The main difference between the various coffee grinders lies in the technology of their conical burrs (for large consumption) and flat burrs for limited consumption and their number of rotations per minute.
The life duration of burrs also depends on the quality of the material they are made of, the working precision and the kind of thermic treatment they undergo.
Burrs are available from LF store are strictly Made in Italy. Although you will also find on the market low cost Chinese manufactured burrs.
It is important to know that the friction between the burrs and coffee beans produces heat which will cause it to wear out with time (increase of friction/heat). In addition the grease contained in the coffee sticks to the burr’s teeth increasing the friction and changing the resulting grind.
Important: the temperature of ground coffee cannot exceed 50°C otherwise the aromas evaporate before the extraction and there is the risk of “burning” the coffee (even more so for espresso coffee!).
Check both grind measure (if it changes with time, for instance) and temperature.
Clean your coffee grinder on a regular basis (every 24/48 h according to the amount of ground coffee).
Specific products are available for the cleaning of burrs.
When you notice that the ground coffee temperatures increase despite the burrs being cleaned or the grind is not perfect, it means that you have to replace your burrs.
Remember that for espresso coffee you have to use from 6.5 to 7.5 g of ground coffee.
Dosing is important for a good result and it has to be always within the above mentioned limits. Dosing can be made manually using measuring scoops and precision scales but it is advisable to use coffee grinders which, once they have been calibrated, are independently set to the right dosage.
The information and the images in this article were taken for the book La filiera del caffè espresso published by Bazzara.
For professionals and for espresso coffee lovers we suggest reading the articles contained in the section called "Coffee". Also watch the videos on the correct use of equipment in coffee making and on latte art in the section "Video".