up the majority of your finished drink.
A vessel to brew in — at its simplest, any large jar or container will do. A dedicated cold brew maker makes the process significantly tidier and easier to repeat consistently.
A way to filter the grounds — a fine mesh strainer lined with a paper filter works in a pinch. Again, a dedicated system handles this for you cleanly and without mess.
The Right Ratio: Coffee to Water
Cold brew is typically made as a concentrate, then diluted before drinking. The standard starting ratio for concentrate is 1:4 to 1:5 coffee to water by weight — so 100g of coffee to 400–500ml of water. This produces a rich, strong concentrate that you dilute roughly 1:1 with cold water or milk before serving.
If you prefer ready-to-drink cold brew — full strength, straight from the fridge — use a ratio of around 1:8. This is more coffee-efficient and less flexible (you can't easily adjust strength at serving time), but it suits people who want to pour and go without thinking about dilution.
As a practical starting point for a home batch: 100g of coarsely ground coffee to 500ml of cold water makes a good concentrate for two to three days of regular drinking when diluted 1:1. Scale up or down as needed.
Step-by-Step: How to Make Cold Brew at Home
Step 1: Grind your coffee coarsely. Aim for a grind similar to rough sea salt or coarse sugar — noticeably coarser than you'd use for a V60 or AeroPress. A fine or medium grind will over-extract during the long steep time and produce a bitter, muddy result. If you're using a burr grinder, set it to its coarser end.
Step 2: Combine coffee and cold water. Add the ground coffee to your brewing vessel and pour over cold or room-temperature water. Give it a brief stir to make sure all the grounds are fully saturated — dry pockets of coffee won't extract properly.
Step 3: Cover and steep. Cover the vessel to prevent the coffee from absorbing fridge odours and place it in the fridge. Steep for 12–18 hours for a balanced, smooth concentrate. If you prefer a stronger, more intense result, steep for up to 24 hours. Steeping at room temperature rather than in the fridge speeds up extraction — 12 hours at room temperature produces a similar result to 18–20 hours in the fridge, though fridge steeping gives you more control and consistency.
Step 4: Filter. Once steeping is complete, filter out the grounds. If you're using a dedicated cold brew maker like the Toddy Home System, simply remove the stopper and let the concentrate drain through the built-in filter into the glass decanter below — it takes a few minutes and requires no intervention. If you're improvising, pour through a fine mesh strainer lined with a paper filter into a jug or jar. This takes longer but works well.
Step 5: Store and serve. Transfer the filtered concentrate to a sealed container and keep it in the fridge. It will stay fresh for up to two weeks. To serve, pour over plenty of ice and dilute with cold water or milk to taste — a 1:1 ratio of concentrate to water is a solid starting point, adjusting to preference.
The Easiest Way: Using a Dedicated Cold Brew Maker
Making cold brew in a jar works, but a dedicated system removes the mess and guesswork from the filtering stage — which is where most improvised setups run into trouble.
The Toddy Home Cold Brew System is the most popular home cold brew maker we stock, and for good reason. Toddy invented cold brew coffee in 1964 and their system is elegantly simple — a brewing container with a built-in felt filter system that drains the finished concentrate cleanly into a glass decanter. The decanter seals for fridge storage and pours neatly. There's no straining, no mess, and no wasted coffee stuck in a filter. It makes up to 1.1 litres of concentrate per batch, enough for a week or more of regular drinking.
If you want a smaller, more portable option — or you want to take cold brew on holiday or to the office — the Toddy Go Brewer is a compact cold brew maker that brews and stores in one vessel. Simple, practical, and currently discounted.
For something more involved, the Bruer Cold Drip Coffee Maker uses a slow drip method rather than immersion — cold water drips through the grounds over several hours, producing a brighter, more complex cup than immersion cold brew. It's a slower process with a distinctly different character, worth exploring once you've got the basics of immersion cold brew down.
Tips for Better Cold Brew
Use freshly ground coffee. Cold brew extracts slowly, so starting with stale pre-ground coffee amplifies every flaw in the beans. Grinding fresh immediately before brewing makes a noticeable difference to the sweetness and clarity of the finished concentrate.
Don't rush the steep. It's tempting to check on it after a few hours. Resist. Under-steeped cold brew tastes sour and weak — the long steep time is what produces the characteristic smoothness. Twelve hours is the minimum worth trying.
Experiment with roast level. Medium roasts — chocolatey, nutty, full-bodied — are the classic cold brew choice. But a natural-processed light roast can produce a cold brew that's almost fruit-juice sweet when done well. It's worth trying a few different beans once you have the method down.
Dilute to taste, not to a fixed ratio. The 1:1 dilution is a starting point, not a rule. Some people prefer their cold brew stronger; others like it longer and lighter over a full glass of ice. The concentrate format gives you full control at serving time.
Replace your filters regularly. If you're using a Toddy system, the felt filters do most of the heavy lifting and need replacing periodically. Toddy Felt Filter Packs and Toddy Paper Filter Bags are both available — paper filters produce a slightly cleaner, clearer concentrate if that's your preference.
Ready to get started? Browse our full cold brew collection — from the Toddy Home System to portable options and replacement filters.
Frequently Asked Questions
How long does cold brew take to make?
Most cold brew recipes call for a steep time of 12 to 24 hours. Steeping in the fridge for 18 hours is a reliable all-purpose starting point that produces a smooth, balanced concentrate. Steeping at room temperature is faster — 12 hours at room temperature produces a similar strength to 18–20 hours in the fridge — but fridge steeping gives you more control and reduces the risk of over-extraction. Once filtered, cold brew concentrate keeps in the fridge for up to two weeks.
What is the best coffee-to-water ratio for cold brew?
For cold brew concentrate — the most common home approach — a ratio of 1:4 to 1:5 coffee to water by weight is the standard starting point. Use 100g of coarsely ground coffee to 400–500ml of cold water, then dilute the finished concentrate 1:1 with water or milk before serving. For ready-to-drink cold brew at full strength, use a ratio of around 1:8. Adjust based on taste — if your concentrate is too strong, use less coffee or more water next time; if it's weak, do the opposite.
What grind size should I use for cold brew?
Cold brew requires a coarse grind — similar in texture to rough sea salt or the grind you'd use for a French press. A fine or medium grind over-extracts during the extended steep time, producing a bitter, muddy, sometimes harsh result. A coarse grind extracts slowly and evenly, giving you the smooth, sweet concentrate cold brew is known for. Any burr grinder set to its coarser settings will give good results. Pre-ground coffee intended for filter or espresso is too fine for cold brew immersion brewing.
Can I make cold brew without a cold brew maker?
Yes — a large jar, coarsely ground coffee, cold water, and a fine mesh strainer lined with a paper filter is all you technically need. Combine coffee and water in the jar, cover, steep in the fridge for 12–18 hours, then pour through the strainer into another container. It works, but the filtering stage can be slow and messy with very coarse grounds. A dedicated cold brew maker like the Toddy Home System handles this step for you cleanly and consistently, which is why most regular cold brew drinkers find one quickly pays for itself in convenience.
How long does cold brew last in the fridge?
Cold brew concentrate stored in a sealed container in the fridge will stay fresh for up to two weeks. Ready-to-drink cold brew (not concentrate) is best consumed within a week, as the lower concentration makes it slightly more susceptible to changes in flavour over time. Always keep cold brew covered — it readily absorbs fridge odours, which can affect the taste. The Toddy Home System's glass decanter seals well and is designed for fridge storage specifically.
Is cold brew stronger than regular coffee?
Cold brew concentrate is significantly stronger than regular brewed coffee — typically two to three times the concentration, which is why it's diluted before drinking. Once diluted 1:1 with water or milk, the caffeine content is broadly comparable to a regular cup of coffee, though this varies depending on your ratio, bean variety, and roast level. Darker roasts have slightly less caffeine than lighter roasts (the roasting process breaks down some caffeine), but the difference is modest. What cold brew is not is more acidic — it's significantly lower in acidity than hot-brewed coffee, which many people find easier on the stomach.
