Ask most people what coffee tastes of and bitterness comes up first. Yet plenty of coffee drinkers insist that a good coffee can be sweet. Is that true? Does coffee actually carry natural sweetness, or is it something our senses invent? The question comes up as much behind the bar as it does with customers who are starting to notice the finer points of the drink.
Where the sweetness in coffee comes from
Contrary to what most people assume, coffee contains only trace amounts of the substances responsible for a sweet taste. The sweetness you notice while drinking it is the product of several things at once. One of them is the crossmodal effect, a neurological phenomenon in which input from one sense changes how you perceive another. Aromas of vanilla, caramel or chocolate in a coffee can produce an impression of sweetness even with no sugar in the brew. Those aromas turn out to be the key: the sweetness is closer to an interpretation by the senses than to an ingredient in the cup.
The roast profile plays a big part too. Lighter roasts hold on to more acidity and to the delicate fruit notes we tend to read as natural sweetness. The point of the process is to keep the substances already in the bean intact so you can still find them in the finished brew. The bean itself matters as well, because variety and processing method are decisive. Coffees with natural fruit notes, from Ethiopia or Kenya for instance, often read as sweet because of organic acids that remind us of fruit. On top of that, how the coffee is farmed and how carefully it is picked both shape the final profile.
What happens to the sugars during the roast
During roasting, the natural sugars in green coffee caramelise. In that process the sugars turn into aroma and flavour compounds and give the coffee its characteristic notes. The darker the roast, the more sugar is converted into something else, which means less perceived sweetness and more bitterness. It is worth saying that the sugar content of coffee is so low that it sits below the detection threshold of human taste buds. Even so, caramelising those sugars creates new aromas that register as pleasantly sweet.
The process is delicate and needs precision. Roast too hard and the coffee goes flat and bitter. Roast too gently and it can come out too acidic, which also changes how sweet it seems. That is why a roaster’s skill decides the balance between bitterness, acidity and that subtle sweetness.
How perception shapes the impression of sweetness
The sense of sweetness can also come from aromas we associate with sweet food, vanilla or caramel among them. Coffees with natural vanilla notes or floral aromas therefore seem sweeter, even with no sugar in them. Coffees with a creamy texture, such as an espresso with a well built crema, can feel softer and more comfortable, and the mind reads that as sweetness too. Texture, smoothness and weight on the tongue matter just as much in building the whole impression.
Adding milk or a plant-based drink also shifts the profile a long way and makes the coffee sweeter without any sugar. Milk neutralises acidity and pushes the sweetness forward, which makes the drink feel more harmonious. Plant-based alternatives such as oat or almond drinks carry their own natural sweetness and can underline those notes further.
How to choose a coffee with a sweet profile
A few things are worth checking. A light roast keeps more of the natural aromas and a gentle acidity, and it holds on to the fruit notes that create the impression of sweetness. Beans from Ethiopia, Rwanda or Panama often carry fruit and floral notes we associate with natural sweetness. Processing counts as well: dry processing, where the cherries dry with the beans inside them, intensifies the fruit notes and lifts perceived sweetness.
Brew method matters too. A pour-over or a Chemex can pull out the subtle, fruity side of a coffee, which amplifies the sweet impression. So do the brew ratio, the water temperature and the extraction time. Brewing precisely is what lets the natural character of a coffee, sweetness included, come through.
Sweetness in coffee, seen properly
Coffee is not sweet in the way sugar or honey is sweet. The impression of sweetness comes from its aroma profile, its texture and the subtle interactions between our senses. It is a neat example of the brain interpreting flavour and aroma and building something particular out of them in every cup. Paying attention to the beans you buy, the way you brew and what you actually taste is how you get at all of it. So next time you sit down with a cup, it is worth asking what is really making it good.
