When you work in coffee for enough years, you start to hear the same questions come up time after time. One of those questions that everyone eventually asks is, “What is the strongest coffee?”. If it doesn’t come in the form of a question, it is often a proud roaster or barista proclaiming to all, “Brazil has the strongest coffee!”, or “Turkish is definitely the most strong!”
The truth is, it’s a bit more complicated these bold, sweeping statements. What makes a coffee strong in the first place? What does strong mean when we are talking about coffee? These are vital components necessary to understand before we finally slap on a label for “World’s strongest coffee.”
First, what do we mean when we describe a coffee as strong? This term is often confusing because people in the coffee world use it differently than your average coffee drinker. Coffee people refer to the strength of coffee in terms of its concentration of dissolved solids in relation to the amount of water diluting it. Civilians use strength to describe strong flavor (normally bitter or roast flavor) or refer to its potency in terms of its caffeinated impact. We will focus on the latter as that is the only one we can determine generically, although coffee concentration plays into this equation.
Most people I talk to during their first coffee training seem to have the same idea about the strongest coffee – espresso. It is a common fallacy that espresso is the strongest coffee with the most caffeine content. Many Europeans describe American-style filter coffee as being watered down and weak. I believe this train of thought comes from its spirited cousin, alcohol. In the booze world, a shot equals a beer, so people often assume that a shot of espresso equals a cup of coffee. This is not true.
The strength and caffeine content of a coffee come from how the coffee is extracted while brewing. This extraction method includes water temperature and contact time between the grinds and water. The hotter the water, the faster the extraction. The longer the coffee sits in water, the more material will be dissolved into the water. Now that you understand these simple facts, it is easy to determine which coffees are the strongest.
Espresso is only 7-20 grams of ground coffee brewed for 20-30 seconds in 197-199 F water. A filter coffee is generally brewed 20-30 grams (individual cup) of ground coffee for 4-6 minutes using water between 204-211 F. Filter coffee is the clear winner for caffeine content. Turkish coffee is often brewed for a more extended period, 4-6 minutes with a sizable dose, so it is one of the more potent caffeinated brews you can make. Additionally, a French press, which also has a fully immersed dose for a longer brew time, is one of the stronger options.
Ultimately, it is often the cold brew coffees that end up with the highest caffeine count. Although cold brew uses cooler temperature water (50-70 F), it has the longest brew time, 12-24 hours. This unique brew method extracts a lot of material. So much that once brewed, it has to be diluted with more water just to be palatable. There we have it: cold brew is the winner.
If you want to kick your cold brew up another caffeinated notch, try doing it using Robusta beans. Robusta is the brother of the Arabica plant, so they have similar but individual flavor profiles, but Robusta comes with twice the amount of caffeine. Give that a shot and see what happens. Enjoy!