Do Not Put This Common Drink Flavor In Your Coffee

Flavored coffee is make-or-break territory. There are plenty of spices to elevate your regular cup of Joe (hello, PSLs). Yet, in Tasting Table's investigation into flavors that just don't pair well with coffee, there was one ingredient so popular in the wider drinks industry we had to try it in our java. It was a bad idea. As a general rule, avoid lemon in coffee at all costs. It annihilates any sense of acidity — something that's already precariously balanced in the average cup — and sends milk curdling. 

Here's the issue. Acidity is measured on a pH scale of 0 to 10, with lower numbers being intensely acidic and higher numbers ranking as alkaline. The average coffee sits at 4 to 5pH, while lemon is around 2 or 3pH. Just a drop can quickly send that scale sliding downwards, which is a nightmare for those who prefer milder cups.

Typically, milk is a common neutralizer for overly acidic coffee. But if you attempt to incorporate lemon into a latte or other dairy-based beverage it becomes a textural doomsday. On a scientific level, this curdled curse is triggered by disrupting tiny milk proteins called casein. These casein happily drift around as isolated individuals with a negative charge; disaster only strikes when something acidic neutralizes them. With a bit of lemon juice the casein will quickly clump, forming curdles visible to the naked eye. Play it safe, and don't ruin a good cup of coffee.

Considering all the information above, the general consensus is to skip the lemon when brewing coffee. With that said, though, the combination isn't entirely unheard of. You might recall the #coffeelemonchallenge on TikTok; users committed to a daily regime of citrus-flavored cups, with some citing profound weight loss benefits. Experts rapidly debunked this theory, though. Scientifically speaking, there's little supporting evidence that lemon-flavored coffee is beneficial to health. Unless you've got unusual taste buds, it's probably a good thing you sat that trend out.

If you're still feeling curious, research coffee lemonade and where to find it. There are home recipes to sample, too, like the Thunderbolt — a mix of lemonade and a double espresso shot. Interestingly, Thunderbolts receive better taste reviews; quantities definitely matter. Perhaps add small amounts of coffee to bulk measures of lemonade. Or subtler touches to coffee, like lemon peel adornments. If you decide to tackle this drink at home, it's worth learning some (non-dairy-related) ways to fix overly acidic coffee, just in case. And if you're feeling risk-averse, maybe stick to the classic lemon and tea combo.