This article originally published in The Sturbridge Times, March 2017
By Elvis Dyer, Owner/Roaster, Sturbridge Coffee Roasters
Did you know – a dark roast has less caffeine than a medium roast? Many people think that strong, rich flavor of a dark roast indicates an extra dose of caffeine, however, as the beans roast, the caffeine is roasted out. So the longer the roaster “cooks” the beans, the darker the roast and bolder the flavor, however, less caffeine. A light roast, often packaged as “breakfast blends” contains the most caffeine, followed by medium roast. Not all coffees contain the same amount of caffeine, again, it goes back to the roasting process. A medium roast at one place can have more/less caffeine than a medium roast somewhere else as a single degree temperature in the roast can fluctuate taste and caffeine content.
How much caffeine should I have? According to the Mayo Clinic, moderate caffeine consumption is between 200-300 mg per day. Although averages tend to vary by reporting agency, you can find research supporting anywhere from 200-500 mg per day is considered safe.
How much caffeine am I having? Making coffee is not a precise science. Something as simple as where the coffee was grown can impact the caffeine content. The roast level, blend or variety of the coffee, the brew method and a handful of other factors including water temperature, grind size and dwell time can also affect the caffeine content. That is why, when you see a caffeine content listing for coffee, it is generally an approximation, at best. However, based on these approximations, you can guess, to a decent level of certainty, how much caffeine you are ingesting with each cup. According to the Center for Science in the Public Interest (CPSI), caffeine quantity in drinks (on average) is:
Brewed Coffee (referring to any method of coffee preparation where hot water comes in contact with coffee grounds for an extended period of time): 100 to 200 mg per 8 ounces (12.5-25 mg per 1 ounce)
Instant Coffee (made by roasting and grind the coffee bean, and then extracting the flavor by placing the coffee in a solution of water and then dehydrating the solution i.e. freeze drying): 27 to 173 mg per 8 ounces (3.4-21.6 mg per 1 ounce)
Espresso: 30 to 90 mg per 1 ounce. The average shot of espresso contains approximately 64 mg of caffeine. You will often hear that espresso has more caffeine than a cup of coffee. Generally, that is wrong and a SINGLE shot of espresso does not contain more caffeine than a single cup of coffee. The caffeine content really adds up when you start consuming multiple espresso shots.
Decaf Coffee: 3 to 12 mg per 8 ounces (0.4-1.5 per 1 ounce). Yes, there is caffeine in decaffeinated coffee. In the United States federal regulations require that in order to label coffee as “decaffeinated” the coffee must have had its caffeine level reduced by no less than 97.5 percent. Decaf should range somewhere in the 2-4 mg of caffeine per 6 oz cup range.
So what about Iced Coffee? Brewing coffee at hot temperatures extracts more caffeine from the beans. However, iced coffee is typically served over ice. Therefore, you are taking the caffeine content of the aforementioned hot coffee, and diluting it by about 30% (the average amount of ice used in an iced coffee beverage). Cold Brew Iced Coffee is typically brewed as a concentrate without heat ever hitting the solution or extracting caffeine. Typical off-the-shelf cold brew machines recommend a coffee-to-water ratio of between 1:4 and 1:8, compared with a more typical drip coffee ratio of 1:15 or 1:25. This alone leads to a higher caffeine concentration. And the brewing time of cold brew is much longer – usually about 12 hours. However, as a concentrate, cold-brew coffee is typically served over a cup full of ice, which levels things out a bit.
If you are looking for the most caffeinated cup of coffee – choose a light roast, opt for finely ground, know your ratios of water to coffee, and add a shot of espresso for the extra caffeine boost.