Maybe you like your iced coffee with just a splash of milk. Maybe you like it with four spoonfuls of sugar and a healthy pour of flavored creamer. Whatever your preference, you may not have thought about putting lime juice in it.
Adding citrus to your iced coffee might sound off-putting, but it's actually refreshing. While mixing citrus juice with your iced coffee has become a relatively recent trend, it has evolved from what invading French soldiers were doing in the 1830s and 1840s while being held prisoner in Algeria. They didn't have access to many resources for their cups of joe but found refreshment by adding cold water.
Some historians believe that this Mazagran-style coffee (named after the fortress where they were held) was the original iced coffee. Later, the drink became popular in French coffee shops and bars where it was served with ice and lemon, like the modern lemonade coffee trend . Making your iced coffee Mazagran-style with lime juice is a similar principle, just squeeze some of the fresh fruit into your cup.
Along with creating a refreshing drink, especially during the summer, it reduces the bitterness of espresso and poorly roasted coffee beans. You can add a splash of creamer for sweetness, but be careful about which type you add. Regular coffee creamer and milk are likely to curdle because of the lime's extra acidity.
Sweetened condensed milk is a better option because its chemical profile is different, and you can use it to make corn milk for your coff.