So many questions Moon [emoji1] I'm not sure about the causality of flavour profiles from different burrs so I'll duck that line of questioning. The best commercial grinders are better than the best domestic grinders in that their grinds will extract better. They use bigger (longer cutting path) burrs, more torquey engines, some grind very slowly (Ceado E92), some manage temperature (Mythos One), they work to tighter tolerances (keeping the burrs parallel), and use more resilient construction values. This does not mean that they are necessarily home user/kitchen friendly: they can be huge, retain lots of grinds, and even be noisy. Many can be adapted for single dosing (no retention) though. And I'm certainly not saying all commercials are good. I am saying that in my experience the best big commercials are way better than home grinders. I'm not sure you can say flat burr = more uniform grind either. It does seem that Mahlkoenig are aiming at more uniform grind though following the resurgence of the EK43. It's flat burrs are notable for the more uniform grind but it's not designed to be single dosed (on/off/on/off) hundreds of times a day in a busy cafe. So they're bringing out the Peak which looks a lot like a K30 but has new burrs which are designed to deliver a more uniform particle size. I have played with: Eureka Mignon (loved it because it's quality and utterly unpretentious), Mazzers Mini E (weak, no advance on Mignon), Super Jolly (better), Royal (very good), Robur (excellent), EK43 (remarkable but not my style of espresso), Versalab M3 (drive shaft prevents burrs from operating parallel), Mythos (very good), Ceado E92 on its way. All ratings refer to in the cup performance (ie completely subjective, feel free to disagree). If you just judge on taste, good commercials go further than home grinders reach. It's not just that they are stronger, although they are designed for heavy workloads. OK that's enough from me. I'm an enthusiastic amateur not a professional. [emoji1]
