3 ms·

Persistent foam (crema) forms due to the presence of trapped CO2 in the grind, rather than just the high pressure. Espresso grind is special. It's not just fai

Persistent foam (crema) forms due to the presence of trapped CO2 in the grind, rather than just the high pressure. Espresso grind is special. It's not just fairly fine grind, it's a mix of fine, moderate and coarse grinds that are packed together. If you are to try and use just an uniformly fine grind for espresso, the machine will have very hard time extracting from it - literally a drop a second instead of a flow.

pandaman 7y ago
>Persistent foam (crema) forms due to the presence of trapped CO2 in the grind, rather than just the high pressure. If this had been true, you could just toss coffee grounds into hot water and it would foam up. > If you are to try and use just an uniformly fine grind for espresso, the machine will have very hard time extracting from it - literally a drop a second instead of a flow. Really? Any uniformity in grind will block machine? Could you explain physics behind such phenomenon please?
- huhtenberg 7y ago
  >If this had been true, you could just toss coffee grounds into hot water and it would foam up. Jeez, dude... That's EXACTLY what happens. It's called a "bloom". Here, first hit in Google - https://www.roastycoffee.com/coffee-bloom/ https://www.roastycoffee.com/coffee-bloom/ >Really? Any uniformity in grind will block machine? Could you explain physics behind such phenomenon please? Yes, really. Give it a try. Better yet, read a book on a subject. Something like Blue Bottle's intro into coffee making.
  - pandaman 7y ago
    I wouldn't trust coffee makers as your source of physics and chemistry data. Instant coffee "blooms" too, it's not espresso foam and it's not caused by "captured CO2". Highly uniform ballbearings do not restrict flow any more than other particles of comparable sizes. And, not mentioned by you yet, but my favorite coffee people "fact" - distilled water does not cause more corrosion than tap water.

pandaman 7y ago

>Persistent foam (crema) forms due to the presence of trapped CO2 in the grind, rather than just the high pressure. If this had been true, you could just toss coffee grounds into hot water and it would foam up. > If you are to try and use just an uniformly fine grind for espresso, the machine will have very hard time extracting from it - literally a drop a second instead of a flow. Really? Any uniformity in grind will block machine? Could you explain physics behind such phenomenon please?

huhtenberg 7y ago
>If this had been true, you could just toss coffee grounds into hot water and it would foam up. Jeez, dude... That's EXACTLY what happens. It's called a "bloom". Here, first hit in Google - https://www.roastycoffee.com/coffee-bloom/ https://www.roastycoffee.com/coffee-bloom/ >Really? Any uniformity in grind will block machine? Could you explain physics behind such phenomenon please? Yes, really. Give it a try. Better yet, read a book on a subject. Something like Blue Bottle's intro into coffee making.
- pandaman 7y ago
  I wouldn't trust coffee makers as your source of physics and chemistry data. Instant coffee "blooms" too, it's not espresso foam and it's not caused by "captured CO2". Highly uniform ballbearings do not restrict flow any more than other particles of comparable sizes. And, not mentioned by you yet, but my favorite coffee people "fact" - distilled water does not cause more corrosion than tap water.