How Long You Should Steep Your Cold Brew
Dandelions fill the parks and yards, trees are in full bloom, and the days are getting longer. That can only mean one thing — cold brew season has arrived. Devoted fans may enjoy their cold brew throughout the year, but for most of us, traditional coffee's chill cousin tends to take center stage during the warm months of Spring and Summer. Cold brew has become one of the most popular ways to enjoy a cup of joe and has changed the business for many cafe owners, but you can also find it at most coffee shops, including your local Starbucks and Dunkin'. It can even be easily made at home with coffee, water, and a little bit of time — though exactly how much time is a little tricky to lock down.
Not to be confused with iced coffee, cold brew is a process of allowing coffee grounds to steep in room temperature water over a long period of time. According to Joe's Coffee, this longer, cooler extraction method draws different chemical compounds out of the coffee that may make the drink more healthy, and absolutely creates a less acidic and less bitter drink than traditional hot coffee. Because all of the flavors drawn out of the coffee are stable at cooler temperatures, it also tends to keep better (via Home Grounds). This means you can brew a batch that will last for days without losing any flavor when stored correctly.
The steep time of a cold brew impacts its flavor
According to Joes' Coffee Company, cold brew takes a significantly longer amount of time to brew properly compared to a traditional cup of hot coffee. Espresso can be ready in as little as 30 seconds, a pour over may take five minutes, but for cold brew coffee it's going to take about 18 hours to fully extract the right flavors from the coffee grounds (via National Coffee Association). Brewing with hot water allows the water to seep into the grounds more quickly and extract flavors that are more soluble (via Joe's). When that heat isn't present the water is relying on exposure time — time spent with the coffee grounds totally immersed in the water — to draw out most of the flavor compounds.
There are a lot of variations, but Joe's recommends 18 hours as a solid extraction time for a standard batch of cold brew at home. This gives the water plenty of time to create a full flavor without going too far and drawing out the less desirable compounds that may result in a loss of sweetness.
It's also important to remember that ground size will impact the extraction process. Joe's Coffee recommends using a slightly more coarse grind — something close to the appearance of Himalayan rock salt — for the best cold brew.