# Matt Perger's Sifting Coffee Experiment



## the_partisan (Feb 29, 2016)

I saw this on Barista Hustle:






Seems like another one of his pseudoscience theories to me. I have a hard time believing in the "water doesn't penetrate into the inside of the grounds" idea when grinds are >250um though I guess there's some upper limit on how large particles can be to hit a decent extraction. But using drip it's possible to hit 20%+ extraction yield using very coarse grinds, like the coarsest setting on your grinder.


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## MWJB (Feb 28, 2012)

22.5% immersion yield isn't close to "everything". It could be a perfectly normal level of extraction for a French press, AP, or Clever brew.

I'm curious as to how you clarify & serve a brew made with only sub 500um particles? Turkish coffee has been around centuries (and tends to be a higher extraction than Perger saw here), but it can be silty and you tend to lose some of the cup to avoid getting grinds in your mouth.

So, by using a very fine grind you can get a typical level of extraction in a few seconds, but what's the advantage if you spend as long as a drip brew filtering out the silt?

Lastly, always a bit suspicious of extraction claims based on 1 coffee. You need a few origins to determine an average, a 5% spread across my immersions is fairly normal.


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## the_partisan (Feb 29, 2016)

Also cupping is one of the hardest methods to extract, due to rapidly declining temperature. I think it will already hit something like 50C after 10mins? It would be interesting to repeat the experiment at a constant temperature and likely the difference won't be so dramatic? I'm kind of bothered by their method of doing one random experiment and then drawing all sorts of conclusions from it.

Turkish coffee can be quick to brew (assuming you don't have to use a hand grinder







) as you are using only 150ml water or so and warming it up. It can taste quite sweet and well rounded but you still need to wait several minutes for the silt to settle so that it can be drinkable. About 1/3 won't be drinkable due to the silt at the bottom. In the end a drip brew becomes more practical, but I do enjoy the mouthfeel of Turkish coffee sometimes, usually after a meal (probably because I'm Turkish







).


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## MWJB (Feb 28, 2012)

the_partisan said:


> Also cupping is one of the hardest methods to extract, due to rapidly declining temperature. I think it will already hit something like 50C after 10mins?.


I found ~65C after 9min, with a break at 4min, 7oz ceramic cupping bowl 12g coffee, 200g boiling water. Break vs no break didn't seem to make a big difference in temp or extraction. 57C after 15min.

~80c after 15min with a 3cup glass French press, covered, no break (same coffee & water weights).


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## the_partisan (Feb 29, 2016)

If I remember from my chemistry classes with gasses every 10C increase means double reaction speed though I'm not sure how it applies to coffee brewing. It might be that though the temperature has far greater effect than grind size for immersion brews, given long enough time? How did the extraction of your two brews compare?


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## Step21 (Oct 2, 2014)

I think many of us worked out for ourselves (or rather with @MWJB 's help) that grinding finer than the french press "norm" produces better immersions and cuppings. He's a bit late to the party on this one. Old news....


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## MWJB (Feb 28, 2012)

the_partisan said:


> If I remember from my chemistry classes with gasses every 10C increase means double reaction speed though I'm not sure how it applies to coffee brewing. It might be that though the temperature has far greater effect than grind size for immersion brews, given long enough time? How did the extraction of your two brews compare?


I ground a bit coarser than usual for these brews (2+0 on feldgrind, ~500um avg), I was looking more at temp, but all brews were 19.9% to 21.3% immersion, irrespective of brew time. Not really a big enough spread to imply anything re. brew temp.

There were 3 brews per condition.

Ceramic bowl, break at 4min, TDS @ 9min

Ceramic bowl, no break, TDS @ 9min

Ceramic bowl, no break, TDS at 15min

Ceramic bowl, no break, covered with ceramic lid, TDS @ 15min

Glass FP, no break, covered with lid, TDS @ 15min


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## MWJB (Feb 28, 2012)

Step21 said:


> I think many of us worked out for ourselves (or rather with @MWJB 's help) that grinding finer than the french press "norm" produces better immersions and cuppings. He's a bit late to the party on this one. Old news....


CBI published similar 10yrs before I was born, so very old news


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## Step21 (Oct 2, 2014)

MWJB said:


> CBI published similar 10yrs before I was born, so very old news


Which makes it odd that so few do it. If you look at most online info and coffee publications the standard advice is still very much to grind coarse for French press. Even with aeropress a lot of "advice" still has updosing to cater for less extraction rather than grinding finer with a standard dose. Maybe because it's Matt Perger people will listen.


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## Stevebee (Jul 21, 2015)

Step21 said:


> Which makes it odd that so few do it. If you look at most online info and coffee publications the standard advice is still very much to grind coarse for French press. Even with aeropress a lot of "advice" still has updosing to cater for less extraction rather than grinding finer with a standard dose. Maybe because it's Matt Perger people will listen.


I wonder if it's because of the coarseness of the standard metal filter that is used. Maybe in the belief that too fine won't be filtered. If you wait for it to settle and and press slowly the size of the mesh is irrelevant any way but who knows.


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## fluffles (Sep 4, 2012)

Step21 said:


> Which makes it odd that so few do it. If you look at most online info and coffee publications the standard advice is still very much to grind coarse for French press. Even with aeropress a lot of "advice" still has updosing to cater for less extraction rather than grinding finer with a standard dose. Maybe because it's Matt Perger people will listen.


Updosing would cause more under extraction, not cater for it


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## MWJB (Feb 28, 2012)

fluffles said:


> Updosing would cause more under extraction, not cater for it


Won't make much difference with immersion, grind size is a bigger driver for normal brew ratios (55-75g/L)...an issue maybe if you go bonkers high.

More of an issue for percolation.


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## the_partisan (Feb 29, 2016)

Step21 said:


> Which makes it odd that so few do it. If you look at most online info and coffee publications the standard advice is still very much to grind coarse for French press. Even with aeropress a lot of "advice" still has updosing to cater for less extraction rather than grinding finer with a standard dose. Maybe because it's Matt Perger people will listen.


Anyone remember this?














But yes unless you are willing to wait 10+ mins you're better off updosing..

Still with the modern methods you can get silt in the cup if you're grinding finer than necessary, especially when pouring the last cup out.


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