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as someone who fell deep into the espresso hole over the past 8 years (from an $800 saeco to a $3000 profitec with a few in between), i see several problems wit

as someone who fell deep into the espresso hole over the past 8 years (from an $800 saeco to a $3000 profitec with a few in between), i see several problems with this. First, CO2 -WILL- enter the brew. There is no way to stop it. This will create carbonic acid and elevate the pH. Which absolutely will impact the flavor. Part of the extraction "dialing in" process is determining the dose, temperature, grind, and duration for a new bean (and as it ages). The last thing you want it so add more acidity to the flavor. Some people do like sour espresso, I do not, and I think I'm in the majority. Second, consistency of pressure. A CO2 canister output pressure changes with temperature and volume. An espresso machine uses a pump (and some a PID) to regulate this. Third, this thing will probably explode after a few weeks. You can't subject plastics to this type of pressure. But OP did suggest using metal in the next version. Fourth, health. Plastic + hot water is bad, add extreme pressure and it is even worse. Kick it up a notch using 3D printed plastic, which is a nowhere near food safe. I'm not too far into the "don't eat out of warm plastic" group, but i'm close. This would concern me. I think it is a cool build. But a Bialeti is sufficient if you don't want to drop thousands on espresso machinery. Also in the running, the early Nespresso designs, not the rotary one. Both will get you into "americano" territory.

Johnny555 3y ago
>Fourth, health. Plastic + hot water is bad, add extreme pressure and it is even worse. Kick it up a notch using 3D printed plastic, which is a nowhere near food safe. I'm not too far into the "don't eat out of warm plastic" group, but i'm close. This would concern me. It doesn’t look like the coffee or water touches the plastic, it goes into a metal Cafelat Robot basket then is tamped with a metal screen on top.
- demondemidi 3y ago
  The screen in between the filter and the chamber top is to prevent grounds from entering up into the chamber, but boiling pressurized water absolutely does flood the entire chamber including the plastic region. (It's not just a wall of pressurized water in nice straight lines, it's a mixture of solids liquids and gasses.) Eg: When I clean my E61 group head, I have to remove a fine mesh filter to get to the brass outflow fitting, and it is still covered with oils from the coffee.
leni536 3y ago
> A CO2 canister output pressure changes with temperature and volume Temperature yes, volume, not really. The CO2 is in liquid state, maintaining its vapour pressure. Although if the starting volume is low, then the liquid could substantially cool down during the extraction and lower the vapour pressure that way. All of this is irrelevant though, as the pressure is regulated down to espresso extraction levels during the extraction. It looks like it's done by hand by eyeballing the pressure gauge, pretty wild. Also not much CO2 enters into a hot liquid, CO2 solubility is drastically down at this temp, as the article notes.
z3dd 3y ago
> But a Bialeti is sufficient if you don't want to drop thousands on espresso machinery. Or 9barista/cafelat robot
searealist 3y ago
> Some people do like sour espresso, I do not, and I think I'm in the majority. It's very hard to find a non-sour coffee where I live, and not much easier to find a non-sour espresso.
- demondemidi 3y ago
  bummer. it can be dialed out, it just takes tame, and sadly the vast majority of baristas use a computer controlled grinder and machine and just push-shots all day long. if you find a place with someone in their 30's with weird facial hair or tattoos pulling shots, they're likely to invest more of their personality in understanding espresso, which is better for your. tell them to pull the shot "lungo" (longer) so you get more of the bitter tail. or tell them increase the boiler temp.

Johnny555 3y ago

>Fourth, health. Plastic + hot water is bad, add extreme pressure and it is even worse. Kick it up a notch using 3D printed plastic, which is a nowhere near food safe. I'm not too far into the "don't eat out of warm plastic" group, but i'm close. This would concern me. It doesn’t look like the coffee or water touches the plastic, it goes into a metal Cafelat Robot basket then is tamped with a metal screen on top.

demondemidi 3y ago
The screen in between the filter and the chamber top is to prevent grounds from entering up into the chamber, but boiling pressurized water absolutely does flood the entire chamber including the plastic region. (It's not just a wall of pressurized water in nice straight lines, it's a mixture of solids liquids and gasses.) Eg: When I clean my E61 group head, I have to remove a fine mesh filter to get to the brass outflow fitting, and it is still covered with oils from the coffee.

leni536 3y ago

> A CO2 canister output pressure changes with temperature and volume Temperature yes, volume, not really. The CO2 is in liquid state, maintaining its vapour pressure. Although if the starting volume is low, then the liquid could substantially cool down during the extraction and lower the vapour pressure that way. All of this is irrelevant though, as the pressure is regulated down to espresso extraction levels during the extraction. It looks like it's done by hand by eyeballing the pressure gauge, pretty wild. Also not much CO2 enters into a hot liquid, CO2 solubility is drastically down at this temp, as the article notes.

z3dd 3y ago

> But a Bialeti is sufficient if you don't want to drop thousands on espresso machinery. Or 9barista/cafelat robot

searealist 3y ago

> Some people do like sour espresso, I do not, and I think I'm in the majority. It's very hard to find a non-sour coffee where I live, and not much easier to find a non-sour espresso.

demondemidi 3y ago
bummer. it can be dialed out, it just takes tame, and sadly the vast majority of baristas use a computer controlled grinder and machine and just push-shots all day long. if you find a place with someone in their 30's with weird facial hair or tattoos pulling shots, they're likely to invest more of their personality in understanding espresso, which is better for your. tell them to pull the shot "lungo" (longer) so you get more of the bitter tail. or tell them increase the boiler temp.