Bitterness is the peculiar sensory characteristic of coffee. But why is coffee bitter and why do we like this typically unpleasant taste in our favorite drink?
We should not like the coffee. In nature, the ability to distinguish the bitter taste, in the course of evolution, has protected us from potentially toxic and poisonous or otherwise harmful substances.
Why then the bitterness of espresso is irresistible? A study investigating the relationship between genetics, sensitivity to bitterness and tendency to consume coffee, has shown that people most sensitive to the bitter taste of caffeine are also those who drink more coffee.
It seems that this predisposition derives from experiences of positive reinforcement: we learn to associate caffeine with positive effects of stimulation and well-being, and these organism responses make us even more receptive to its characteristic aroma.
Coffee already contains sugar!
Not everyone knows that Arabica is the most aromatic and less bitter species because it naturally contains 8% sugar, while Robusta contains 5%.
To confirm that the coffee contains sugar: the change in the color of the bean from green to brownish-olive when roasting is due precisely to the caramelization of sugars. It is in this delicate phase that the percentage of sugar passes from 10% to 2% and on the surface of the bean appears a brown colored oil, which determines the characteristic aftertaste of chocolate and a slight loss of caffeine.
The presence of sugar is so reduced that coffee is to be considered in all respects a low-calorie drink. Just think that a medium cup has only 2.4 calories.
Coffee is also rich in antioxidant polyphenols, with essential minerals such as iron, calcium, magnesium, potassium and phosphorus. Recent studies show that all the nutrients in coffee, including sugar, contribute to the well-being of the body.
So why do we add sugar in coffee?
It is an eternal and old diatribe among coffee lovers: coffee is strictly bitter or can it be sweetened?
The schools of thought are many, as well as many are legends. Both factions appeal to taste, to tradition, to the idea that “a true connoisseur drinks coffee like this”.
In reality, those who are used to drinking sweetened coffee usually have an unpleasant impression when they taste a bitter for the first time. Conversely, those who drink or those who are used to drinking bitter coffee will never go back, and indeed tend to have the impression that sugar in coffee alters the real flavor and the characteristic aftertaste.
In Italy, the two factions are so fierce in defending the superiority of bitter or sweetened coffee, not least because in Italy the coffee is not simply one of the many drinks: coffee is a social and cultural issue, it is the symbol of a society with slow but profitable rhythms, which rather than get depressed or give in to melancholy, you make a nice coffee that drives away all the problems in one shot!
But how much sugar do we put in espresso?
An experiment based on the “nudge” theory by Richard Thaler (Nobel Prize for Economics 2017) has shown that the unit of measure for the use of sugar in packet is not the quantity of product but the packet itself.
Only that up to 20 years ago a packet of sugar contained 7gr. Then over the years, the greater attention to food diets and wholesomeness, has reduced the amount of sugar contained in the packets up to 3-4gr.
The packet often leads to partial use of the sugar content (and the surplus becomes food waste). On the other hand, there are cases in which instead it leads to consuming more sugar than necessary.
What is the ratio between sugar and coffee in the cup?
An espresso is 25/30ml. So on 25gr, how much is water and how many substances are extracted from coffee (and therefore true coffee)? The answer is around 8-10%.
Therefore it means that on 25gr of drink we find scarcely 2.5gr of substances dissolved from the coffee bean. To which then add at least another 4gr of sugar.
Attention then not so much to use, as to the abuse of sugar in coffee!
However, experts advise enjoying coffee without adding sugar.
Is sugar in coffee really that bad?
Coffee isn’t made in minutes. It’s made in days, months, even years of hard work.
Every step of the supply chain is focused on bringing out the best possible flavours in a coffee.
What’s more, those flavors are unique. They’re created by the coffee varietal, the soil it was planted in, the use of (organic or not) fertilizers, the amount of shade, the altitude, the processing method and more.
Then the roaster chooses a roast profile that will emphasize the best flavors in those beans.
The barista develops a recipe that highlights those notes even further.
Adding sugar in coffee, it doesn’t just make it sweeter.
Caffeine, sugar and water interact at a molecular level to block the bitter taste that some coffee drinkers dislike. A study showed that sugar in coffee reduces the drink’s bitterness by changing its fundamental chemistry.
The flavor balance changes. A perfect coffee, once you’ve added sugar to it, is not longer the same drink.
Sugar vs bad coffee
Many believe that sugar in coffee can correct and make more pleasant not good or done-bad coffee. In reality, it is not like that at all!
Sugar is a flavour enhancer (like salt or pepper) and has the extraordinary skill to increase the aromatic persistence (attention: both for good and bad coffees), to improve the spherical perception and the body and to depress the bitterness, also allowing those who are particularly sensitive to this flavor to concentrate more on flavorings and therefore to increase the pleasure they derive from the act of consumption (provided that the coffee is good).
Which means: a modest amount of sugar in coffee can enhance its natural flavor but at the same time it can accentuate, certainly not covering or improving, defects when coffee is not good.
We talk about sugar, not sweeteners, which do not have the same sensory virtues of sugar and often increase bitterness or otherwise leave strange aftertastes.
Taste is in the mind of the consumer
Coffee is a science and art at once.
Coffee, like art or food or music is a preference. Some coffees are like the Mona Lisa, universally beautiful. And some are like Modigliani’s women, you need to have some understanding of the subject matter to appreciate them.
Again, like art, coffee has a few universally appreciated attributes. But at the end it’s up to individual to choose what coffee they like to consume.
Sugar in coffee shaming: it’s not helpful!
Maybe most people have not experienced naturally sweet, clean coffees that have been properly prepared. Their only frame of reference is that coffee needs sugar.
That doesn’t mean we can’t politely suggest sugar-loving coffee enthusiasts taste the coffee before deciding whether or not to add sugar. We try food before adding salt, so why not adopt the same policy?
Some will always put sugar in coffee and there’s no changing that behavior. However, many more will find themselves putting less sugar in their drinks over time… once they no longer need to put sugar in coffee.
The “baristocrats” feel a little pinch in their hearts when you add sugar in coffee.
But there’s no point in judging anyone for how they enjoy their coffee.
We all appreciate coffee in different ways.
Tastes are tastes and by definition are deeply subjective.
But it is equally true that not all coffees and blends are the same.
The evolved espresso
We can not ignore the fact that in recent decades the espresso has profoundly evolved and continues to change.
In the past, in blends it was common to find a strong roasting profile that gave birth to a rather pronounced bitter sensation. This procedure was functional to obtain an important and intense drink of the body but, in truth, it often also served to hide the defects that would emerge from a more balanced and clear roasting.
Today the roasting profile is “softening”, the average quality of the product to be processed is better and therefore, logically, the roasting will have to bring greater respect to a more prized, more complex and more aromatic coffee.
The same ritual of the espresso is evolving and what was only a habit, is becoming a real hedonistic rite, varied and very personal, looking for the pure pleasure of drinking an espresso. After all, espresso does not feed and is not a necessary food, so it must satisfy everyone’s personal tastes.
The sensory analysis does not lie
However, if we speak of sensory analysis, of objective and non-subjective evaluation, of objective determination of the quality of a coffee, of an origin or a blend extracted in espresso, then things change.
The aromatic profile in the cup of an espresso should be rather large and complex. There is also talk of a higher complexity than the great red wines for the presence of over 2000 different aromatic molecules. Among these, there will be some in concentration to be perceived in a clear and dominant but, possibly and probably, there will be others in much lower concentration, perhaps very low, and therefore much more difficult to perceive.
In the ambit of the aromatic molecules very concentrated in just 25ml of an espresso, you could have wonderful sensations, soft, mellow and very amiable but also small defects, such as to drastically penalize the quality of the drink in question.
The typical roasting for Italian espresso tends to generate a perceptible bitter sensation, and inevitable for the caramelization of sugars, in turn accentuated by the bitterness of the caffeine present in the bean. This bitter note could “cover” and hide other sensations that may be milder and more delicate like those of wonderful aromas of flowers and/or fruits that the taster wants to grasp.
At the same time, the roasting may also bring out small defects and then it is mandatory to catch them, especially if you are doing sensory analysis.
For these reasons, tasting an espresso with or without sugar could give different results.
In the end “a spoonful of sugar” (just a little) is enough
just enough to balance the natural bitterness (mild and moderate) of the roasted coffee!