What’s your go-to add-on to your brewed coffee? Sugar? Cream? Maybe chocolate powder or a dash of cinnamon? How about a pinch of salt in coffee? Well, the Navy during World War II used to do that.

The Practice of Adding Salt in Coffee in the Navy

Crewmen have coffee aboard the USS Corvina while docked at New London, Connecticut, in 1943. (Nationals Archives and Records Administration)/Military.com

It all started when navy Secretary Josephus Daniels banned alcohol “on board any naval vessel, or within any navy yard or station” to put an end to the officers’ “wine mess.” Our sailors had to be fueled for their everyday naval works, so what’s else was left to do but rely on the coffee beans’ caffeine to keep them up, regardless of the time. You see, they had to work round the clock on different shifts, so they had to keep the coffee brewing all the time, ready for whoever needed a cup of steaming alertness. If you’re a coffee-lover, you’ll know that brewing a pot of coffee longer than necessary will result in a terribly bitter taste. You could try to fix it, as mentioned above, by maybe adding sugar or cream or perhaps even trying to water it down. For the WWII mariners, the most convenient and readily available quick fix was table salt. And so, as weird as it may sound, they started adding a pinch of salt to reduce the bitter taste of their coffee and make it bearable, if not better.

The practice could also be attributed to the fact that the desalination process of the seawater to turn it into drinking water couldn’t remove all the salt, thus resulting in a slightly salty-tasting cup of coffee that became the normal taste of coffee to sailors.  After they left the fleet, coffee in the civilian world just didn’t taste right without a slightly salty taste.

The Science Behind The Practice

Salt in a cup of coffee. Photo from VinePair Inc.

Did the trick really work? The answer is yes. Let’s look at the Science behind our seafarers’ practice to understand how it worked.

First, we have to understand what makes the coffee bitter. When coffee is roasted, the beans release two compounds: chlorogenic acid lactones and phenylindanes. The length of the roast affects the bitterness level of the coffee, so the darker the roast, the more bitter it’s going to be. At the same time, extraction affects the taste. Things like using water that’s too hot, letting your coffee sit too long in the French press, or maybe using the wrong grind size could all lead to over-extraction, too.

Now, our taste buds. Our taste buds are sensory organs that enable us to taste sweet, salty, sour, bitter, and umami flavors. Our taste buds react kind of differently to bitterness compared to other flavors. Whenever we eat or drink something bitter, calcium ions are sent to our brains while salt or sodium ions activate salt receptors on our palate. When presented with both flavors at the same time, it can lead to cross-modal perception, which makes our brain somehow cancel out the bitter taste of the coffee and “highlight” its sweet notes instead. Although you have to be careful in making sure you only use the right amount of salt, you want a cup of coffee, not a salt gargle.

Other Cultures

Turkish coffee. Photo from Hurriyet Daily News

Now, it might be your first time hearing about this practice, but countries like Turkey and Hungary are not new to this idea.

In Hungary, coffee fans are known to add salt to their cups of coffee or use seawater to brew their coffee grounds.