Making cold brew at home is a lot simpler than you think it is. All you need are your favorite coffee beans, cold water, and 24 hours for cold coffee that is smooth, ever so slightly sweet, and still bursting with bold coffee flavor.
If your coffee isn't already ground, grind to coarse grinds with a coffee grinder.
Place coarsely ground coffee into a large container with a spout, preferably glass or ceramic (just not metal) and add the filtered water. Stir with a wooden spoon or plastic spatula (again, no metal), cover tightly with plastic wrap or a lid, and store in the refrigerator for at least 12 hours3 but ideally 24 hours.
After your ground have been steeped for as long as you'd prefer, fit a fine mesh strainer with some cheesecloth or a paper coffee filter and place it over a measuring cup, then pour the soaked grounds into the strainer.
Measure the amount of coffee concentrate you have, and dilute as desired4 into a vessel large enough for the amount of cold brew coffee you will wind up with. Discard grounds. Store in the refrigerator and use as needed. You may also leave the concentrate as is and dilute per cup.
To serve hot: simply dilute coffee concentrate with hot or boiling water and keep in a thermal carafe. Again, you may leave concentrate as is and dilute per cup.
Add cream/milk/sugar5 to your liking and enjoy.
Coarsely ground coffee: you can use fresh grounds, but I always prefer to grind my whole beans right before brewing for best taste. This is our favorite coffee grinder.
Filtered water: since you aren't heating this coffee, it's best to use filtered or bottled water for purity and best taste.
Steeping time: the longer your grounds steep, the deeper and bolder the coffee flavor. It is best to go the full 24 hours, but 12 hours works in a pinch.
Dilute the cold brew concentrate: I suggest a coffee:water dilution of 2:1 if you like to add cream, and 1:1 if you like to drink it black.
Adding sugar to cold coffee: since granulated sugar does not dissolve well in cold liquid, I suggest keeping a simple syrup on hand. To make simple syrup: heat a 1:1 ratio of water:sugar in a small saucepan over medium heat (I typically do 1 cup:1 cup) until sugar is dissolved. Allow to cool and store in the refrigerator.