Title might be a little obscure and I'm not entirely sure this is 100% the right section.

I'll try to explain myself:

I've seen many posts and watched several tests regarding how burr shape (flat vs conical) and geometry will affect the taste in the cup.

I've read extremely different and contradicting opinions, incomplete comparisons and such, but that's not the issue I want to discuss primarely.

Let's take a 64 mm flat SSP Unimodal v2, often said to produce the "most uniform grind with less fines, leading to clearer cup with more acidity, less body, better flavour separation". Let's assume this to be true.
Then I often read "they are best if you like light roast and pull turbo shots", and this is what I don't understand.

If I wanted to reach the peak of clarity (sacrifiyng a lot of body and texture in the process) this type of burr is a key component (also something you can't change easily down the line) and I get that.

But what If I want to make a more classic espresso recipe with medium roast and have a bit more clarity / bit less body in the cup? Can't I use the SSP Unimodal to achieve this purpose?

Similar discussion with a standard 64 mm italmill flat, doesn't it give ma the ability to pull both strong traditional espressos and more modern espresso (by altering roasting level, grind size, pressure etc)?

Why does it seem you have to stack all the variables in the same direction?

You're not alone in being confused, especially as a lot of the people spouting off on the subject don't have first-hand experience with a broad range of burr sets.

Flat vs. conical is an oversimplification. There are flat burrs that "taste like the best conicals" for classic espresso (the Mythos burrs as one example) and there are conical burrs with good clarity (some of the best hand grinders or the Option-O Mini Moonshine).

"Unimodal" combined with espresso-level grinds is marketing speak, unless you've got a laser diffraction analyzer or access to the data from one.

The burrs are probably right behind water and coffee for determining what is possible in the cup. The way that they break, cut, and squeeze the the beans determines how water can interact with the grinds. Once that is set, there is only so much that you can do during the extraction to change that.

It may be possible to have a burr set that has high mouthfeel and high clarity. I haven't found one yet. Of the better burrs available for home or cafe use, there are some that balance the two in different ways, but I haven't found a burr that clearly separates subtle flavors and gives you syrupy espresso. In my experience, you probably don't want a highly revealing burr set with a classic espresso roast. You may find a detailed reveal of defects in the green, roast bitterness and roast defects a much less pleasant experience that a more forgiving burr set.

A quick, working definition of "lighter roast" when it comes to people discussing high-end burrs -- coffee with little or no "roasty" flavors. More than likely, if your coffee was sold as "for espresso", it isn't light roast*. If your coffee was sold as "for filter" then it may be light roast, or may just be medium.

Certain burrs tend to be "fast extracting". These burrs seem to produce more enjoyable cups of espresso at shorter ratios than conventional burrs. It isn't that you "have to pull turbos" with them. It is more that the espresso "is done" in 15-20 seconds when well dialed in. Going longer results in mainly a weaker drink, though sometimes a less pleasant flavor profile as well. The 98 HU and 64 MP burrs fall into this category (64-mm and 98-mm labeling are totally inconsistent). I'd say the Bentwood and Lagom Mini Moonshine are on the border here, with shorter ratios than conventional burr sets, but not as much clarity. Getting into the 64 Cast v2 ("sweet") burrs, for me, is into a more conventional burr. Stock Mazzer or Italmill 64 mm burr are solidly in the range of conventional burrs.

Some burrs seemingly don't produce enough fines to make pulling espresso at slow flow rates and high pressures possible. Imagine one bed is all 1 cm gravel, the other is a mix of gravel, sand, and mud. Water is going to have a harder time flowing through the mix.

* There are exceptions, such as Tim Wendelboe's "espresso" roast level, which seems to be a medium-light, comparable to or lighter than many roasters' filter offerings.

Hi Jeff and thanks for taking time to reply.

You shed a bit more light into this topic, altho a lot remain shrouded.

I never thought about having maximum clarity and high level body and texture, you have to give some in order to get some, but Ideally I'd expect being able to explore a range of options and find my sweet spot (that might changhe over time) without resorting to buying multiple grinders and multiple burrs, but it actually does seem for this to be the case if you read between lines.

The good news is that the differences are a lot more subtle that all the chatter might suggest. I think that for a lot of people, their own variability and that of their beans might be greater than that among better burr sets. Another piece of good news is that there are several grinders I would enjoy as the only grinder on my counter, some of which are well under 1000€. Among those, I'd still be able to enjoy a wide range of coffees. There are many that I wouldn't enjoy because of significant limitations in either or both in-cup quality or workflow. As long as you avoid the ones that have big flaws for you, you'll have good coffee.

Even if you somehow luck on the "right" burrs for you, next year there will be something different that somebody claims is fantastically better. I haven't found a fantastically better grinder since I moved off my c. 2000 Mazzer Mini. All the changes since then have been reasonably subtle on the overall scale of in-cup quality.

Although I haven't done adequate experimentation to warrant definite conclusions, I am finding that changing baskets can extend the styles of coffees I can extract from the Shuriken Light Medium burrs on my Kafatek Flat grinder. These are the kind of burrs Jeff speaks of which favour fast flows that yield clarity and high EY at the expense of mouthfeel (although this is somewhat coffee-dependent).

When my grinder is used with VST and other high-flow baskets, darker (not necessarily very dark) beans can easily over-extract, producing unwanted flavours. As noted above, I find this affect can be countered by using baskets with different characteristics. For example, I have found that I can pull surprisingly sweet, satisfying flavours from the darkish Kimbo Espresso Napoli blend by using he new WAFO blend/4-steps basket with my Kafatek high-extraction grinder.