The humble coffee grinder plays a huge part in delivering a quality cup of coffee, but how does a coffee grinder work? Not all grinders work in the same way, and some so-called grinders don’t actually grind at all. Make sure you read this article before buying a coffee grinder.
Two types of coffee grinder
If you are new to the world of coffee grinders, the first thing to understand is that there are two basic types of grinding mechanisms: blade and burr.
Few experienced baristas will use a blade grinder by choice. A blade grinder doesn’t really ‘grind’ at all. Instead, it uses a pair of sharp, rotating propellors to chop the coffee beans into bits. The longer the blades spin, the finer the coffee, and you can usually either manually pulse the machine or use a time preset. Either way, blade grinders will spit out uneven grounds which makes it difficult to control the fineness of your grind. Blade grinders also get hot and generate a lot of static. This impairs the flavour of your coffee and also makes your grinder harder to clean because the grounds stick to the blades.
In an ideal world, most baristas would opt for a burr grinder. These too come in two types, and here the difference is more subtle. While both types use serrated burrs to crush coffee beans, the answer to the question, ‘How does a coffee grinder work?’ depends on the specific mechanism involved.
How does a coffee grinder work? Flat burr grinders
Flat burr grinders work mainly through centrifugal force. For those of you who remember your school physics lessons, this is a force which ‘flees’ from the centre to the outside of a spinning circle.
In a flat burr grinder, the circle in question is a spinning disc. The coffee beans are fed into the centre of the mechanism between the spinning disc and its stationary partner. The beans are then crushed and the grounds are flung towards two side channels which lead to your container or portafilter.
To generate enough force, flat burr grinders have to spin very fast which generates a fair bit of heat and static. However, the mechanism is designed to produce a very even grind.
How does a coffee grinder work? Conical burr grinders
You may have forgotten all about centrifugal force, but chances are you remember gravity. Burr grinders are designed to work with gravity, both in terms of the grinding and the channeling of grounds. Instead of spinning discs, a conical burr grinder contains a slowly rotating steel or ceramic cone within a stationary ring. Beans fall into the mechanism, and the resultant grounds fall through into the container or portafilter.
Burr grinders therefore provide a cooler environment, which helps to preserve flavour. There is a downside though: burr grinders produce a slightly less even grind.
Adjusting the size of your grind
How does a coffee grinder work in terms of producing the right grind size for your needs? With burr grinders, the gap between the discs (or cone and ring) determine the fineness of the grind. In modern electric grinders, you have the ability to fine-tune this spacing to get the exact grind size you want.
Advanced grinder features
One of the most useful developments for commercial coffee outlets has been grind-by-weight technology, as epitomised by the Mahlkonig E65 GBW grinder.
Browse our range of quality coffee grinders
If you’re ready to explore the wonderful world of grinders, visit our dedicated page of quality coffee grinders. If you have any further questions, please don’t hesitate to get in touch.