Grind Size and Extraction: the crushed garlic model - Page 3

Grinders are one of the keys to exceptional espresso. Discuss them here.
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Denis
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#21: Post by Denis »

I can get the same total time and the results will be the same. The coffee from guatemala came waterry even with a bigger total time. Clearly lower tds.

A bigger total surface means more extraction and richer taste. This can be explain by 2 things,:


How can you get more extraction with bigger particles?

a)The flakes from.flat grinders don't allow a even extraction from.top.to bottom.
b) the particles from.the ghost burrs are fracturated and have more artificial porosity that results in higher permeability so a higher total surface to extract more.

This is easy to prove with a refractometer. But in general.better tasting coffee or a more balanced cup means higher extraction than a sour, salty, bitter cup. This corelates to espresso to, just that it is easier to manipulate and sieve brew grind.

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another_jim
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#22: Post by another_jim »

I appreciate all your extraction and fines OCDs, I really appreciate knowing ahead of time that you will be saying exactly the same thing in every grinder discussion - remove the fines! -- you don't need to if you are using good coffee! But you're not actually answering My question:

Again: how come you have to grind way coarser on the Fuji than on the Bunn to get the same taste?

The only possible answer is a systematic difference on the particles. So far two good possibilities -- the larger particles are fractured and let water through them, or the larger particles are scragglier, and have more surface area for the water to reach.

Oops, Denis just said the same thing while I was writing this.
Jim Schulman

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OldNuc
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#23: Post by OldNuc »

The antique motor driven grinders once seen in all grocery store have several rows of what would best be described as a rough cast ghost burr and the motor driven rotating burr is a flat design with radial continuous grooves. They produce no detectable fines in the output when compared to a regular grinder. What fines that are produced end up stuck on any opposite charged surface that is close so there are indeed fines but it takes quite a bit of grinding time before cleanup is required.

Today is the first time this grinder has been opened up in 35 years of use. Note that there is nothing that would pass for sharp in this set of burrs. Look to me that they were designed for crushing and not cutting. This dates from the late 1920s to very early 1930s.

Motor driven cast burr.


Fixed cast burr. The 2 coffee obscured screws hold the cast housing to the motor.

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Denis
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#24: Post by Denis »

Try to simulate a porosity test simplified.

Grind the same quantity of beans at the right settings for brew method. Soak for same period the particles, drain the excess water then weight. If you have a big difference in the ghost burr grind (heavier) then you have a bigger porosity. Sure this has to be done several times to eliminate errors but it is a starting point. Normally the water penetrates the walls for a limited value (100 microns in espresso under pressure) but this is proportional to time. If you see an anomaly in the grind from ghost burrs then you can assume it has more porosity/fractures.

As a matter of fact, you could just do kalita wave or v60, for 3 mins, then just weight the wet coffee and see the difference. I might do that tomorrow.



I sieve all the coffee for brew because I don't like the taste from over extracted fines. The coffee should not be strong, in your face, but subtle with fruit/flower notes and sweet. Taste like wood, tobacco, cacao, smoke from the roaster, astringent should not be present at all. All the notes should come in a perfect balance, without a dominating flavor.

The fines make the coffee unclean. I would never go back to non sieved coffee for brew.

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another_jim
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#25: Post by another_jim »

Denis wrote:I sieve all the coffee for brew because I don't like the taste from over extracted fines. ... Taste like wood, tobacco, cacao, smoke ... should not be present at all.
No single malts or bourbons for you!

Weighing the wet grinds is a good idea. I'll try it as well.
Jim Schulman

nuketopia
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#26: Post by nuketopia »

another_jim wrote:You keep lecturing, but I'm not hearing an explanation or model for the difference. Instead you seem to be telling me and all the other Fuji users that we're imagining things. IMO, the whole spiel about particle sizes, shapes and distributions versus extraction and taste is seriously incomplete.

Moreover, it is mostly non-falsifiable in a statistical sense, since there are a very large number of shape distribution characterizing variables, enough to explain all variations in taste and extraction by simple correlation.

It's far better science to look at one clear case that is anomalous, and find out why. The Fuji 2220 is anomalous; so lets find out why.
And you keep conjecturing with facts not in evidence.

Where are the objective measures?

Let's see a particle distribution histogram, even from sieving. Let's see a refractometer reading.

Is the Fuji 220 anomalous when measured against objective tests?

Are you looking for reasoned discussion or affirmation?

CwD
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#27: Post by CwD »

another_jim wrote: Again: how come you have to grind way coarser on the Fuji than on the Bunn to get the same taste?

The only possible answer is a systematic difference on the particles. So far two good possibilities -- the larger particles are fractured and let water through them, or the larger particles are scragglier, and have more surface area for the water to reach.
More severe channeling in the Guatemala brew. Virtually all people's percolation coffee is severely channeled. Perhaps the Fuji is simply less sustainable to it. Unless we're seeing numbers like 26-28% with this grind size it makes sense without needing any fundamental difference in accessible surface area. Even 22-23% is laughably low compared to what's there to extract, easily within range of the grind size if something about it makes channeling less likely.

Of the other models, fracturing particles could be a possibility, but I don't see it as particularly likely until there's something existing models can't explain. But it should have the right effect if it does happen. I don't particularly see the second explanation working though, there would be gains but nothing like the exponential losses when volume increases to the cube while surface area only increases to the square.

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Denis
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#28: Post by Denis »

I don't think its channeling as in espresso, but as I said uneven extraction, the lower beds are not so well extracted so you are extracting way less, in fact we can use under extracted therm better than channeling. The coffee from the guatemala tasted like it was 1:25 ratio compared to the Xeoleo.

I was thinking about the fractures in the particles. In order to extract you need water to flow thru something. If the fracture is closed (dead end) the water will not flow, it will only saturate the pore/fracture and extraction will be limited from there. So I don't think that having fractures in grind will increase extraction by a lot or by a significant value. If the fractures are big then the particles break, if the fractures are small there is close to no impact. You need to push the water into the coffee grains to extract, you can not extract from a dead end fracture, or a static spot like a fracture.

Its more of a particle shape and the order/arrangement, this will dictate how the water flows. If your water doesn't flow efficient in the entire coffee bed then you are having "channeling? This doesn't sound right, you have an uneven, under extracted zone. So you extract lets say 70% efficient, and from 30% inefficient. And at the end you have a 20g in =300g out but you pushed water efficient only in 14 g of coffee so you should extract only ~ 210 g of brewed coffee.

Maybe the dose has a bigger impact on the brewer than we think. Maybe alternating 14-16-18-20g in a V60-02 gives us an idea of TDS. This is the same as in espresso puck height.

This means I have to lower the dosage from the Guatemala to extract more. This means that a certain burr type will work better than others with lower or higher dosage, so let's say its not fair to compare 2 type of grinder using the same dose. In espresso when you pull with 2 grinders, you dont adjust the dose, you adjust the profile, but in v60 the pours/time stays the same, so you have to tweak the dose. Adjusting the dose happens in the machines that have fixed profile for the shot.

Denis out.

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another_jim
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#29: Post by another_jim »

CwD wrote:More severe channeling in the Guatemala brew. Virtually all people's percolation coffee is severely channeled.
Perhaps. But I either steep or cup my brews
nuketopia wrote:And you keep conjecturing with facts not in evidence.
Where are the objective measures?
Let's see a particle distribution histogram, even from sieving. Let's see a refractometer reading.
Is the Fuji 220 anomalous when measured against objective tests?
Are you looking for reasoned discussion or affirmation?
You can simply say "I don't believe you" instead of posting over and over again.

To repeat: I calibrated the Fuji for cupping according to the SCAA protocol (70% to 75% passing through a size 20 screen), and easily picked out the cups compared to the Bunn because they were more extracted tasting, i.e. softer, with more prominent sweetness and body, and subdued acidity (OK for brewing very bright coffees, miserable for cupping). Then I ground it far coarser (how coarse? -- well none of it passed through the size 20 calibrating screen; I haven't seen a grind this coarse since canned coffee for percolators) and the cups became much closer in taste. I could still pick out the Fuji, barely, for a slightly cleaner taste (presumably the lack of fines due to the much coarser grind setting).
Jim Schulman

CwD
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#30: Post by CwD »

Be interested in seeing how those cuppings measure. I can test any samples mailed to me, as far as I've been able to test readings are stable over at least a week if stored well.

I'm interested to see if it's actually extracting higher or just reaching certain extraction associated tastes sooner. If it's not extracting higher but just reaching certain compounds it could have a similar profile to a more extracted brew, but be weaker and thus cleaner tasting. Testing tds from the cuppings could establish that as a possibility or rule it out.