It’s the hottest time of the year here in Seattle, and for many of us, that means the only coffee we’re drinking is cold. We thought we’d take the time to explain how we make our iced coffee and how you can make your own at home.
At Elm, we prefer iced coffee to cold brew. The difference between the two is widely misunderstood, so this is how we categorize it: Cold brew is made by immersing coffee in cold water for a long period of time, typically 8-24 hours, then filtering and serving over ice. Iced coffee, however, is brewed like filter coffee, except a portion of the total water weight is replaced with ice in the carafe. Essentially, you are making a more concentrated brew that is immediately diluted and chilled over ice.
The important difference between cold brew and iced coffee is the extraction. Cold brew, since it is using cold water over a long period of time, is very challenging to extract to a proper level. (More on extraction here) As a result, a lot of cold brew tastes relatively flat and samey, regardless of the coffee used, with only vague flavors of chocolate and nuttiness coming through. Iced coffee brews with hot water, and can extract more of the flavors present in the coffee, especially the more fruity, floral, and acidic stuff that is leveled off by cold brewing. As a result, we feel that iced coffee does a better job of representing the range of flavors present in our coffee, and is our preferred method.
That all said, how do you do it? We make our iced coffee on a FETCO drip brewer, but the method can be easily replicated with any filter coffee method, whether that is a Hario, Kalita, Chemex, or drip machine. You are going to want to start with a slightly higher ratio of coffee to water than usual, about 1:15, ground slightly finer than your usual filter grind. For example, 32 grams of coffee to make a 500ml brew. This will end up stronger than we like for regular filter coffee, since it will be served over ice in the end.
Next, you are going to replace 40%-50% of your brewing water with ice in the carafe, depending on how cold your ice is. The ice will melt as you brew onto it, chilling it immediately and diluting it to a pleasant strength. For the previously mentioned 500ml brew, this means you would brew with 300ml of water and 200g of ice in the carafe.
From there, you can go ahead and brew your coffee just like you would any other filter brew. Bring your water to a boil in your kettle, bloom your grounds for 45 seconds with 2x-3x its weight in water, stir the bloom to ensure every part of the bed is saturated, and then pour your remaining water dose in slow circles until you reach the target weight. Your total brewing time should be around 3 minutes. Once it drains completely, go ahead and stir your coffee to make sure the ice is fully dissolved into the brew, and then serve it over ice in a glass. You’ll find it will be a perfectly chilled, complex cup, perfect for summer days.