Guide to coffee grinding
Why is the thickness of the grind we use to prepare coffee so important?
In this article we provide clarity to understand the role that grinding has in achieving an excellent taste of our coffee or, on the contrary, wasting the good work done throughout the value chain from the collection of the bean at its origin.
- Guide to coffee grinding and Burr Coffee Grinders Product
First of all, so that we have an overview of all the variables that can influence the final result of our drink (which we will explain in future articles), we leave you a brief outline below:
Coffee bean collection method → Processing method → Blend (mixture of different beans) / single origin → Roasting → Packaging → Time between roasting and consumption → Recipe (amount of water vs coffee) → Water hardness → Degree of grinding → Preparation method → Water temperature → Turbulence → Infusion time → Time between grinding and consumption .
What is a grind grade?
With degree of grinding we refer to the thickness of our ground coffee, for which we have had to select the point of grinding of the coffee in our grinder.
Ok, and why do we grind? Let's imagine a coffee bean already roasted. This contains many properties inside wanting to get out. What do we do to extract them? Mix the grain with water. But will I get it to dissolve by mixing the whole grains with very hot water and stirring it like there is no tomorrow? Obviously, the infusion that we will achieve will be very small. It is for this reason that we require grinding the coffee beans.
If we leave the rest of the variables that influence the final result of the drink constant and we only play with adjusting the coffee grind, we will be able to dissolve more properties of our coffee, the finer this grind is. Why? It is very simple. Let's imagine ourselves on the beach and, why not, enjoying a good coffee. From our umbrella we see how the children play with the watering can, pouring water on the fine sand. This water slowly seeps through and is completely absorbed by the sand. There is a lot of contact surface of the water with the sand, since being fine particles they come into contact with the water a lot. If we think of a coffee grind as fine as sand, it is easy to visualize that the water will carry many more properties of the coffee. Quite the opposite occurs with a coarser grind. Here we can establish the analogy with a pebble beach. If we water these stones with the watering can, the water filters very quickly and barely comes into contact with them, so we would drag less properties of our coffee.
Types of coffee grinding according to type of coffee maker
How to grind coffee for coffee machine?
What is the optimal grind? As with so many things in life, the answer is "it depends." Taking into account that our coffee is specialty and a medium or light roast has been applied, that is, we have the guarantee that the duties have been done in the steps prior to grinding, we can go for our goal in the preparation: " extract the sweetest possible point " to the coffee.
And here it is not only the grinding that intervenes, but also the contact time of the water with the coffee , the water temperature , the turbulence or pressure applied to it and the amount of coffee per water . Taking into account that we leave these last factors constant, we have to try coffee with a degree of grinding as a starting point.
If the result is a salty or acid taste, it means that we have solubilized a small amount of coffee. That is, we need a finer grinding point. When this occurs, we speak of " sub-extraction ". Suppose we adjust several degrees for a fine grind and, as a result, we get a bitter or burnt taste. In this case, we refer to this situation as “ over-extraction ”, and we have to adjust the coffee grind to a greater thickness. The flavors that result as the coffee is solubilizing appear in the following order: salty → acid → sweet → bitter .
Another factor that can lead to unpleasant flavors is that some beans are ground finer than others, which will lead to “under-extraction” in some parts of the coffee and “over-extraction” in others, at the same time in the coffee. same drink. To avoid this, it is essential to have a good grinder, with the strawberries slightly worn and well placed.
Types of grinding and coffee grinders
We can classify the grinding into three types according to its thickness, each of which is more appropriate for a preparation method:
- Coarse grinding : it is the most used for coffee tastings or other preparation methods such as the French press, the metal filter or cold brew.
- Medium Grind - Widely used for manual drip infusion methods with paper filter.
- Fine grinding : it is used for the most common infusion methods, in which pressure is used: espresso from espréss machines, Italian mocha and aeropress.
Regarding the types of grinders to carry out the grinding operation of roasted coffee, we find:
- Electric blade mill : the most used in homes. The blades cut the coffee and the biggest problem is the lack of homogeneity in the size of the coffee particles, precisely one of the main objectives of a good grind.
- Manual mill for flat strawberries : it is the most popular and classic system. To regulate the grinding to a greater or lesser thickness we move a kind of axis. The coffee maker grinds and stores a dose that you have regulated. It is useful if you have a lot of concentrated work in a short time in a cafeteria, since it allows you to extract the stored dose of coffee in just 1 second.
- Conical Strawberry Manual Mill : The ability to fine-tune the grind with this mill is much higher, since moving the axis one hairline means changing the grind 10 times less than in the flat milling cutter. Therefore, the sensitivity of the change in thickness of the grind to shaft movements in a tapered cutter is much lower.
- Automatic mill with flat strawberries : the dose depends on the time you are grinding. Grind the dose instantly. You never know how many grams are going to come out because it depends on two variables: degree of grinding and grinding time.
Commercial Coffee Grinding
Grinding in commercial coffee
Obviously, when we are not talking about specialty coffee, the meticulousness and search for excellence in the degree of grinding (as in any of the other variables that, for simplicity, we have left constant in this post) does not make much difference in taste end of coffee.
The reason is very simple. The beans have been massively picked, both the immature green and the overripe black, and to camouflage their faulty flavors a very high roast is applied to the coffee. This causes us to lose our ability to extract the magical "sweet spot" in preparation. In the first place, because the bean was not harvested at its optimum point to offer this flavor and, even if it had been, it would have been burned by cooking the coffee at high temperatures with the high roast. The resulting flavor of these coffees is bitter or even burnt.
How do I adjust the grinder on my super-automatic coffee machine?
In JURA super-automatic coffee machines , in a similar way to other brands, we have a wheel that allows us to adjust the coffee grind to our liking. At the push of a button on the JURA machine, we comply with rule # 1 of coffee: “ground at the moment”, since coffee ground the day before has lost most of its aromatic and flavor properties.
With this super- automatic machine we achieve an exceptional result for a specialty coffee by automating the entire preparation process, without the need for an expert barista who takes into account the perfect harmony between all these variables: Degree of grinding → Preparation method → Temperature of the water → Turbulence → Infusion time → Time between grinding and consumption
Furthermore, JURA has completely perfected the brewing process for Ristretto and Espresso . A unique innovation guarantees a professional grinding result that increases aroma by 12.2%, simulating the result that a professional barista would achieve in a specialty coffee shop with an espresso machine.
