The grinding, or grain size of the coffee is a fundamental element in the preparation of a perfect cup of coffee. Many coffee enthusiasts consider this process a true ritual, in which art mixes with science; in fact, correct grinding can make the difference between a mediocre espresso and a drink with an exceptional taste.
In this article we will explore the importance of grinding coffee, the different types of grinding and how to obtain the best results for an unforgettable tasting. The granulometry directly affects the quality and flavor of the final drink, as it determines the extraction of the essential oils and soluble compounds present in the coffee beans.
The grinding of the coffee is important because it increases the surface area of the coffee in contact with the water, facilitating the extraction of the aromatic substances and allowing you to create a balanced cup of coffee. The fresh grinding of the coffee is also important to obtain a creamier and fuller-bodied drink: it must be adjusted based on the coffee preparation method, the type of coffee beans and roasting level.
How is coffee ground?
The coffee grinder is a very important piece of equipment inside the bar, often even more important than the espresso machine, which through a pair of grinders (conical or flat) allows you to chop the coffee beans into small particles.
By adjusting the grinding of the coffee, the distance between the grinders is increased or reduced: moving them closer will give you a finer grain size, moving them further away will result in a wider grain size.
Each grinder has its own system for regulating the distance of the grinders manually or electronically, usually numbers or circles of various sizes are indicated to facilitate the setting of the grinding.
How to adjust the coffee grinding?
To adjust the grinding of the coffee, it is necessary to choose the type of grinding based on the preparation method, adjust the coffee grinder according to the desired grinding, adjust the grind based on extraction time and extraction method and experiment with different grinds to find the perfect one for your personal taste.
Coffee grinding and the main types of extraction
Coffee grinding is an important factor in obtaining a quality drink. Here is the ideal grinding based on the main types of coffee extraction:
- Espresso: fine grinding to obtain a creamy and full-bodied drink.
- Moka: the ideal grind is medium-fine.
- French Press, Aeropress: the grind must be coarse to prevent the coffee from being too bitter.
- V60, Chemex: the grind must be medium-fine.
What if the grinding is incorrect?
Over-extraction and under-extraction are two problems that can occur during coffee extraction due to inadequate grinding.
over-extraction occurs when the coffee is extracted for more than 25-27 seconds and when the grain size is too fine. The result in the cup is certainly a bitter and astringent drink. To adjust over-extraction it is necessary to make changes to the coffee grind to make it coarser to reduce extraction times.
under-extraction occurs when all the aromatic potential is not extracted from the coffee: it happens when the grinding is too coarse and the result is a coffee that is not very full-bodied and lacking of positive aromas. To remedy under-extraction it is necessary to adjust the grinding of the coffee, make it finer and increase the extraction time.
Another crucial aspect is that of the freshness of the product. Ground coffee quickly begins to lose its aroma and flavor due to oxidation. To obtain a perfect cup it is advisable to grind the coffee at the moment. This way we don't lose aroma and taste.