How to make cold brew in a French press?

Using a French press for cold brew is one of the most effective ways to utilize equipment you likely already own. Because cold brew relies on immersion brewing—where coffee grounds remain fully submerged in water for an extended period—the French press is naturally suited for the task. Its built-in mesh filter eliminates the need for paper filters or specialized cold brew systems, making it a model of brewing convenience.

To begin, you must adjust your grind size to a coarse setting. Because the contact time is significantly longer than hot brewing, a fine grind would lead to over-extraction, resulting in a muddy, bitter cup. A coarse grind ensures that the water extracts the desired sugars and oils without pulling out the harsh, astringent compounds that can occur during such a long steep.

Regarding the ratio, you are essentially creating a concentrate. A common starting point is a 1:4 ratio by weight (e.g., 100g of coffee to 400g of water), though you can adjust this based on your preference for strength. After adding your water, give the slurry a gentle stir to ensure all grounds are fully saturated, then place the lid on top to keep out debris. You do not need to press the plunger down until the steeping process is complete.

Steeping time is the most flexible variable. While 12 hours is a standard minimum, many enthusiasts prefer 18 to 24 hours for a deeper, more robust flavor profile. Since the process happens at room temperature or in the refrigerator, the extraction is slow and steady. Once the time has elapsed, simply press the plunger down slowly. The resulting liquid is a potent concentrate that should be diluted with water or milk to taste.

In practice, this method offers incredible consistency and ease. By keeping the concentrate in your refrigerator, you have a ready-to-drink base that lasts for several days. It removes the need for daily brewing rituals, allowing you to simply pour, dilute, and enjoy your coffee whenever you need it.