I'm prefixing what follows by saying that I'm perfectly happy with my grinder (for the time being). But my question is: What are the characteristics/features of a good grinder?

I mean on an espresso machine you will pay for stainless steel, programmable logic controllers, pid's, double boilers, etc. It's kind of obvious where the money goes.

But on a grinder? Other than reviews how can you know?

burr material, burr type (conical, flat, width), burr rotation speed, noise, stepless/stepped, Digital or manual, metal or plastic construction, dimension.

there's probably more..

You've listed a few attributes there Marc, but you haven't said what's good and what's not. For example I has a conical grinder that was useless for espresso making. My current machine has flat burrs and is very good. What is an ideal rotation speed etc?

I hear what you're saying Dan, but there ought to be verifiable and measurable parameters that separate the wheat from the chaff. In other words good machines surely have common denominators that not so good ones don't have. Or if it is not possible to easily measure what the constituents of a good grinder should be, then maybe what we need is a buyer's list of what is currently known to be good.

Expensive grinders tend to be better. As do the ones with large burrs.

Ian_G wrote:I hear what you're saying Dan, but there ought to be verifiable and measurable parameters that separate the wheat from the chaff.

No such parameter would be set on the chaff side by the manufacturer of any grinder costing more than a few hundred dollars.

The hidden premise of "spec sheet shopping," if the goal is to find something better as opposed to more suitable, is that design engineers routinely make mistakes, and the consumer has to find the one good combination of features in a pile of nonsense products. Shopping this way improves vanity, but not kit.

Spec sheets are good for finding what's suitable: e.g. don't buy a grinder that's 20 inches high, if your cabinets are 18 inches high; but I don't think they can do much more than that.

But ... For us espresso hobbyists, there is one slight fly in the ointment. Most of us do not use espresso equipment the way it was designed to be used. We don't fill dosers, so the undesigned and accidental way dosers distribute single shots is of interest to us. We tend to overdose shots compared to Italian design values, so the behavior of groups and baskets with 4 to 6 grams more coffee in them than the designers anticipated is important to us. The problem is that these traits will not show up on spec sheets either, since nobody knows what measures will predict them.

For instance, a Silvia-Rocky combo is fairly easy to use well with coffee ground fine enough for 12 to 14 gram doubles, but when you put in an LM basket and coarsely ground coffee at 18 to 20 grams, you get a bitchy setup with a huge learning curve. There is no way to write a spec sheet that will tell you this -- you need the report by a competent hobbyist or by a pro who deals with hobbyists.

"Conical" does not mean good or bad for espresso no more than the case material. There are probably some very cheap conical grinders that might be good for flax seed but nothing more.

When you enter into the top-end grinders which sell for (a guess, $750 and above) are not moved through high volume so right off the percentage of cost of the R+D and initial manufacturing costs are going to be greater per unit. But you get higher precision throughout. Bearing precision and size, shaft diameters, alignment, and so much more. Hold the upper burr carrier of a Mazzer Kony in your hand and you will see what your Euros buy. A really cheap, low-end grinder could give up the proverbial ghost after grinding twenty pounds of coffee. The top end grinders don't fully break in until they grind ten or fifteen pounds.

And reviews...? You will find a lot of positive reviews of Rocky grinders. A lot of reviews. Those buying that grinder most likely are buying their first "real" grinder. Now read the reviews of those stepping up from that grinder. The Mazzers, the Macaps, the Compaks. Most of these make the Rocky look like a toy, not only in build but in function as well as quality of the grind. Everything is relative, but when you are at the pointy end of things, or at least to say, if you can see the pointy end from where you stand, there are quality factors that don't show in specifications. It it were only that easy.

The perfect home grinder? Hasn't been made. The Versalab M3 comes close, but it has its own problems.