Ten years ago cold brew coffee was not nearly as pervasive as it is today. If it was on café menus it might have been tucked up in a corner under “other”, and many might have called it iced coffee because at the time a clear delineation had not been made.
Now it’s everywhere. From 2011 to 2016 the US cold brew market grew by 580%. By 2017 about 1 in 5 new coffee launches was a ready to drink cold brew beverage.
So what is cold brew? And how did we get here? Does it really have more caffeine than other brew methods?
Cold brew’s success can be attributed to its simplicity. All you need it coarsely ground coffee, room temperature water, and about 12 hours and you’re good to go. Every other brew method requires a contraption of some kind, but to make cold brew you only need a container to hold water and coffee, and some cheesecloth or a filter to separate the grounds at the end.
While it feels relatively new, cold brew has been around since at least the 1600s. The Dutch get credit for the first version of cold coffee. They developed a brewing method to make large quantities of coffee so that sailors would have a ready to drink coffee at sea. This coffee might have been brewed hot but was stored and available in vats, allowing sailors to avoid dangerous fires on their ships.
When Dutch merchants visited Asia coffee gained popularity in Japan. Cold brew gained traction in Kyoto with the use of elaborate looking devices that slowly drip room temperature water over coffee grounds and into a container below. The taste of is slightly different than our standard cold brew today as the coffee and water are not in continuous contact the whole time.
By the 1800-1900s different versions of cold coffee emerge, such as a coffee syrup and cold water beverage (1840s, French occupied Algeria), and coffee cut with chicory (early 1900s, New Orleans by way of France). In the 1960s Todd Simpson traveled to Peru and noticed a practice of brewing coffee cold and then heating it up for service. He returned home to America and promptly invented the Toddy brewer.
A few years after the invention of the Toddy, the first ready to drink cold brew coffee began to be sold in Japan by the Ueshima Coffee Company. Sales were slow at first but took off in the early 1970s as consumer habits changed with the widespread use of vending machines.
Until recently there has been very little research done on cold brew coffee. A group of scientists had planned to present a study in March that compares the chemical makeup of cold and hot coffee, but due to COVID-19 they opted to release their findings in a virtual poster session. They brewed both hot and cold coffees at a ratio of 1:10, a standard recipe for cold brew, and compared levels of caffeine, acidity, and antioxidants across different roast levels.
Researchers found that caffeine levels were almost identical for both hot and cold brewed coffee. We notice a difference in caffeine content of these brew methods not because of any chemical difference but because of the typical concentration used when brewing. While cold brew is typically brewed at a 1:10 ratio hot drip coffee is generally brewed between 1:15 and 1:18, making the resultant beverage of a hot brewed coffee less concentrated with, and thus less caffeinated.
When it comes to acidity “Cold brew coffees across all three roast temperatures were slightly less acidic than their hot brew counterparts. As roasting temperature increased, the total titratable acidity (TA) of all coffees decreased”. Their findings confirmed what we might expect. Cold brew extracts slightly less of the organic acids present in coffee, and there is increasingly less acid the darker a coffee is roasted.
One interesting finding from the study is the level of antioxidants present in coffee. The study demonstrates that heat encourages the extraction of antioxidants and that the concentration is heavily dependent on roast level. With lighter roasted coffee the antioxidant level of cold brew was slightly less than hot brewed coffee, but when comparing dark roasted coffees researchers found that cold brew had nearly 30% less antioxidants than its’ hot brewed counterpart.
You can view the virtual poster presentation here: https://www.morressier.com/article/role-roast-chemical-characteristics-cold-brew-coffee/5e736c70cde2b641284abdff
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