I'd like to introduce you to the Compak K-10 Doserless Conical Burr grinder. This model is a doserless version of Compak’s popular WBC (World Barista Championship) K-10 grinder. The K-10 doserless Conical Burr grinder, is extremely well built and very cost effective, when compared to other conical burr doserless grinders available on the market.
Conical burr grinders have a cone-shaped burr, at the base of the grinder, which rotates against a top burr. With the K-10 Doserless, coffee is gravity fed into the conical burrs. In contrast to flat burr grinders, which crush the coffee before cutting it down to size, conical burr grinders, such as the K-10 Doserless, gradually grinds the beans down until the proper grind fineness level has been achieved. Additionally, the K-10's unique burr is long and shaped vertically, to give it a large surface area for high-volume grinding.
One of the main differences between flat and conical burr grinders is the path the bean takes as it is ground. With flat burrs, the beans have to go down then change direction, in order to go between the flat burrs. With conical burrs the bean takes a direct path downward. I have included photos so you can see the difference between flat and conical burrs. The conical burrs are on the left and the flat burrs on the right
Since the conical burrs have a larger surface area, they are able to operate at a much slower speed than flat burr grinders. A flat burr grinder will normally run at about 1400 rotations per minute (RPM), where as a conical burr will operate at 400 RPM, or less. The Compak K-10 doserless grinder actually operates at 350 RPM. Operating at a lower speed allows conical burr grinders to generate a lot less friction and, therefore, much less heat—which helps to preserve the flavor and aroma of your coffee. Conical burr grinders are known for delivering a consistent grind, with a more uniform shape. Interestingly enough when you look at the coffee grounds, they have a noticeable fluffier look to them. There have actually been studies done, using electron microscopes that show the grind particles from the conical burr grinder to have a much rounder shape compared to coffee using a flat burr grinder. There also is a marked difference in uniformity of the shapes between the two types of grinders when analyzed by an electron microscope.
The resulting espresso shots also seem to have longer flow rates before going blond. Because of the grind quality and consistency, you'll find that it will be much easier to dial in your espresso machine for that perfect shot.
The bottom line is when you use a temperature-stable espresso machine, for instance one of the Dalla Corte units, and a conical burr grinder, like the Compak K-10, espresso quality and integrity will show a marked improvement. The complexity and clarity of the coffee flavor profile will be more noticeable.
I had a customer who is an amateur wine maker, and a chemical engineer; he also makes custom wood furniture. This customer is an educated complex man with a great palette. He had bought one machine after another and finally was happy with a double boiler PID controlled espresso machine the Expobar Brewtus IV. We had many conversations and discussed the many variables, involved in making a great shot in detail. He was always a little disappointed in the shot he produced, even though he owned a good flat burr grinder. He did not think the grinder was the problem. I knew the grinder would make a difference especially to someone like him, with such a great palette. Finally I convinced him and he purchased a Compak conical burr grinder. Upon receiving the grinder, he called me with an update and said “Nirvana! Nirvana!” He finally had made a shot that was even better than he had hoped for.
Initially I was, like him, a bit unsure if a conical burr grinder could really make a difference. This customer is proof a conical burr grinder is a sound investment.
Consider introducing or upgrading to a conical burr grinder, the K-10 Doserless model specifically, if you wish to improve the quality of your coffee.