by Kady Matsuzaki
Photograph courtesy of Starbucks
Iced coffee season may be drawing to a close, but there remains a common misconception which even dedicated coffee drinkers may hold—that cold brew and iced coffee are the same drink. While cold brew is iced coffee’s more hipster counterpart, there are many differences between the two. Brewing method, taste and caffeine content all differentiate iced coffee from cold brew.
Traditionally, iced coffee is made by brewing regular hot coffee, made with hot water and finely ground beans and pouring that coffee over ice cubes. To keep the drink from becoming too diluted by the melting ice, the amount of ground coffee beans used to make the hot brew is often doubled. Therefore, iced coffee is virtually identical in taste, method and caffeine content to regular hot coffee.
On the other hand, cold brew is smoother, less acidic and less bitter. It often has strong chocolate or fruit notes and is much mellower than iced coffee. Cold brew’s smooth taste can be attributed to the brewing process. While hot water is used to brew iced coffee, cold brew is made using room temperature or cold water. By using cool water, the acids and oils that give hot coffee its bitter taste are never released. The coarsely ground beans are steeped for 12 to 24 hours, resulting in a highly caffeinated concentrate that can be diluted with cold water before serving.
Cold brew’s popularity has been steadily increasing nationwide, especially after it was introduced onto the Starbucks menu. The coffee chain announced a 25 percent increase in iced drink sales after it first launched Narino Cold Brew in 2015, according to a Bloomberg report.
The same report cites Starbucks’s desire to increase the number of stores that offer trendy cold brew on tap—from about 1,000 to over 1,500. Starbucks devotees will be able to enjoy frothy cups of cold brew poured the same way as beer on tap: at the push of a lever.
For those looking for the drink that packs the heaviest caffeine punch, the choice between iced coffee and cold brew is not always clear.
"Caffeine's solubility is primarily driven by temperature, such that at higher temperatures, significantly more caffeine will dissolve in solution than at cooler temperatures," said Joseph Rivera of Coffee Chemistry. "If you are using the same brew-to-water ratios, the cold brew will definitely have less caffeine than hot."
However, cold brew requires more beans per ounce of liquid in the brewing process, which could make up for the solubility difference. In addition, if drunk in its concentrated form, cold brew is shown to have significantly more caffeine per ounce than brewed coffee. For example, Stumptown’s highly concentrated Nitro Cold Brew contains 330 milligrams of caffeine in an 11-ounce can, as compared to a Starbucks 16-ounce iced coffee, which contains only 165 milligrams of caffeine.
Cold brew that has been diluted with water or milk, however, has a caffeine content comparable to regular iced coffee.
For those who have been avoiding coffee because of its acidity, which can cause digestive problems, there is still a viable caffeine source other than tea.
Joan Salge Blake, RD and Clinical Associate Professor at Sargent College, said cold brew “can be easier on the digestive system, particularly for people who struggle with heartburn or a sensitive stomach.”
The cold water-based brewing process for cold brew prevents most of the stomach-upsetting acids from being extracted from the beans, resulting in a milder beverage.
Regardless of which iced beverage you choose to try in the final weeks of warm weather, cold brew’s increasing popularity has made it just as easy to find in Boston and Cambridge as iced coffee. Caffe Nero, the newly opened coffee shop just past West Campus, Blue State Coffee and Pavement Coffeehouse all offer both iced coffee and cold brew around campus. Many national brands such as La Colombe, Stumptown and Blue Bottle sell their cold brew through retailers like Target.
However, cold brew tends to be more expensive than regular iced coffee at both chains like Starbucks and independent coffee shops.
Luckily, it is easy to make at home. Combine one and a half cups of coarsely ground coffee beans with four cups of cool water and let sit for at least 12 hours at room temperature. Once the mixture has finished brewing, all you have to do is strain out the coffee grounds and dilute with a little water or milk before drinking.