Sugar and coffee: old friends
Next to milk, sugar is the most common ingredient people put in their coffee. It seems normal to see bowls of sugar on café tables or sachets decorating the saucer of espresso. But why do we actually put sugar in our coffee?
It's because of the basic taste of coffee.
Coffee is naturally bitter in taste. Because of the original function of taste - to alert us to things that could be dangerous if consumed - we perceive certain compounds as bitter. Caffeine, which is potentially toxic in large quantities, tastes bitter to discourage us from taking it. Fortunately, it's perfectly safe in the amounts found in a cup of coffee (too much is never good, though, and if in doubt, discuss the effects of caffeine with your doctor), but that doesn't change the fact that we perceive it as bitter.
However, caffeine is not the only cause of the bitter taste in coffee. Roasting involves the controlled burning of green coffee so that we can extract more flavors and make a stronger coffee. Like anything that is burned, this is also associated with bitterness, the darker the roast the more bitter the coffee.
Balanced flavors
How can sugar help to mitigate this bitterness?
Taste is ultimately relative, meaning that while you can't "remove" bitterness from the cup, you can mitigate it by balancing it with the other main flavors - sweet, sour and salty. Balancing these flavors is the key to a tasty beverage because it means that all the different taste receptors on the palate are stimulated. This state of balance is sometimes referred to as the "fifth taste": umami.
No one wants to drink a salty coffee, and acidic coffees are a relatively new trend that can only be achieved with lighter roasts that aren't as bitter in the first place. Sugar is therefore the most popular way to balance the bitterness of coffee.
Just a little sugar can be enough to transform the bitterness from a dominant component to a complementary one. Of course, if a coffee tastes only bitter, this can be unpleasant. However, if this is balanced by a touch of sugar, the bitterness becomes one of several flavors and adds to the complexity of the cup.
Different types of sugar
White, brown, raw, cubed or candied sugar - there are many different forms of sugar you can use. While white sugar is probably the cleanest form of sugar thanks to its thorough processing, many people prefer raw or brown sugar. These types of sugar are less refined and therefore tend to have a more complex flavor that adds a little more interest to the cup.
After all, each of us has a different palate and has different sensitivities to different flavors. Some people are very sweet, while others love bitter. So it's up to you whether you want to add sugar to your coffee: however, our advice is to try it first.