Hot Brew vs Cold Brew Coffee
Hot brewing is relatively self-explanatory. Whether you're using a Keurig, Nespresso, French press, pourover, or Aeropress, you're already familiar with the method and the results. In most cases (espresso machines, the Nespresso and Aeropress being exceptions), you're getting standard-strength coffee that's ready to drink in a matter of minutes. Want to ice it? Add ice. Stir. Done. The use of hot water releases more of the grind's soluble compounds, giving you more flavor (and more acidity). It also uses less coffee (typically two tablespoons of ground coffee per eight ounces of water).
Cold brewing uses tepid (room temperature) water, a lot more coffee (two ounces of coffee per eight ounces of water), and a lot more time (up to 24 hours). Quite a bit of this is to make up for the decreased solubility brought on by the use of colder water. What results, therefore, is a lower-acid, typically less-bitter, and highly concentrated brew, but one that's also not quite as nuanced as coffee that's been brewed hot. If you have the foresight to whip up a batch, another advantage of cold brewing is that once the concentrate is made, it's a very quick way to make your morning coffee.
There's a third option that we found courtesy of Boston NPR affiliate WBUR and barista San Bellino: start with a hot bloom, and finish by cold brewing. The recipe calls for eight cups of water to one pound of coarse ground coffee. One cup of water will be brought to a near boil (205 degrees) and poured over the grounds, which can be agitated and left to bloom for about 90 seconds. Adding the remaining seven cups of cold water halts the bloom and starts the cold brewing process. After 24 hours, the coffee can be strained or filtered and the resulting concentrate is ready for use. The flavor profile that results from this method has all the benefits of the usual cold brew, but adds just a bit more complexity.
Aside from water and coffee ratios -- and even those can vary by brewing method -- it's not as though there's a single right way to brew your coffee, whether you're drinking it hot or cold. Depending on your flavor preferences -- the complex acidity that comes with brewing with hot water, the concentrated, flatter, but mellower profile that comes with cold brewing -- you might find one method and stick with it. You may also decide that you'll approach hot and iced coffee as two different drinks, and appreciate each for the differences it can give you even with the same beans as a starting point.