An ideal coffee grinder produces ground particles that are a consistent and correct size. By that we mean that the size of the ground coffee particles should match the coarseness setting of the grinder, fine or not. The size of the ground coffee produced should also be appropriate for the intended brewing method, as described in the product manual.
To test each grinder for our coffee grinder reviews, we first hand wash and dry all of the parts recommended by the manufacturer. Then, we set each machine to the appropriate grinding level for filter coffee or automatic coffee makers (again, as specified in the manual). Sometimes, specific instructions are missing from the manual. In this case, we select the medium coarseness setting for grinding coffee, then increase it by one coarser setting (from a fine grind, such as an espresso grind, to a coarse grind). For example, if a grinder has a total of 16 coarse grind settings (assuming 16 is the coarsest grind option and 1 is fine), we set it to coarse setting 9.
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Next, we weigh 10 grams of whole coffee beans to grind. By default, our test beans are Kirkland Colombian Casserole. These are the same beans we use for our coffee machine tests. (No judgments, please.) When you grind as much coffee and espresso as we do, it pays to be frugal.
Next, we run our sample beans through the grinder. We also note how long it takes the grinder to grind the coffee beans. Then, we carefully collect the coffee grounds and sift them for 60 seconds using a double screen sieve. For this, we use the Kruve Sifter System. Our original Kruve Two unit came with two mesh screens of different apertures (800 and 400 microns). This step allows us to measure the grind size and grind consistency of our sample. The Kruve base has now replaced the Kruve Two and offers five mesh screens (300, 500, 800, 1,100 and 1,400 microns).
We used a Kruve coffee sieve system to confirm the consistency of the grind.
A superior electric or hand grinder produces ground coffee, preferably with stainless steel blades, that is usually between 400 and 800 microns in particle size (at our chosen grind settings). Finally, we weigh the ground coffee that collects between the two screens (800 microns on top, 400 microns on the bottom).
A bad grinder will grind particles of varying sizes, from large to small. Blade grinders are notorious for this problem. Unlike a blade coffee grinder, a grinder with steel or ceramic burrs will usually produce a much more consistent grind.
The Oxo coffee grinder weighs the coffee grounds for extra precision
View all photosIn addition, we grind at least two more times. From there we can establish an average optimal yield for each grinder.
