Why do "Titan" conicals have a bigger sweet spot than smaller grinders?

#1: Post by **dominico** » December 26th, 2014, 3:01 pm

I have heard it said frequently on these forums that bigger "titan" conical burrs have a bigger sweet spot and require less adjustment than smaller burrs, or even flat burrs. I have experienced this myself when comparing the grind fineness between my Pharos (if you would consider it a Titan grinder or not, it does have large conical burrs) and my Rocky, which has smaller flat burrs. To achieve the same 25-30 second pour at the same dose (by weight) the Rocky grounds have to be visibly more fine than the Pharos grounds. Both tasted good, with the Pharos being less bitter in my possibly unconsciously biased opinion.

I've thought about it a bit and have a few different ideas as to why, but I am interested in hearing from someone who may actually know rather than just going with my conjectures.

Thanks,

#2: Post by **Joco** » December 28th, 2014, 7:56 am

Have you done any research on particle distribution size with the large conicals? I would think it has to do with the amount of fines that the large conicals throw. The flats generally have a more consistent grind size.

Here's an interesting place to start (although im hesitating to call it a bigger sweet spot).

#3: Post by **Nate42** » December 28th, 2014, 1:36 pm

It pretty much has to come down to particle distribution. If for example in an espresso flow is dominated by fines but flavor/extraction is dominated by the larger particles, if you have a grinder that produces consistent fines over a wider range of settings, you will have a wider range of settings that have an acceptable flow rate.

I think the whole thing is analogous to tube guitar amps. From a purely technical perspective, if an amplifiers job is to make a signal bigger without changing it, these amplifiers are terrible. Even though this initially wasn't an intentional design feature, the particularly way in which they distort the signal when overdriven has come to define what people want and expect from guitar sound.

Likewise, the particular particle distribution from conical grinders has come to define what we expect from espresso. "Better" grinders that produce a more uniform output (ie bulk grinders usually used for brewing) either can't produce espresso at all, or like with the EK43, you get something that isn't quite the same as a traditional espresso. Obviously the shots you can get with an EK43 are gaining in popularity recently, but most seem to agree its a whole different animal.

December 28th, 2014, 3:59 pm

Thanks guys,

I read up on particle distribution and it all makes sense now.

Or does it?

#5: Post by **aecletec** » December 28th, 2014, 7:31 pm

I don't think it should.

#6: Post by **FotonDrv** » December 28th, 2014, 8:04 pm

Very interesting graph!

What Mazzer Robur was used, a 71mm or 83mm burr set? Does anyone know without wading through that monster Thread?

December 29th, 2014, 12:47 am

Almost everything said about grind size distributions by Ben Kaminsky, all other professionals, and grinder manufacturers, is simply self serving commercialism. Laser sizers are not accurate enough to support any of these assertions. I do not know why conicals need fewer adjustments than flat grinders; and I have a great deal more distribution data than all these pontficators put together

The TGP2 thread shows a controlled experiment of about 20 distributions collected from flat and conicals making espresso full hopper/single dose, 14 or 17 grams, and flat or conical. There was no significant difference at all between the collected graphs -- they are samples from the same distribution space, as seen below There is no solid conclusion to be drawn from them.

My personal, entirely unproven speculation is this. Grinding coffee is like breaking crackers -- the crisper the cracker, the more crumbs; and the more brittle the bean, the more fines. Different coffees need different grind settings for constant doses because they are more or less brittle. The least brittle beans, Sumatras, and the most brittle, Central Bourbons, need grind adjustments even for conicals. The others do not, but do need adjustments for flats. Moreover, changes in brittleness that come from moisture absorption and aging need adjustments for flats but not conicals. My theory is that since conicals have much longer grind paths than flats, this suppresses differences in brittleness, in effect, they crush the beans more gently.

If the explanation does lie in the response of bean brittleness to burr geometry, reading distributions to explain the conical/flat difference is about as useful as reading entrails. Just because you have an expensive and cool measuring instrument doesn't mean the measurements have anything to do with the question you are asking.

December 29th, 2014, 1:01 am

another_jim wrote:If the explanation does lie in the response of bean brittleness to burr geometry, reading distributions to explain the conical/flat difference is about as useful as reading entrails. Just because you have an expensive and cool measuring instrument doesn't mean the measurements have anything to do with the question you are asking.

#9: Post by **aecletec** » December 29th, 2014, 2:11 am

Thanks for weighing in Jim, great input as usual.

#10: Post by **Joco** » December 29th, 2014, 8:26 am

Jim... Just curious was the same brand, model, fw, etc particle sizer used for your sizing and Kaminsky's?

I do find it interesting that many cafes and baristas for that matter seem to be slowly making a switch from the large conicals to the large flats. Perhaps there's something to large flats.