How do you get the best flavor out of coffee thanks to math?

Despite popular belief, espresso coffee is not called that because it is served quickly or prepared quickly. Actually espresso is the past participle from the word “esprimere”Thus, which in Italian means pressure, refers to the process by which the coffee is made, not the type of drink.

Espresso is made by first grinding roasted coffee beans. then Hot water and high pressureit is forced through a bed of coffee beans and the soluble content of the coffee beans is dissolved in water (extraction) to produce espresso.

In 2018 it was published study Which showed that coffee beans that were ground more than normal resulted in weaker espresso. This counterintuitive experimental finding makes sense if, for some reason, regions exist within the coffee bed. Where less or no coffee is extracted. This uneven extraction becomes more noticeable as the coffee becomes finer.

Now, a team from the University of Huddersfield has published a dossier New study In fluid physics, where the role of extraction varies coffee using a simple mathematical model. They divided the coffee into two regions to examine whether the uneven flow produced a weaker espresso.

One region of the system contained more pressurized coffee than the other, which caused an initial variation in flow resistance with water flow More quickly through the most compacted beans. Coffee extraction also reduces flow resistance, with coffee beans losing 20-25% of their mass during the process.

Our model shows that flow and withdrawal broadened the initial flow contrast between the two regions, and this, in turn, increased Reduces resistance and generates more flow – explains the study leader, Guillermo Lee -. This effect appears to be permanent, and we will not see the experimentally observed decrease in extraction with decreasing grind size until all of the soluble coffee in one area has been extracted.”

The researchers were surprised to find that the model always predicted uneven flow in different parts of the coffee bed. Basically there Fine grinding point allows for this The water that passes through the ground coffee is infused with all the properties of the fruit but without being abused to produce an overly bitter beverage.

“This is important because the flavor of the coffee depends on the level of extraction,” Lee adds. Very little extraction and the flavor of the coffee is what connoisseurs call “lag,” or as I put it: smokey water. Too much extraction and the coffee tastes very bitter. These results indicate that even if the total extraction appears to be at the correct level, It could be due to a mixture of bitter and unsophisticated coffee“.

Understanding the origin of uneven extraction and avoiding or preventing it can allow for better brewing and significant financial savings by using coffee more efficiently.

Our next step is to make the model Be more realistic to see if we can get the information More details about this confusing phenomenon – I conclude -. Once this is achieved, we can begin to consider whether changes can be made to the way espresso is made to reduce the amount of uneven extraction.”

The good thing about this science experiment is that we can do it at home: just try different types of grinding and pressing, if we use an Italian coffee maker for example, Evaluate whether we are getting “smoked water” or bitter coffee. Although it is also a matter of taste.