2) The bigger challenge is actually brewing large amount of ristrettos/espressos, not necessarily concentrating it.
3) just sounds way too complicated to me to rival/equal soluble coffee
Edit: haven't really looked into any of these as a feasible option for us.
I'm kinda surprised you say that brewing the ristrettos are the hard parts. I know that centrifugal brewing is all the rage these days (as siphon, pour-over, and espresso were before), but it seems like automating espresso is a solved problem. Are there no industrial-scale burr grinders?
I think the biggest problem would be tamping and getting that to be consistent.
Is there anyone who needs industrial scale espresso?
As far as we could find, there is no common solution for industrial scale espresso. If someone has one, please post it here. This was a personal obsession of mine last spring - "How does this not exist?!?"
Kalle is the coffee expert, but as the 'non-coffee guy', I have no idea why this wouldn't exist - I would have thought someone out there would need it?
1) Pouring a ristretto into liquid nitrogen. At reconstitution time, put into boiling water and stir. Issue: Cold coffee, potential colloid separation -- solutions might include some kind of stabilizer
2) Taking a ristretto and removing water content to concentrate it, and then pull a vacuum on it and package it. Said package can then be opened and dissolved in boiling water. Issue: Complexity. Removing the water can be complicated, pulling a vacuum on it, and then heating it while at vacuum is hard.
3) Coffee puck: Take traditional coffee, and put it into a permeable membrane that when exposed to water above a certain temperature is permeable. When that temperature drops, it stops being permeable. Problem: Said polymers were hard to find.