1. The type of Grinder (Blade/Burr): The very first thing that you must consider is the type of grinder. The types vary in terms of utility. For example, a blade grinder is useful for quick and effortless grinding, whereas the Burr grinder provides a more customizable, albeit time consuming experience. Both have their benefits, but you as the buyer, must consider this before purchase.
Burr grinders provide consistency and retains most of the flavor of the coffee beans, but are usually not very portable and are very expensive, which brings us to the next point:
2. Price point: Professional grade coffee grinders can go up to $500 or more, whereas a manual grinder or an electric grinder may cost only up to $15. The price range is one of the most important determinant factors regarding quality and must be considered before purchase.
There are machines that are cheap and great, but if one is looking for the best coffee machine, spending upwards of $100 becomes necessary.
3. Type of Burr: This is only for people who want to purchase Burr grinders. Burr grinders have two types of Burrs, that is, Conical and Flat. Flat Burrs are usually best for a really fine grind, which is used for preparing espressos and Turkish coffee. Whereas Conical Burrs are used to make an all-round, consistent coffee experience on different ranges of brewing methods.
The material of the Burr is also very important. Ceramic Burrs usually do not transfer any heat on the beans, as that can deter the flavor. Metallic or steel burrs, being conductive, can sometimes transfer heat onto the beans.
4. Step/Stepless grinders: This, again, is applicable to Burr grinders only. The level of adjustment that a coffee machine offers is an important factor to consider, as it is the primary determinant of the coarseness and texture of your grind.
Stepless grinders have near infinite adjustment of the coarseness/fineness of coffee as instead of having levels, they have a knob that turns infinitely.
Step grinders on the other hand, provide set levels of grinds that can be adjusted to get a more consistent experience.
5. Size of the Burr: larger burrs usually have more flavorful coffee, as there is a lot more surface area on the burrs and heat retention is never a problem. Whereas, if a burr is too small, it may heat up and spoil the coffee beans’ flavor. So, you must have a cool down period in case of smaller burrs so the burr comes back to room temperature.
6. Timed or weight based grinding: Some machines offer weight based grinding, where the beans are measured on a scale and put into the machine. The machine then grinds them accordingly to get the required grind size.
Time based grinding on the other hand, grinds a large amount of beans to a set duration of time to obtain the amount of coffee grinds required.
7. Position of blades: For blade grinders, one must always ensure that the blades are placed low in the machine. This is because if the blades were to be placed high up, a lot of beans would stay under the blade and not be ground up.