Grind Sifting for Brewed Coffee - Page 7

Coffee preparation techniques besides espresso like pourover.
jbviau
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#61: Post by jbviau »

varnex wrote:If you're sifting for anything besides espresso, 300 microns works great. Anything ~500µm+ ends up wasting a lot of coffee and makes achieving high extraction more difficult. (My 450 micron sieve eats up around 25% of the grinds)
Thanks. I can imagine. Let's not even talk about my 850-micron #20 sieve then... 8)

I'm very tempted to pull the trigger on that #50.
"It's not anecdotal evidence, it's artisanal data." -Matt Yglesias

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TomC
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#62: Post by TomC »

jbviau wrote:A question to those of you with some sifting experience: would 300 microns (#50) be about right? I've got a bead on a vintage sieve, and 300 seems close enough to what's usually talked about (e.g. ~250 microns). Thanks in advance for any help.
I have 1000, 475, 425 and 250 micron sieves, and here's a painfully long thought stream on the topic of fines....

Although I love contemplating on the issue of grinders and particle distribution, fines, etc, for the time being, I can't see much conclusive info that sieving coffee will prove much, other than the presence of dull burrs in need of sharpening or replacement. The rest just seems to be head scratching to me. Not that I don't love doing it, but I won't pretend to know what I'm actually achieving, other than a subjective opinion of the coffee tasting better or different.

My thoughts on sifted/sieved coffee continue to be challenged by my own subsequent tests and a fair bit of "internal dialogue", but it's hard to nail much down conclusively without a lab full of equipment, so it's mostly conjecture. One thing I'm certain of; it's not a simple thing, although it appears to be at first glance. I've had multiple infusion brews that I've sieved before brewing, removing 5% of the total pre-sieved mass, still resulting in barely noticeable changes in levels of sediment in the bottom of brewing device, (French Press, Sowden Brewer, etc) but it does considerably alter the clarity in terms of flavor separation.

Sieving a sample of ground coffee gives me a better idea about grind consistency than it does tell me anything about the amount of fines a particular grinder produces. Mainly because the individual grains of ground coffee are easier seen and examined once the flour like "fines" are shaken free from the sample. Using my Ditting 1203 with new burrs, I can sift a sample of coffee and examine the results, which appear just like industrial ground coffee, the extremely consistent grind you'd find in a typical can of Foldgers, for instance, that are likely produced with rolling mills instead of burrs. So, I'm starting to think that my sieving practice is more useful for determining grind evenness and burr wear, than anything else.

This is the stuff I'm pretty much certain of, however.

1) Every grinder produces fines, it's impossible to grind coffee without them.
2) I can't, with my rudimentary equipment, properly define what I sieve out as "fines", I subjectively believe true "fines" are far smaller than the flour like particles I'm sieving out.
3) Particles at this size, appear to be affected by static forces just as much as mechanical agitation, I can, just by the naked eye, look at a sample that I'm mid-way thru sieving, and see very fine flour like material clinging to the larger, more consistent sized grains of coffee in my sample. I can take a 20g sample of ground coffee, shake and rattle the heck out of it aggressively for 30 seconds, and separate out about 1.5g of flour like coffee powder. I dump that powder out and give it 5 or so more shakes and nothing appears to be separating anymore, the catch cup at the bottom remains empty. But if I continue on, continuing to shake like crazy, it will again start to separate more powder from the sample. And I can hold the sieve with the upper lid still on, to prevent spilling, but without the lower catch cup, and tap the whole thing rather aggressively against a hard surface, and bang off any static clung coffee powder from the bottom of the screen. Even then, however, I can put the catch cup back on and rattle and shake it some more, and end up with new powder in the bottom of the cup. Which leads me to think that....
4) The act of mechanical agitation with a sieve can by some minute force or another, either wear away at small coffee particles, or slightly separate fine intra-cellular material from within fractured cellulose walls that are partially open, i.e. banging it around with a sieve doesn't just simply separate it out into a tray, but it seems to possibly be producing more of it from within these fractured bits of cellulose cell walls losing more of their contents.
5) And the important thing about the point above is, I don't think the particles I'm removing in that instance are "fines" but rather, very small bits of the soluble material I want in the cup, not sieved out of it!

All that being said, I can on average, take a un-sieved sample of coffee and brew it at a max of a 15:1 brew ratio. It will make for a richer more flavorful cup, but any higher of a brew ratio than this, and I risk increasing bitterness or astringency. But I've done several cups brewed at a 14:1 ratio of sieved coffee, and have been blown away by the depth of flavors that are still separate and defined, without the aforementioned bitterness or astringency creeping in.

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Eastsideloco

#63: Post by Eastsideloco »

I'm very tempted to pull the trigger on that #50.
If you just want to experiment with the process of and results obtained by sifting ground coffee for brewing methods, the sieve you are looking at should work for this purpose. That is a good sieve size for brewed coffee methods in the sense that it is within the range that a competition barista might use to sift out fines. If the sieve doesn't include a lid and a pan, you'll have develop some alternative to shaking. Presumably a brush could be used to move the fines down through the sieve.

Tom's experience rings true. Part of the challenge of adding a sieve to your routine is that you have just introduced another variable (in addition to grind size, water temperature, extraction time, etc.) that you have to manage and can potentially screw up. Plus it's a whole new learning curve. It might generally improve your results with one brew method, while consistently producing a underwhelming cup with another method. It might improve one cup while having a deleterious effect on another. It's hard to connect the cause and the effect, but it is another tool at your disposal.

If nothing else, it provides interesting insights into particle distribution and the role of fines. For example, I eventually stopped using the coffee sieve with my aeropress because I was counterintuitively getting more grit in the cup after sifting the grinds. With a normal distribution of grind sizes, I believe the fines in the coffee bed prevented micro fines from reaching and passing through the filter.

I go back and forth on using the sieve these days. On the one hand, I still put coffee through a sieve for brewing a siphon pot with a glass rod filter to prevent stalling. On the other hand, I don't use a sieve for siphon brewing using paper, metal or cloth filters because it either doesn't improve the cup or seems to make it more difficult to get a good cup. Sometime I use the sieve with my Kalita wave; sometimes I don't. I've had good cups both ways without even changing the grind setting. So if you're using the right coffee to water ratio for the brewing method (and have all the other variables dialed), the results are more in the noise than a determining factor in the cup.

It still makes sense to me that a skilled barista with a highly tuned palate can use a coffee sieve to fine tune a championship cup. While the changes in the cup are subtle and likely beyond the average person's ability to detect a difference, the judges are presumably above average tasters.

jbviau
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#64: Post by jbviau »

I enjoyed those thoughtful replies. Thanks, you all. The test sieve is en route. It's a smaller 3-in. model, just like the #20 I've had for a while. I find that size easy to work with for single-cup brewing and home use.
TomC wrote:...I'm starting to think that my sieving practice is more useful for determining grind evenness and burr wear, than anything else...
This is what I'm after, mainly, plus some light experimenting with flavor clarity. Re: grind consistency evaluation, the few times I've sieved in the past I did notice what you mentioned, i.e. the more you shake the more "fines" you get. Some sort of consistent, repeatable agitation routine seems important if the goal is to compare grinders.
Eastsideloco wrote:...I eventually stopped using the coffee sieve with my aeropress because I was counterintuitively getting more grit in the cup after sifting the grinds. With a normal distribution of grind sizes, I believe the fines in the coffee bed prevented micro fines from reaching and passing through the filter.
This is completely in line with what I've read especially on CG in the main Aeropress thread. Sounds right.
"It's not anecdotal evidence, it's artisanal data." -Matt Yglesias

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happycat

#65: Post by happycat »

If you are sieving and wasting a lot of coffee, try adding the fines nearer the end of brew time. You get the benefit of extraction without over extraction.
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TomC
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#66: Post by TomC »

Coffee waste, is unfortunately, subjective.

And when I sieve, on the best examples, it amps up the clarity of individual flavor components (on coffees that are dynamic and not very uniform, but absolutely shine in one specific component or flavor, like a good Geisha). Adding fines back in will be time consuming, and leave me with a muddy cup again. And I've tried it myself several times, but still find that it quickly extracts and can lead to a bitter cup unless it's consumed very quickly.

jbviau
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#67: Post by jbviau »

Here's the new addition to my kit:

Image

Back to one of the points discussed earlier, let's say I'd like to use the sieve to evaluate relative grind consistency in comparing several different grinders. Doing so seems to presuppose the ability to match the grinders being compared in terms of grind "setting" to start with. What's the best way to do that other than eyeballing (too subjective)? Apologies if it's been discussed elsewhere on HB (would appreciate a pointer in that case). My first inclination would be to use a consistent-as-possible pourover routine and rely on drawdown time as a guide, e.g. adjust the grinders' settings until their coffee (unsieved) gives me equally long pourover drawdowns and then sieve to compare. Hmm, now that I've written that out I'm unsure if it makes any sense. Little help, please?
"It's not anecdotal evidence, it's artisanal data." -Matt Yglesias

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jbviau
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#68: Post by jbviau »

Anyhoo, about matching grinders for "setting" to the extent possible prior to testing, I did see this from the Titan Grinder Project:
RapidCoffee wrote:The samples were prepared by adjusting each grinder to yield a specific type of shot on one espresso machine. In this case, a ridgeless double basket was dosed with 19g coffee, and the grind adjusted to yield a 60ml shot in 30 seconds on a QuickMill Vetrano. After adjustment, three samples were ground on each grinder. Sample size ranges from 10g (1/8 cup) for wet analysis to 40g (1/2 cup) for dry analysis
Doesn't help for brewed coffee, but it's the same general idea.

I find it hard to imagine that this subtopic is too geeky for HB. 8) It's certainly not *off*-topic for the thread IMO; lovers of brewed coffee shouldn't object to the pursuit of the best possible cup, and finding the grinder that helps give that to you is of obvious importance.
"It's not anecdotal evidence, it's artisanal data." -Matt Yglesias

jbviau
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#69: Post by jbviau »

Well, what sent me down this path was the experience of having a week with a Comandante C40 (from Able's first batch) and trying to compare it to the LIDO in the cup (build quality issues re: the former aside). For taste comparisons, I did my best to match the grind I use with my Trifecta and then brewed back-to-back cups of a QED Honduras I had on hand while varying only the hand grinder used. Coffee from the C40 was inferior to that from the LIDO in terms of aromatics (muted), body (thinner; cup structure fell apart more while cooling), and flavor (muddier profile; edgier). However, I'm not 100% confident that some of the difference wasn't due to the C40 not being as well dialed in. This was before the sieve arrived.
"It's not anecdotal evidence, it's artisanal data." -Matt Yglesias

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TomC
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#70: Post by TomC »

I found basically the exact same thing, as I have the first gen C40 from Able as well. I finally made the decision that it's just ruining my coffee, because the grind variability is so inferior and I don't even want to take it to work with me anymore. The brews fell flat within minutes of brewing, going towards cardboard and flattened flavors. All the beautiful aromas are heavily muted. But it was either this, or not have coffee after 7:30 AM on the days I work. I found if I were to grind a very freshly roasted coffee right before heading out the door, on my big Ditting, I could brew it as soon as I got to work and still have great coffee. But taking several small batches of coffee meant I was drinking staled coffee after 8:30-ish.

I'm of the belief that the first gen C40's can't even be dialed in correctly. The burr alignment is so sporadic that it can't be tuned very well. Even at coarse settings it produces tons of variable particle sizes and fines. Finer settings don't seem to change this very much, but the fines quantity seems to increase. I think you'd need several sieves, and way more time and effort than it's worth, to arrive at a proper, medium grind size with the C40. So, one sieve won't help much.