A lot of us use espresso grinders at home that are meant for commercial environments. They come with these huge bean hoppers that are probably filled several times a day. The turnaround is so fast that coffee doesn't have time to "go bad" in the hopper. At home though if I were to fill my hopper with half or three quarters of a pound of beans it would take a week to run through them and those beans would probably not taste as good at the end of the week as they did at the beginning. This is where single dosing comes in. Grind just enough for the shot you're about to make and then keep the grinder as clean of grinds as possible so there isn't any stale coffee in the next shot. The dilemma is, some of these commercial grinders aren't as consistent without lots of beans in the hopper. Personally, I can't tell the difference in taste between grinding with a full hopper and grinding 20g of beans. I do notice that to achieve the same shot timing I do have to adjust the grinder setting. No more than a click though. So what I do is to fill my super mini hopper, actually a shot glass that fits the neck of my grinder exactly, with three shots worth of beans and then grind my one shot. This is convenient because it amounts to one full glass of beans and is enough to prevent popcorning while grinding. Then at the next session I fill up again and purge about 5g and then make the next shot. I find this to be a decent compromise to keeping a full hopper of beans and only grinding one shot at a time.
So what is it about these commercial grinders that requires the bean column for grind consistency? I've read that the Pharos hand grinder from Orphan Espresso is a fantastic espresso grinder that uses burrs found in commercial grinders. It is most definitely a single shot grinder. Is it the speed difference between hand grinding and using an electric grinder? Or would the Pharos work that much better with a ridiculously large hopper?