Tips from The Kitchn

I Tested Dozens of Cold Brew Coffee Makers — Here Are the 5 Most Important Things I Learned

published Sep 10, 2021
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Credit: Joe Lingeman

Although cold brew coffee is among the easiest Joe to make (theoretically!), the instructions that come with various cold brew coffee makers run the gamut from frustratingly vague to impossibly precise. Here are some tips I learned after testing a whole lot of cold brew makers (like a lot a lot) to help you decode and streamline those instructions.

1. You might have to do some math.

Instruction manuals really are all over the place with their measurement suggestions. The grounds might be measured in tablespoons, grams, ounces, or cups. Water may be measured in ounces, cups, milliliters, liters, or even half gallons. In order to properly compare the brewers and to standardize the math, you could find yourself doing a lot of conversion math. Tablespoons and cups, in particular, are best changed to something more precise, as they can have some built-in inconsistencies (e.g., a heaping tablespoon versus a level or scant tablespoon; some brewers list “cups” as 5 or 6 ounces, while the standard measurement is 8 ounces). Grams of coffee to grams of water is my preferred conversion for simplicity’s sake, but grams of coffee to ounces of water is also precise and less tedious. Once you have your ratio down at home, it’ll be easy for you to make consistent cold brew time-after-time.

2. Your grounds need to look like coarse cornmeal.

The majority of the cold brew makers call for a “coarse grind,” without specifying how coarse is “coarse.” For the sake of my tests, I used a standard coarse grind size — around the texture of coarse cornmeal — except when specified. For your own cold brew-ing, a grind size that ranges from the size of kosher salt to coarse cornmeal will do. Just avoid too fine a grind: This will make a sludgy or muddy-tasting brew.

3. The brewing sweet spot is a full 24 hours.

Another instruction point that may be somewhat vague is the recommended length of the steep. Most suggest 12 to 24 hours of steeping time, although brewers whose instructions specify brewing in the refrigerator may say anything from 8 to 12 to 24 hours and even all the way up to 36 hours. I find 24 hours to be the sweet spot: It results in a great brew and it’s easiest to remember, for me, as I can start my cold brew at 7 a.m. one morning and have it ready at the same time the next day.

Credit: Photo: Ghazalle Badiozamani

4. A cold brewer that makes concentrate gives you more control.

The majority of cold brew makers will create a concentrated product that is designed to be diluted with water or milk before consuming, but some make a ready-to-drink brew. Dilution is ultimately a matter of personal preference, but I like cold brew makers that produce a concentrate, as this gives you more control over the end result. I tried 1:1 (2 ounces cold brew to 2 ounces water), 1:2 (2 ounces cold brew to 4 ounces water), and 1:3 (2 ounces cold brew to 6 ounces water) with all of the brews. Many of the brewers’ instructions recommend 1:2 or 1:3 ratio of cold brew concentrate to water, but I found that a 1:1 or 1:2 ratio yielded the best flavor (before adding ice!).

5. Your cold brew will have a shelf life.

Some of the brewers recommend consuming the coffee “immediately,” while others say it can be stored anywhere from several days to several weeks in an airtight container in the fridge. The most common recommendation is that undiluted concentrate can stay fresh refrigerated in an airtight container for two to three weeks, while diluted cold brew should be consumed within a few days. 

Do you have a favorite cold brew tip? Let us know in the comments!