Four years ago, I learned about cold-brewing iced coffee. According to the story in the New York Times, cold-brewed coffee would taste completely different than hot coffee that was then chilled.
“Without the bitterness produced by hot water, the cold-brewed coffee had hints of chocolate, even caramel,” the author wrote.
I was curious to try cold-brewed coffee, and even printed out the recipe, but never got around to it. When Harold McGee, the Times’ food/science columnist, wrote about the differences between cold- and hot-brewing earlier this week, I knew I needed to try out the different brewing methods myself.
I wanted to do this as scientifically as possible, but not tax myself (or my wallet) too much. There are a variety of specialty cold-brew systems that promise superior coffee. I wanted to know how the simplest cold-brewing method – combining ground coffee and cool water and letting it sit for 12 hours – would taste.
My typical coffee brew strength is 20 grams of coffee and 12 ounces of water. That happened to be the recommended ratio for cold-brewed coffee. I brewed two identical cups of coffee – one with hot water in my automatic coffee pot, one with cool water sitting at room temperature in a water glass overnight.
The next morning I filtered the cold-brewed coffee, popped it into the refrigerator for a couple hours, and paid a visit to Starbucks to purchase a control iced coffee.
Here’s how I set up my tasting experiment: I wanted to know how the three varieties of iced coffee tasted black, and with milk and sugar.
I poured each coffee into a glass I had marked on the bottom. Then I mixed up the glasses so I wouldn’t know which one was which. This was as close to a double-blind study as I could get while serving as both the experimenter and subject. I tasted each coffee (making sure to munch on a palate cleanser in between) and made notes, then ranked them.
The home hot-brewed and then chilled coffee was my favorite, followed by the Starbucks control. The cold-brewed coffee was my least favorite. I could taste the difference between the Starbucks brew and the two home-brewed coffees (due to the different beans and roasts). I preferred the “wrong” coffee, however. In my tasting notes I wrote that the hot-brewed iced coffee was “the least bitter and most mellow,” while also being “bright.” The qualities usually attributed to cold-brewed coffee I was tasting in the hot-brewed cup.
On to part II of the experiment. I never drink iced coffee black, so of course I wanted to see how milk and sugar changed the tastes of the iced coffees. I made a batch of simple syrup, then added 2 tablespoons of whole milk and 2 teaspoons of syrup to each coffee. I put out fresh Post-It notes, re-shuffled the glasses, and tasted again.
While the three coffees tasted pretty similar in black form, after adding sugar and milk I had a clear least favorite. In my tasting notes I wrote that one coffee (which turned out to be the cold-brewed cup) had a “bad aftertaste that lingers.” My favorite version had “a balanced coffee flavor.”
What conclusions can I draw from this test? On this day, with this type of coffee (a medium roasted arabica bean from Colombia) cold-brewing coffee definitely didn’t perform well. I have no doubt that it’s possible for cold-brewed coffee to taste better, but I think special equipment is required to get the desired results.
It might not be elegant, but I’ll stick to popping my hot coffee in the fridge when I want an afternoon pick-me-up.