I'm not trying to spark a debate about which is better or whatnot, so hopefully the thread title is okay, I'm more looking to see what the discussion is regarding the current state of "titan" level or the upper echelon of grinders for espresso, specifically as it pertains to large flat burrs and large conical burr grinders.

The reason I ask is because it seems like there has been a role reversal of the large flats vs large conicals in what coffees or styles suit them best and the style of shot that is pulled. When I started lurking the board 4 or 5 years ago, the general consensus at the top end was the large or titan level flats worked best for "bass notes" (chocolates, caramels, nutty flavors, etc.) and that the titan conicals would provide more flavor separation, allow lighter and more subtle flavors to come through, and suit lighter roasted coffee better, as summed up by Jim's post back in 2006 MKXR/MK7R Conical Burr- Worth the upgrade?:

another_jim wrote:The evidence from espresso lovers suggests that conical grinders tend to perform better than flats; with the advantage becoming more obvious as the roast level gets lighter. This is also true for regular brewing.

But more recently, we are seeing the large flats like the Peak, EK, K30, etc., given the nod for higher yield shots with light(er) roasted coffees, sighting more flavor separation and clarity.

Isn't that just the opposite of what the consensus was 5 or 10 years ago? Or is it the case that these new big flats are different that the big flats of that time and we have entered a new "era" of big flats? And if so, why is that? Is this just a by-product or specific to high yield shots? Is it due to burr design, or roasting styles are changing to specifically suit, it's currently en vogue, etc.?

I know I left out some of the major players in my examples, so please don't take offense or get caught up in that, as my discussion is less about the specific models of grinders themselves, and more about understanding what is driving the shift and why, or maybe if there even is a shift.

I would expect that it's a lot easier and cheaper to iterate through versions of flat burrs to look for quality output and once you have the perfect solutions to get the coffee from the burr to the portafilter it probably doesn't matter if the burr is flat or conical.

Ira

I think we're in a new "era", but not necessarily of titan grinders.

I believe part of the problem is that we're lacking rigorous testing of today's high-end grinders with today's high-end coffees. The other part of the problem is that the landscape is changing, which makes it difficult to draw firm conclusions from tests.

First off, the Titan Grinder project documented on this site was carried out a number of years ago, when things were somewhat different. Roasters were still moving to lighter roasts and the use of refractometers to determine extraction yield and concentration wasn't common. The current trend toward large flats seems to have been prompted by a realization that it's harder to extract light roasts, as confirmed by refractometers, and that previous 3rd wave techniques, like updosing and pulling short to counter bitterness, no longer work well with the products of an increasing number of specialty roasters.

A few machine manufacturers responded by providing pressure profiling features (e.g., LM, Vesuvius). It seems that pressure profiling doesn't have the hoped-for impact on extraction yield (see Ben Kaminsky's data and video), so flow profiling and/or or long pre-infusion were introduced (e.g., Slayer).

At about the same time, Kaminsky, Perger, et al, found at least two ways to increase extraction yield from light roasts: 1) use a flat "unimodal" grinder with large burrs (e.g., the EK-43) and 2) pull longer -- a lot longer.

Method #1 seems to have sparked a move toward grinders with large flat burrs. For example, Mahlkonig has come out with a more user-friendly and counter-friendly on-demand grinder with large flat burrs (the Peak) and Lyn Weber is coming out with the EG-1.

I don't think we can say that this trend has moved us into a new era of titan grinders. As I said, we don't have rigorous test data proving that large flat burr grinders produce a grind that extracts more or better than large conical burr grinders. It could very well be that simply pulling shots longer is the primary reason some baristas have been able to get better extraction yields from light roasts.

Unfortunately, it's not easy to evaluate the particle distribution of grinders, which makes it harder to draw conclusions about the benefits of any particular burr size or configuration.

Finally, the problem of the changing landscape will likely complicate matters: Roasters aren't keeping their heads in the sand. I'm sure the messages about underdevelopment and difficulty extracting aren't falling on deaf ears. I expect more and more roasters will slide back towards darker roasts, trying to walk that fine line between "underdeveloped" and "roasty". Roasting is a complex process, so it's also possible that new techniques will improve the chances of hitting the sweet spot. Once the roasts change, then the optimum titan grinder configuration may change as well.

wow, maybe it won't be a discussion after all, great response, Dick! A lot of what you said makes a lot of sense. And there definitely seems to be a number of different things going on simultaneously and it seems like they're all driving each other at the same time as well.

My understanding is that Slayer was launched in 2007 but the Strada in 2010... so the history isn't quite that simple - expected when attempting brevity!

Progression of insight is not always synonimous to making progress, many things are moving like a pendulum so we may just find ourselves on the start of the return movement...

Peppersass wrote:A few machine manufacturers responded by providing pressure profiling features (e.g., LM, Vesuvius). It seems that pressure profiling doesn't have the hoped-for impact on extraction yield (see Ben Kaminsky's data and video), so flow profiling and/or or long pre-infusion were introduced (e.g., Slayer).

Great answer; but I have an additional thought on this part. Kaminsky is working within the framework of commercial espresso, in essence, "How can you do a good third wave shot when there's a line out of the door?" I don't think there's a real distinction between pressure profiling and flow profiling + preinfusion since flow is a function of pressure plus the constants of the flow path. The differences come in the context of finding what works best in a busy cafe.

As to flat burrs. Commercial conicals and large flat burrs where designed for increased throughput, not increased quality. The better quality of the conicals was accidental; as is the better quality for light roasts of the EK43. The new generation of espresso flat burrs seem to have been built with single dosing and shot quality in mind. Sadly, none of these were part of the original titan grinder project, but the anecdotal evidence from the Mythos, Mahlkoenig and other new flat burr designs indicates that these are equals to the commercial conicals.

We're making better grinders as we learn to roast coffee better, it's that simple.

Kaminsky would likely have a harder time getting consulting gigs if it wasn't for the fact that many of the cafes/roasters he was involved with had very little skill in roasting well, rather, they were roasting to a very tight Agtron range across all coffees. All very bright, barely outside of a cupping/sampling roast. That garbage was either soupy broth, or sour juice. Hardly extractable.

Famous coffee pro's are good for the industry, moving things forward for the rest of us. But never in the past has coffee as quality (not moving the line, or serving a very cheap caffeine transport) been more important. Thus, equipment is getting more complex to tackle these new demands.

Ditto, Great answer Peppersass.

another_jim wrote:Great answer; but I have an additional thought on this part. Kaminsky is working within the framework of commercial espresso, in essence, "How can you do a good third wave shot when there's a line out of the door?" I don't think there's a real distinction between pressure profiling and flow profiling + preinfusion since flow is a function of pressure plus the constants of the flow path. The differences come in the context of finding what works best in a busy cafe.

I hear what you're saying (with pressure and flow being connected) but there's a notable difference in the cup between the two styles:
- Lower pressure higher flow: IE: Pre-infusion under line pressure. Such as with e61 variants, GS3 etc..
- Higher pressure, lower flow: Slayer style.

Both will require a finer grind than a machine without pre-infusion and a fast ramp (such as a Linea). But the second (Slayer style) requires an even finer grind. Much much finer (as the coffee is exposed to the water at a much slower rate). Which in turn changes the taste/balance/body of the coffee.

The effect is quite pronounced. Even with a medium roast coffee and any decent grinder.

If you can, I'd encourage your give one a try.