By Lena Duer & Madison Mace
With the summer heating up, many coffee lovers find themselves searching for a refreshing way to enjoy their daily caffeine. For many, the choice is cold brew. Cold brew has become a summer staple best known for its smooth, full-bodied flavor. But what exactly is cold brew, and how does it differ from other popular coffee styles?
The History of Cold Brew
Cold brew is far from modern, with its history dating back to the 1600s. This was around the time when coffee was introduced to Japan by Dutch traders. Tea had already been brewed using cold water as brewing over open flames was too dangerous on the wooden ships. A drip tower was used to drip cold water over the coffee grounds for several hours to create a brewed concentrate. While there is no set date for when this coffee method was introduced, it has since paved the path for modern cold brewing methods.
In the 1800s, a similar brewing concept emerged during the Battle of Mazagran. French soldiers stationed in Algeria began mixing a sweetened coffee concentrate with cold water to create a refreshing drink for the desert climate. During this time period, liquid coffee concentrates were becoming more widespread in the military as boiling water was not always readily available. This variation of cold coffee became known as Mazagran, and is still enjoyed today with additions like lemon, sugar syrup, or rum.
Cold brew continued evolving into the 20th century. In the 1960s, American chemical engineer Todd Simpson patented the Toddy System. This system is the blueprint for cold brew production, and was inspired by the coffee concentrates Simpson experienced while abroad in Peru. The Toddy System standardizes cold brew concentrate preparation and is widely used in cafes and home coffee stations to this day.
The Science Behind the Brew
Cold brew’s signature difference from traditional coffee is in its production using room temperature or cold water rather than heat. This temperature difference significantly alters the coffee ground extraction.
Coffee extraction occurs when water dissolves the various compounds from the coffee grounds. The bright acids in the coffee grounds require higher temperatures to dissolve. Without the heat, these acids are slowly extracted. The aromatic oils in the grounds are also not fully vaporized when using colder water, causing them to stay in the liquid which contributes to the thicker, syrup-like texture in cold brew. The bitter compounds are also less soluble, reducing the overall bitterness in the extraction.
When crafting cold brew, the lower water temperatures combined with a brewing period between 12-24 hours slows the extraction process. This creates a unique flavor profile for cold brew with 50-60% less acidity than a hot-brewed coffee, a full-bodied, heavier body, and reduced bitterness in the flavor profile. When the concentrate is mixed with water, this creates a rich, smooth cup of coffee.
Cold Brew vs Iced Coffee
The type of coffee most similar to cold brew is the classic iced coffee. Both are great options for a refreshing burst of caffeine, but their methods of brewing offer up completely different experiences. Cold brew is made using cold or room temperature water and is steeped for 12-24 hours, creating a concentrate that is lower in acidity, smoother in flavor, and can be stored in the fridge and enjoyed for up to 7-10 days after it’s brewed.
Iced coffee, on the other hand, still relies on heat. Made from hot-brewed coffee that is then cooled over ice, it’s quick to prepare and maintains the aroma and distinct acidity of a hot cup; however, the quality of iced coffee also degrades faster due to oxidization, so it is best to enjoy your iced coffee immediately after brewing.
Cold brew and iced coffee are both summer staples, but their distinct brewing processes and flavor profiles create two different experiences.
Making Cold Brew at Home
Cold brew is one of the most accessible brewing methods. It requires minimal equipment, and it offers some flexibility based on what items you have. To make cold brew concentrate, you will need coarsely ground coffee, room temperature or cold water, and a very fine strainer, such as a cheesecloth, fine mesh strainer, or a nut milk bag. You may also use a Toddy System if available.
The steps to brewing are simple:
1. Grind your coffee. You’ll want very coarse coffee for this process to avoid sediment during extraction. A standard pre-ground bag will be too finely ground. It’s recommended to buy whole bean coffee and grind it at home or at a local store with a grinding station.
2. Combine coffee and water. In a container, combine the coffee grounds and room temperature water in a 1:4 coffee to water ratio by weight.
3. Stir well. This ensures the grounds are thoroughly saturated. Dry pockets of grounds will not extract.
4. Steep. Cover the container and leave to steep at room temperature for 12-18 hours, or in the fridge for 18-24 hours.
5. Strain. After your coffee is done steeping, use the fine mesh strainer, nut milk bag, or cheesecloth to separate the grounds from the concentrate. Be patient in this process, do not press or squeeze the grounds while straining. This pushes more of the bitter compounds through, gravity will take care of the work for you.
If desired, you may also do a second strain through a paper filter. This traps more of the remaining micro-grounds and oil, creating a thinner body that is clean, light, and crisp on the tongue. Note that a second pass through a paper filter is not required to make a good cold brew, it’s just personal preference.
To store: Keep the finished concentrate in a sealed container and refrigerate. Your concentrate is best used within 7-10 days but will last up to 2 weeks.
To serve: To enjoy, dilute using equal parts cold brew concentrate and either cold water or milk.