Together, we’ve explored what cold brew is, how it differs from flash chill or iced coffee, and why it’s popular. We’ve also experimented with different cold brew makers and delved further into the effects of brew ratio, time, temperature, and other factors.
Now it’s time to talk about how to master the different variables for the best cold brew coffee recipe, and how to change them when you’re cold brewing at home –– no matter how! Let’s talk about:
- Picking the Right Roast
- Optimizing Your Grind
- Using the Best Water
- Controlling Your Temperature
- Locking Out Air
#1 | Picking the Right Roast
As with all coffee brewing, choosing your roast is an important piece of the puzzle.
A dark roast is ideal for those who want strong chocolatey flavors and a rich body. A medium-light roast (like our Haya blend) offers more subtle juice-like flavors and clean acidity, but only when brewed long enough, depending on your equipment.
- dark roast: milk-chocolatey, banana split, melted ice cream, possibly some nuttiness
- medium roast: lighter body with balanced sweetness and acidity, fruit nuances, mild to moderate chocolate
- light roast: very fruity and acidity-forward, “poppy”, subtle floral or herbaceous nuances (these can be very palate-specific), sometimes tea-like
#2 | Optimize Your Grind
Fine, Drip, and French Press grind sizes next to a nickel
Because cold brew extracts slowly and not as efficiently as a hot brew, a coarse grind helps to prevent over-extraction of some easily-extracted notes that could overpower the brew, by reducing total surface area. Make sure to grind coarse, but not quite to the point of a French Press. More like...French-ish.
This variable is also something that depends on your brewing gear. For example, in our brewing kit experiment, the Toddy clearly works best with super coarse grinds, while the various filter-in bottle brewers like the Hario Mizudashi were best with a medium-to-coarse grind, with room for taster’s preference.
That being said, no matter your method a high proportion of fines isn’t desirable. Even the low and slow extraction rate of cold brew can turn fines (with their greater total surface area) into over-extracted, bitter cold brew. Just like with hot brew, a quality burr grinder is highly suggested to get the most out of your specialty coffee beans. For this, our go-to suggestion is always the Baratza Encore. High-quality, lower cost, premium hand grinders are coming on the market all the time, but since this is cold brew, and you’ll be grinding A LOT, an electric grinder is probably the best.
#3 | Water Is Your Main Ingredient
It seems silly to say it, but it’s the truth: water is your dominant ingredient in making any coffee, including cold brew. We recommend using filtered water (not distilled!). If you want to get really in depth with it, we like our water to be around 150 ppm in total hardness (but don’t get too hung up on it). That’s not the same as distilled water, which lacks any minerals to provide the various ions needed for effective extraction. This leads into a broader discussion of water quality and coffee brewing.
If you do want to try optimizing your water for coffee brewing, experiment with Third Wave Water or Global Customized Water. Products like Third Wave Water can specifically add the necessary cations and anions to distilled water, without the fuss and expense of a complicated filtration system.
#4 | Control Your Temperature
“Cold” brew, in our opinion, is actually best when brewed at ambient temperature: 60 to 75 degrees.
Actual cold brewing — like in a refrigerator — can still make excellent cold brew, especially with darker roasts. But we have found that doing this for too short of time or with a roast that is light or medium will lead to less than desirable results. Your cold brew may taste flat and/or chalky. Many recipes advise brewing in the fridge, but we find this leads to an overall loss of flavor.
Once your cold brew is done, no matter what, ALWAYS store the finished coffee concentrate in the fridge, unless you consume it within a few hours. Treat it like a perishable product––because it is! Improperly caring for your cold brew coffee can turn this otherwise healthy beverage into a food hazard, and we’re only here for those great coffee moments.
#5 | Lock Out Air
Another variable in cold brew is air. We recommend covering your cold brew while it steeps, and then getting the finished concentrate into a sealed container and then into the fridge as quickly as possible when it’s done.
The longer the coffee is in contact with our lovely breathable atmosphere, the more quickly it oxidizes. This leads to loss of flavor. Also, the long steeping time gives more time for the stuff in the air to find its way into your brew, and we want our cold brew to be so fresh and so clean.
Go Forth and Brew!
We hope this series answered some of your questions about brewing cold brew coffee at home.
We think there's a reason cold brew coffee has caught on so widely and has had so much staying power. It combines some of the best parts of coffee — its taste, health benefits, and caffeine-boost — and combines it with an easy, hard to mess-up brewing method. If you're new or unacquainted with this beverage, we hope this series has been enlightening and helpful.
Happy brewing and feel free to reach out with any questions!
COLD BREW-OFF: HARIO VS. KINTO VS. TODDY