What’s your favourite flavour? Back to the basics, the base five tastes we can perceive are: sweet, salty, sour, umami, and bitter.
My favourite is bitter. Why? And does that make me a psychopath, sadist, or narcissist? Maybe… according to those whose favourite flavours are bitter may be more likely to be psychopaths, according to a 2015 study.
The reason why it’s not the best flavour for most people is because of our instincts. We naturally perceive bitter as unpleasant as a defence mechanism to tell us that we shouldn’t be eating something, as it may be toxic— although that doesn’t mean all bitter is bad for us.
Liking bitterness is a learned behaviour. It is the most common reason kids reject food due to its taste. Think of the first time you (or anyone you know) tasted beer. This experience is usually met with disgust, in particular if you tried it at a young age when you hadn’t opened up to appreciating any bitter flavours yet. You accumulate a taste for bitter in things like beer and coffee over time, and associate it with the reward it is: a cool, carbonated alcoholic beverage, or a warm, full-bodied caffeinated drink. The “unpleasant” taste of bitterness only becomes appreciated in context of an ingredient or dish.
If you’re having a hard time thinking of deliciously bitter flavours, think: fresh grapefruit, citrus peel, coffee, green and black teas, dark chocolate, radicchio, endive, liquorice, red wine, hops, and unsurprisingly bitters (an alcoholic preparation usually concocted from citrus peels, herbs, and traditionally, the bark of a cinchona tree).
It’s the most sensitive of tastes.
We are so sensitive to bitterness that it needs to be used in perfect moderation, delicately balanced. Bittersweet chocolate is a classic example of bitter balancing a dish. If you use milk chocolate when making chocolate chip cookies, the final cookie could likely be overwhelmingly sweet as the dough mixture includes copious amounts of sugar in it too. By using bittersweet chocolate, usually a darker chocolate with less sugar and more cacao, you balance the sugary goodness of the cookie dough with the contrasted bitterness that highlights the cacao’s natural flavour. Not only in desserts, bitterness is vital to balancing flavour, especially in adding an exquisite depth to a dish.
That’s why with good espresso, there should be a well-balanced bitterness that compliments the other basic tastes of sweet, salty, and umami in harmony. Bitterness balanced well is like a tremolo on your tongue: it creates a juxtaposition of flavours. Its contrast is more powerful than any of our other five basic tastes. I like to think of it as tricking or confusing your taste buds.
It can also be a mouthfeel.
Tannins, common in teas, red wines, cacao, and of course coffee are familiar bitter-tasting compounds that make your mouth feel dry. There are many types of tannins, although they all typically create the same “dry” sensation in your mouth. It’s a sensation caused by the tannins binding to the proteins of your mouth, inhibiting your salivating functions, quite literally, making your mouth drier. When tasting coffee, we use the word astringent to describe the feeling of dryness that accompanies bitter flavours.
So what is bitter?
Bitter flavours are commonly toxic compounds to humans, and are predominantly found in plant matter. This is why it’s the taste most commonly perceived as unpleasant. Imagine you’ve discovered a new plant that looks like it could be nutritious, so you pick it up, taste it, and learn that it’s extremely bitter. It’s an immediate lesson not to consume this plant, reinforced by your instinct to dislike bitterness. Although bitter does commonly indicate toxicity, it doesn’t mean a substance is always toxic. The bitterness in coffee and cacao is attributed to each substance’s antioxidants. Antioxidants are nutritious compounds that inhibit oxidation in your body, preventing the potential damage of cells.
Bitter is everywhere, and is actually the most common flavour of all plant life. Next time you retract in disgust to a bitter vegetable, or underripe fruit, remember all bitterness isn’t bad. That being said, don’t think eating any plant that tastes bitter is a detox: it is quite likely it’s poisonous. I recommend sticking to bitter ingredients that we know won’t put you in hospital. Bitter is one of the most intense and delicate of the flavours at the same time, and can be appreciated in the most sophisticated of foods if balanced appropriately. Balancing bitterness in coffee works marvels for the mouthfeel and compliments our other perceived flavours.