Set the gap and brew with the crushed grain. If you don’t get stuck tighten the gap and brew with the crushed grain. Repeat until you get a stuck mash then go back to the last gap that produced a mash where you didn’t get stuck.
Three thoughts:
- Measure the gap in the same place each time you adjust.
- Perform everything else as you normally would (e.g. if you stir at 20 min or something do it the same every time, same water volume, same pump setting, same everything except the gap).
- Use the same amount of grain for this series of brews.
It’s a tedious process but it’s likely the only way you’ll know how much you can crush the grain to the point of a stuck mash on your system. Your system may allow a very fine flour. Mine won’t tolerate flour so I use more grits than flour.
An alternative to measuring the gap is to measure a set amount of grain on a standard sieve. Using a standard shake protocol, measure what stays on the screen vs falls thru. I shoot for 70% remaining on a No 14 sieve. There’s a match mark Mr JSP etched onto my mill and adjustment knob. I know that the right edge of the mark on the knob aligned with the left edge of the mark on the mill is my go-to setting.