by Pierce Jens, Technical Support

The amount of information that is at the tip of our fingers, thanks to the Internet, is a powerful asset. Unfortunately this power can be bad as well as good, for information can be skewed or misinterpreted and then shared. I wish to set straight some aspects of our grinders and troubleshooting info that I have seen misinterpreted by do-it-yourself-at-home grinder repair folks.
The calibration adjustment of each of our conical coffee grinders is in place for us to use at the factory during manufacturing. Each of the individual parts that compose any assembly, including our grinders, has a manufacturing tolerance- whether it be in millionths of a micrometer or in fractions of an inch, everything that is made will have slight variations in size. After assembling the grinder, we use the calibration adjustment to standardize the burr touch time of the unit, so as to ensure the proper range of grind size will come out when you adjust the grind between 0 and 40.

Adjusting the calibration screw of your grinder will shift the grind range, but it does not affect consistency. Let us take an example. If you enjoy your Chemex extraction made with setting 22 on your Virtuoso, adjusting the calibration screw finer will shift your preferred grind setting to 24, or perhaps 26. On the other hand, if you were to adjust the calibration screw to a coarser slot, then your preferred grind setting will shift down- perhaps setting 20 or 18 will result in your favorite extraction.

The only reason to recalibrate a conical grinder would be if the grind produced at setting 1 is not fine enough, or the grind produced at setting 39 is not coarse enough. If the grinder was getting fine or coarse enough, and now is suddenly not, chances are good that following our “How to Troubleshoot a Grind Quality Issue’ video will reveal the culprit. Recalibration may be needed with older/well used units to compensate for burr wear.