Grinding coffee for non-espresso brewing at home is a pain in the tits. Short of finding space and the budget for a shop grinder your choices are limited and there a lots of concessions. When the Mahlkonig Vario arrived it was lauded as a grinder which could deliver a quality filter grind, and an espresso grind and sing and dance and do everything in between. Its performance grinding for brewed coffee left an awful lot to be desired.
For the past few months, however, on a daily basis I have been brewing filter coffee with a Mahlkonig Vario. The results have been excellent. The difference, notably is that the stock ceramic burrs have been replaced by a set of steel burrs designed specifically to produce a coarse grind.
What are the effects of swapping these burrs:
- The grinder is rendered useless for espresso (one step from touching will produce a gusher).
- The grind rate is greatly decreased (to about 1g/s at a filter setting – the old burrs do faster than that at an espresso setting).
- The grinder is louder.
- The noise coupled with the extended grinding time is a minor annoyance in a domestic setting, and perhaps a major annoyance in a light commercial setting.
- The uniformity of the grind produced is comparable to some shop grinders.
This result suggests a few theories and questions.
Burr size is not necessarily the major determinant of grind uniformity. Perhaps small burrs are typically not good at filter grinding, because small burrs are typically not designed for filter grinding.
Why can some grinders not grind fine enough for espresso?
Is the speed reduction a factor in the output quality or a symptom? Does it suggest that the burr has to strike the coffee more times to achieve sufficient size reduction. Does this mean that the comminution is less explosive? … more controlled? Is there a relationship between burr size, grind rate and uniformity?
Even though the burrs are dramatically different looking, it is hard to elucidate the aspects of the burr desing responsible for these changes. The breaking teeth are shallower and there are many more of them. The cutting teeth are deeper and present a less angled face (they are closer to being on the radial axis). All edges are noticeably sharper to touch.
In any case, these burrs are not yet widely promoted, but they should be. Those in the business of selling Chemexes, Harios and the like to end users should want to offer these. The Vario is a solid grinder, and can with these make a very competent filter grinder. Even better perhaps would be a grinder using these burrs with fewer of the Vario’s bells and whistles, similar or better build quality and a somewhat lower price.
It would be nice if domestic grinder manufacturers defocused on espresso. Hopefully a critical mass of end users will emerge who understand the requirement for a better quality grind, to whom dusts and shards is unnaceptable. It requires enough users who don’t give a damn about espresso grind to create the market to drive these products.