The chemistry of perfect coffee

When evaluating coffee espresso we look a lot at taste and aroma, as well as other parameters such as foam. coffee foam it is something essential, even when we are talking about a moment. But why? It is clear that this is not only an aesthetic problem, but also something that makes the consumption of the drink much more enjoyable. And, of course, there are a lot of chemicals in its preparation.

Although it should be clear that we mean coffee foam. It’s also possible whip milk what is poured on it, but that’s another matter.

Such is its importance that many scientists have already begun to study its properties, how to obtain espresso ideal for better understanding the process that leads to foaming in other foods and drinks. The main conclusion of all these studies is that the key to coffee foam is in carbon dioxide. But other interesting data is also extracted.

What is coffee foam?

Before talking about one form or another, it is worth remembering what coffee foam is. Foam mainly consists of coarse dispersion of gas bubbles in a continuous liquid phase.

in the case of coffee espressothe gas phase mainly consists of carbon dioxide, which is formed during coffee roasting and is trapped within its cellular structure. On the other hand, the continuous phase is emulsion formed by microscopic drops of oil in an aqueous solution of various solutessuch as sugars, acids, proteinaceous material and caffeine. In addition, the foam may contain solid fragments of the cell wall of the coffee beans.

Finally, it is important to keep in mind that for coffee to be considered espresso, the foam must at least 10% of the total volume drink

What happens during roasting?

As we have already seen, in the case espresso in coffee foam comes from carbon dioxide, which is formed during roasting.

This occurs when coffee beans are exposed to hot flue gases or air during temperature above 200º C. At this point, the characteristic smell, taste and aroma of coffee develop. But not only that. A number of gases are also formed, of which 87% is made up of carbon dioxide.

We already have the necessary gas to create coffee foam. However, its stabilization requires the presence surfactants. They can be added artificially, but in coffee espresso No need. The problem is that it is not entirely clear what these natural surfactants are. The role of some lipids and proteins at the moment, but it is impossible to determine exactly which of them are responsible for stabilizing the coffee foam.

So far, we have the origin of carbon dioxide and the role of unknown substances acting as surfactants. But we still need to know how this carbon dioxide is released. It is formed during roasting, but in order for coffee foam to form, it must be released, and this is where it comes into play. grinding

It destroys the cell structure of pre-roasted coffee beans. It can be seen that if this is done before the formation of particles with a size of no more than 500 μm, 70% carbon dioxide. Here another essential factor comes into play if we are to obtain espresso perfect time. And the fact is that if too much time passes after grinding, you will not get suitable foam.

Therefore, it needs to be done maximum 30 minutes before making coffee. That is why lovers of this drink have their own coffee grinders. It makes no sense to compare freshly ground coffee and bought ready-to-drink coffee.

Benefits of coffee foam

The coffee froth makes it much more appealing, but has other benefits as well. For example, well cured foam. retains aromatic compounds so drink a lot tastier.

Also, prevents the coffee from cooling too quickly. True, there are people who prefer to drink it cold, but as a rule, it is much more appetizing and tastier when still hot. True, now that summer is coming in the northern hemisphere, it is less appetizing, but that’s what ice is for.

In short, coffee foam is an art, and as is always the case with art, there is a lot of chemistry behind it. Because science is everywhere, from the colors of the most important artists in history to espresso which helps you enter the world in the morning.