Do bigger conical burr sets make better espresso?

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peacecup
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#1: Post by peacecup »

So as not to quash the discussion on burr-set size...

Why would a larger-diameter burr set make better-quality grinds? Assuming both burr sets are properly aligned, why would a larger burr set be more consistent?

PC
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LaDan
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#2: Post by LaDan »

Because results show that they are.

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sweaner
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#3: Post by sweaner »

But the question is why? And what is the real difference. Will an 83mm set really work better than a 71mm? Or 68mm?
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drgary
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#4: Post by drgary »

Jack,

Good topic. Since you're interested in delving into the reasons large burr sets are considered better, are you also bringing in other factors, such as type of burr, whether parts of the burr cut or crush, etc.? Perhaps you or someone posting on this thread can reference earlier threads that have been written here and elsewhere about burr size and design and summarize that information for a useful discussion and testing if indicated.
Gary
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coffeedom
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#5: Post by coffeedom »

This is a good question. I asked the same earlier when I wondered why the 38 mm Lido was positioned for drip/press while the Ascaso and Nemox grinders using the same 38 mm burr set were espresso-only grinders.

A lot of people are claiming that the larger conicals make better espresso and it could very well be true but I've yet to hear a convincing argument as to why. A solid logical argument is a good place to start. Proving it with blind tasting (to Jack's 95/100 criterion) is a tall order, but hey even just a sound argument and maybe a few comparisons of grinds and a few tastings would help support the claim.

I regularly use a 64 mm flat (SJ), 54 mm flat (Vario) and have probably the best 38 mm grinder currently made in the Rosco. They all make very good espresso though I tend to get just a bit more body from the flats. But the Rosco vs other conicals is a different argument altogether.

If anything, the smaller conicals should produce LESS fines, not more, and consistency for smaller burrs is bound to be better than larger burrs because the cutting area is smaller and there is a more focused cutting action. This would especially suit single dosing I would think. As well, I don't really understand the argument that a larger conical is somehow more consistent (from shot to shot) though there may be a good reason why this could be.

Perhaps rather than assuming that larger conicals make better espresso and then searching for reasons why this is so, we should take a step back and ask if it is really true to begin with. I'm not disputing people's claims but simply wondering if there is a momentum we are getting swept up in which is assuming a conclusion before it's properly hashed out.

At this point it seems like a very tenuous observation that larger conicals are better and even Jim Schulman has ranked 38 mm burr sets up there with the Robur in the TGP.

Perhaps a fuller picture can be arrived at in this thread.

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tekomino
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#6: Post by tekomino »

I just find it funny that people who have not tried large and small conical grinders side by side are looking for some kind of proof. If you are trying to convince your self that large conical burrs are no different than small conical burrs then nobody can change your mind, you will always find something to cling to. Instead of throwing arguments around, try and report yourself... There is no point in arguing if you have not tried it.

coffeedom
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#7: Post by coffeedom »

Not sure if that is directed at me but hey relax a bit there. I'm not convinced the smaller conicals are better and if you read my previous posts you'll see that like many here I am genuinely interested in the question. We can't all run out and buy every piece of equipment to test and compare everything ourselves, though it seems that is exactly what you have done :D.

Jack's question is a good one and your attempt to kill the conversation by saying that people are just trying to justify their own purchases is rather weak. How about some solid explanations? That would be more appreciated than your dismissive tone. And yes I've read these forums for years and don't need to be told to read the varied opinions of some of our more esteemed members.

FWIW, I'm interested in buying an HG One but am curious to know if I will truly get much better than I currently get with the Rosco or my other grinders.

And for the sake of knowledge, what is wrong with asking this question? And what is wrong with trying to answer it properly?

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another_jim
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#8: Post by another_jim »

This thread is most likely an exercise in vanity; but here goes anyway.

I don't know why large burrs are better, and knowing why is irrelevant to the fact that they are better, at least according to every person who has ever tried them.

There are various theories why large burrs are better. 1) they do not require the same building tolerances as small burrs, since the required tolerance is proportional to burr size. 2) They have longer grind paths and therefore reduce the beans to a powder more slowly and uniformly. 3) they have better feed-in (beans crushing sections), and therefore create a smoother flow of the particulates through the burrs.

Each of these theories has been dissected ad nauseum. The only way to test them is to design custom burrs that does only one of them differently from a small burr. Since none of us can manufacture burrs sets; we cannot test these hypotheses.

Personally, I'm a proponent of the grind path length hypothesis. The Vario burrs are very narrow, 50mm. But the burrs are angled very obtusely, so the effective grind path is similar to the Super Jolly's. But we need more of a data set than that to get anything that counts as evidence for a burr hypothesis. On the other hand, by trying the Vario repeatedly compared to larger and smaller burr grinders, I can report with complete confidence (actually about 99%) that the grind quality is better than the small burr grinders, and roughly equivalent to a super Jolly and other 64mm grinders.

For those who are statistically challenged: it's about the number of cases.

When comparing two grinders, every comparison shot is a case, so its very easy to come up with lots of cases and strong, statistically supported conclusions about which grinder has better grind quality. HBers have made thousands of these comparisons and the case is completely overwhelming for the superior quality of larger burrs. The only way to challenge this is to impugn the honesty of the dozens of people who have made these comparisons (which is why people are getting very pissed about these posts, Jack).

But in the question why grinders with attribute X are better than grinders with attribute Y, the cases are very few: only the different brands of grinders or burrs. This is such a small universe that statistical approaches are unworkable.

Since we Hbers can drink lots of shots, but can't forge burrs; we can easily test which grinder is better, but not hypotheses about why that is so.
Jim Schulman

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HB
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#9: Post by HB »

We can speculate why grinder X or espresso machine Y performs well, but too often that line of thinking led me to wrongly assume that grinder Z or espresso machine A sharing the same design characteristic would perform similarly. Pressure profiles, preinfusion and the forgiveness factor explains why I gave up asking "why". Tekomino is right: You must try two specific units side-by-side to have a meaningful discussion about how they compare. Comparing two hypothetical units on specifications is nothing more than a thought experiment.
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#10: Post by coffeedom »

It may be pointless to compare hypotheticals, but that is exactly what people are doing. The claim is that larger conicals are better than smaller. Some specific comparisons have been made such as Lido vs Rosco vs Pharos, but for the most part the observation is categorical. It's only natural to look for general reasons why this could be the case.

Thanks Jim for laying out some ideas about this. I for one enjoy posts like this because these are the tough questions to answer. Collective claims are important and should not be dismissed but also need some support by way of reasoning. Perhaps there is a history to this question that I'm not aware of but I see no reason why anyone should get pissed. Aside from Dennis, the response to this question on this and the HG One thread has been been positive. I'm sure I'm not the only one who would like to get more opinons about larger conicals vs smaller.

This question applies to 83 vs 71 mm as much as 68/71 vs 38. The HG One offers big and bigger burr sets and this piques my curiosity as to how they differ. The logic of larger burrs producing better grinds would suggest that the 83 is the natural choice.

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