Thunderkiss Coffee's Jason Valentine shares his secrets.

Cold brew coffee is the summer refresher made by immersing ground coffee in cold water overnight. Because no heat touches the beans, the drink is lightly sweet and surprisingly smooth. Jason Valentine, the roaster behind Thunderkiss Coffee, brews large batches of cold brew for local spots such as Katalina’s and Seventh Son Brewing Co.

Valentine discovered a love for coffee through Jovan Karcic, the owner of Yeah, Me Too, a tiny coffee shop on Indianola Avenue in Clintonville. Working in construction at the time, Valentine began roasting on his own, eventually purchasing a Diedrich IR-12 infrared roaster. In 2010, he launched Thunderkiss, first roasting at home and then out of North High Brewing’s production facility. In October 2018, he began roasting full time and recently moved to his own space in Milo-Grogan.

Like Valentine, many of the city’s coffee roasters produce excellent cold brew, although it’s just as easy to make at home. We asked him to share a few tips. thunderkiss.square.site

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1. Use light to medium roasts
Darker roasts can be flat, ashy and missing the necessary sweetness. Valentine recommends using naturally processed coffees, in which the coffee bean cherries are dried on raised beds in the sun. Then, it’s a matter of choosing beans with your preferred flavor profile. Ethiopian or Kenyan roasts, for instance, produce bright, fruity acids. Costa Rican beans often feature honey or citrusy sweetness, while Sumatran beans lean toward peaty and earthy.

2. Multiply by 0.125 to get your volume
Valentine says you don’t have to commit to brewing gallon-sized batches. Simply use any vessel, from a small pitcher to a French press; figure out how many ounces it holds and multiply it by 0.125. For example, a 10-ounce pitcher needs 1.25 ounces of coffee. (If you prefer a stronger cold brew, Valentine suggests rounding up the total by a half-ounce.)

3. Use a medium-grind coffee
Set your coffee grinder to a medium or “drip” grind setting. Too coarse and the brew is weak or flavorless. Too fine and it becomes difficult to filter.

4. Steep in water for 24 hours
Use whatever water you prefer: mineral water, filtered water from your fridge or even tap water if you like the flavor. Add the ground coffee to your container, fill with water, then stir vigorously until all the grounds are thoroughly soaked. Allow coffee to steep at room temperature or in the fridge for 24 hours.

5. Filter completely
Filter your brew using a paper coffee filter. For a richer or more chocolatey cold brew, filter through a cheese cloth or the French press screen.

6. Serve!
Pour your cold brew over ice. Add a splash of milk or cream if you like.

7. Refrigerate
Valentine suggests drinking your cold brew within a week, but it will keep its flavor in the fridge for up to 30 days, becoming less acidic and more full-bodied as time goes by.