Why/how does filter paper block/trap coffee oils?

In summary, paper filters block cafestol and kahweol, which are both functionalized polycyclic molecules. These molecules have a molar mass around 315, which makes them too large to pass through a cloth filter. However, oil and water are two liquids that are immiscible, so they will not mix together. This prevents the cafestol and kahweol from getting into the brewed coffee.
  • #36
BillTre said:
You could always use no filter medium and completely remove that issue.
  1. Brew your coffee with the grounds suspended in a container of heated water for some period of time.
  2. Let the grounds settle out (or centrifuge them if you are in a hurry.
  3. Pour off the supernatant (the coffee), leaving the grounds behind in the original container.
  4. Enjoy.
This is how coffee is brewed in very traditional cultures in Africa. I think even Turkish coffee is brewed this way. However this is probably a bit limited as far as separating enough oil from the finished product.
 
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  • #37
BillTre said:
You could always use no filter medium and completely remove that issue.
  1. Brew your coffee with the grounds suspended in a container of heated water for some period of time.
  2. Let the grounds settle out (or centrifuge them if you are in a hurry.
  3. Pour off the supernatant (the coffee), leaving the grounds behind in the original container.
  4. Enjoy.
However the idea of the centrifuge is brilliant, I must say.
 
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  • #38
moriah said:
However the idea of the centrifuge is brilliant, I must say.
A bucket on a rope twirled over your head is a centrifuge.
 
  • #39
BillTre said:
A bucket on a rope twirled over your head is a centrifuge.
Your putting images in my head. Yeah but on that note, putting the brewed coffee in a jar and shaking it for a few minutes would probably have close to the same effect.
 
  • #40
moriah said:
Your putting images in my head. Yeah but on that note, putting the brewed coffee in a jar and shaking it for a few minutes would probably have close to the same effect.
Centrifugal separation works, but for emulsions the required acceleration may be a bit higher than what can be provided by simple manual means...

Since it's already flirting with sci-fi, then maybe some ultrasonic magic?
 
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  • #41
Rive said:
Centrifugal separation works, but for emulsions the required acceleration may be a bit higher than what can be provided by simple manual means...

Since it's already flirting with sci-fi, then maybe some ultrasonic magic?
I agree with the bit about emulsion. I would try shaking the liquid and then filtering whatever is separated on top.
 
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  • #42
BillTre said:
You could always use no filter medium and completely remove that issue.
  1. Brew your coffee with the grounds suspended in a container of heated water for some period of time.
  2. Let the grounds settle out (or centrifuge them if you are in a hurry.
  3. Pour off the supernatant (the coffee), leaving the grounds behind in the original container.
  4. Enjoy.
Description of process would be like "French Press" brewed coffee.
( I do not drink coffee done that way; I use filter-drip through paper. )
 
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  • #43
Maybe the answer or explanation to my original question is really too complicated. I could then just accept the fact (or my common experience) that brew time of African coffees using hot-water paper drip-filter takes much longer than brewing coffees of most other origins.
 
  • #44
symbolipoint said:
Description of process would be like "French Press" brewed coffee.
( I do not drink coffee done that way; I use filter-drip through paper. )

This (https://www.bodum.com/us/en/1928-57-chambord) is among my favorite coffee brewing
devices:

1641249526853.png
 
  • #46
Due to posts #44 and #45, I should try using or test using a french-press device. I tried once a couple years ago but did not like the method nor results so continued with filter-drip.
 
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