The Case for a Coarse Grind
The first non-negotiable for true cold brew is coarsely ground coffee. Unlike a hot brew that uses high temperatures to extract flavour in minutes, cold brew is a long, slow dance between water and coffee that can last 12 to 24 hours. During this extended
steeping time, the grind size is everything. A fine grind, like the kind used for drip coffee or espresso, has a massive amount of surface area. If used for cold brew, it would over-extract, releasing bitter compounds long before the steep is complete, resulting in a harsh and silty concentrate. A coarse grind, with particles similar in size to sea salt, provides the perfect balance. It allows the water to slowly and gently pull out the desirable flavour compounds—the sweet, chocolatey, and nutty notes—while leaving the harsher, more acidic elements behind. This slow, controlled extraction is fundamental to achieving cold brew's signature smooth profile.
The Power of Patience and Cold Water
The second key ingredient is patience. Cold brew gets its name because it never interacts with heat. Instead of using temperature to force a quick extraction, it relies on time. Steeping the coarse grounds in cold or room-temperature water for an extended period—typically between 12 and 24 hours—fundamentally changes the chemical profile of the coffee. Hot water is very effective at dissolving coffee's soluble compounds, including the acids that can give hot coffee its bright, but sometimes sharp, taste. Cold water is much more selective. It extracts flavour far more slowly, and it's less efficient at pulling out certain acidic compounds, like chlorogenic acids. Studies have shown that this can result in a brew that is significantly less acidic than its hot-brewed counterpart, making it smoother and often gentler on the stomach. This long, patient steep is what creates that mellow, naturally sweet, and full-bodied flavour that has made cold brew so popular.
Your Simple Brewing Ratio
While you can find countless recipes, a great starting point for a cold brew concentrate is a 1:4 or 1:5 ratio of coffee to water by weight. If you don't have a scale, this translates to roughly 1 cup of whole beans (which you'll then grind) for every 4 to 5 cups of water. This will create a strong concentrate that is meant to be diluted. Don't feel locked into a precise measurement; this is a forgiving process. You can start with a 1:4 ratio, and if you find the resulting concentrate too strong after dilution, you can simply adjust to a 1:5 or 1:6 ratio for your next batch. The idea is to create a base that you can easily customize with water, milk, or ice to your exact preference.
The Step-by-Step Method
Making cold brew requires no fancy equipment. A large mason jar or any pitcher will do. First, combine your coarsely ground coffee with cold, filtered water in your container. Stir gently to ensure all the grounds are saturated. Cover the container and let it steep. You can leave it on the counter at room temperature for 14-20 hours or in the refrigerator for 16-22 hours. Many find the sweet spot to be around 16 to 18 hours, but this is a matter of personal taste. After the steeping is complete, it's time to strain. You can pour the mixture through a fine-mesh sieve lined with cheesecloth or a paper coffee filter. If you own a French press, you can brew in the carafe and then simply press the plunger down to separate the grounds. Store the finished concentrate in a sealed container in the fridge, where it will stay fresh for up to a week.
