Rather than developing techniques that are suited to our coffee and fit with our grinders, we all too often pass the buck: we complain and worse—we grossly abuse what we have and still expect it to perform well. Seeing as this kind of interaction hasn’t worked too well with the humans among whom you work everyday, it’s not likely to cut it with your mechanical companions either.
In researching this article, I found some surprising facts and disturbing trends. Most baristas don’t clean their grinders. They don’t change their burrs, they wail on the doser arms and generally abuse the grinder. Most shops run grinders way beyond their intended capacity. Many put more thought, maintenance and money into the chairs in the dining room. Passion for good coffee needs to be tempered with knowledge and discipline with the equipment. Just in case those of you out there in the top 10 percent of espresso land think I am not talking to you, think again—you are some of the worst abusers I have seen, in part, because you should know better!
How well you operate your grinder, how well you work it, or it works you, will affect not only the particle size of the grind, but also the shape of the particles, the speed of grinding, the amount of heat transferred, the static imparted, and the clumping of granules. It will affect the life of the burr set, the life of the grinder as a whole, as well as the life of your arm, wrist and shoulder. In turn, these affect the quality of the coffee you produce and the ease with which it is made.
Espresso grinders are relatively simple pieces of equipment. Their components can be divided into five basic parts: hopper, grind control, doser, body, and motor. We will take a look at each part and as you learn more about what really gets your grinder going, you’ll find the foundation you need to build a partnership that’s going to last.
Hey Man, Nice Hopper!
All hoppers are designed with the idea of providing an even flow of beans to the burr set, with as little vibration and separation of blends as possible. Most hoppers are a combination of polycarbonate, plastic and metal. In the case of removable funnel shaped hoppers there is generally a slide gate at the base, and often a catch to ensure the hopper stays in place. Non-removable hoppers vary but often have a removable liner. The materials used to construct the hopper are important to consider when creating your maintenance program. Not all materials used are dishwasher friendly; watch out for lower grade metal slide gates, soft plastics not suited for chemical based sanitizers, and joints that will separate with the expanding and contracting that takes place during the washing of their various components.
There are three main limitations to the current popular hopper designs. First is the admittance of light and air. This is more of an issue with blends that need a longer resting time, as they will already be well on the way to degradation when they are placed into the hopper. Clear glass hoppers are not advisable, as they reflect and can, in some cases, magnify harmful UV rays onto the coffee. For those bars with direct sunlight in the grinder area, or strong overhead lighting, it is recommended you wrap the hopper with UVblocking tinted plastic film like the kind used for car windows. In a pinch, you can even use brown paper.
When it comes to air mixing with your beans there are few practical solutions. This is largely because of the second limitation of the main hopper designs: the rate and feed pressure of the beans as they enter into the burr set. As a hopper empties, the weight of the coffee bearing down on the entrance to the burrs changes, and this in turn can affect the rate of grind, as well as the shape and mixture (fine to not as fine) of grounds coming out. Each grinder has a sweet spot for rate of grind, and this will change with burr wear. For best results, fill the hopper up and keep it full, stopping to replenish in between rushes. A hopper design that would keep out air would need to be reanalyzed from the ground up, and would likely involve pre-measuring a dose by weight or volume.
The third limitation of virtually any hopper is simply due to its interactive role with the coffee. Crud inevitably builds up and must be cleaned out. The main problem areas are where the hopper attaches to the grinder just above the burr set, at the slide gate, and where the walls start to angle or funnel. If the inside of the hopper is not kept clean, oils will build up, imparting old coffee flavors and creating a sticking problem. In extreme cases, this can lead to an uneven flow of beans causing blends with many varying densities and sizes to fall apart.
For the ultimate sexy custom hopper, consider a stainless steel spun metal hopper and lid with sight window from a company like Toledo Metal Spinning.
Maintenance of the hopper is fairly straightforward: wash daily with a mild soap to remove oils and dry well, watching for signs of cracking and wear.
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