hthec Yes, it does, but it’s not quite that simple. It depends on the degree of sound, rhythmic whisper to a rhythmic roar, before ending in a loud continuous rub. Or a whisper to a relatively quite glide….And over how many microns these changes happen.
Shimming burrs and marker pens isn’t that effective, because already significant pressure in engineering terms is required to make a mark in marker.
Aluminium foil is commonly used to shim and the thinnest foil is about 20 micron, more heavier duty foils can be 2 or 3 times thicker. A human blood cell is 5-7 micron diameter and the burrs themselves can have variances up to 5 micron, or more depending on manufacturer. Certain types of variance can’t be shimmed out.
To put it in perspective a human hair is a massive 70 micron.
On a very well aligned grinder moving the burrs 12 micron further apart can add/deduct 4-6 sec or more on espresso shot time, depending on a few factors.
A grinder needs to have very fine adjustability to be suitable for espresso.
Most commercial grinders are not well aligned at all. Single dosers need to be very well aligned. It’s a very big subject, one that when well understood, explains many things we see in grinders. Even some revered grinder manufacturers have said things to customers about using washers under the burrs, which clearly displays a misconception about burrs and alignment.
A very rough rule of thumb, the closer you are to burr touching for espresso, the progressively worse your burrs are aligned. So if you are 6 to 10 micron away from burr touching, then the burr alignment is not great which has other effects as well. If you are 30-40 micron from burr touching for espresso, or more depending on coffee, you’re doing great!
P.S. the above applies to single dosing a flat burr grinder.
