jamoke wrote:Wouldn't your La Peppina be a perfect machine for cold high pressure brewing? A gravity-fed lever group machine that needn't even be plugged in: ground coffee in the basket, ice water in the boiler and let 'er rip

Interesting idea, what exactly are you proposing? This is something I could try when I return home, what sort of volumes would you target, demitasse or americano sizes?

I'd think that cold water straight from the Brita in the fridge should work without the ice but it's easy to add ice too. Natural or washed coffee?

I've really enjoyed the iced Chemex batches I made and the last few movies I went to I filled bottles with iced coffee to enjoy during the show. This could be a quick fix.

Chris-

I didn't actually have any specific formula in mind, as my lever machine is pressure-fed rather than gravity. I've also never even tried cold brewing. It's just that the title of this thread combined with the OP's possession of a La Peppina suggested that he might be overlooking an opportunity to try something new with equipment already at hand.

I'll bet a gravity feed lever would be a bit cheaper on ebay if the boiler element was shot.

Hm, why wouldn't you want to use a mypressi Twist for this sort of test?

Um, not that running cold water into coffee in a normal way makes any kind of sense.

This is a discussion about cooler water at somewhat higher pressure, but not as high as they use in labs for forcing extractable compounds out of solids.

There is a pressure that the same tastes we seek at higher temperatures and pressures can and will be extracted at lower temperatures. But they will have added flavors that we would not expect. Some may be considered bad in relation to todays tastes and some may not so much.

I am only asking is the ONLY temperature or pressure we use today, it is the end all or be all of the whole range? I have no answer for that. So I look, I seek, I study other cooking or prep techniques to see if something may cross over.

I may be wrong 9 times out of 10. But I still hope we will be open to the 10th one.

I respect all of you here, and thanks for the time you have given me.

-Cecil

I would like to ask some of the more Lab rat types about how they go about using high pressure chambers with a sudden release of pressure to break down compounds. Can you tell me a bit more on how that physical reaction produces the chemical breakdown of larger strings of molecules?

-Cecil

Interesting. I think the La Peppina, or even the MyPressi for that matter would pressurize the coffee with cold water but the release would be gradual, unlike other experiments that seem to fragment the cell walls by infusing under pressure followed by a sudden release to break the cell walls.

I first read about this on the Kymos blog here that gives a pretty good explanation of how it works, at least with spices. Then I saw Jim Seven posted about it on his blog here with regard to coffee. There are many more people playing in this space, Kymos gives credit to Dave Arnold.

If that's what you're going for, a cream charger is probably going to work better then a La Peppina or MyPressi. I hear the MyPressi Twist is useful for extracting coffee with other solvents besides water because of the easy clean-up, but that's another blog.

Without the sudden break, I think you'll get a poor extraction, but it's easy enough to try. I could even try to take some optical refractometer readings to compare the result with brewed coffee, but it'll have to be paper filtered first.

I have seen Arnolds posts but I missed JimSeven's. And I believe Jim's were more where I was going with this thread.

But using high pressure release to fracture cell walls in decompression is a chem technique that I am looking for the correct term for. I know it is a lab process but I am not sure of the correct name for it. That is what I was fishing for.

Decompression splitting?

Do the pressure changes make for radical local temp changes? Is it ice crystal based shattering of the cell walls? I don't know.

-C

The Kymos blog called it cavitation and links to Wikipedia for a definition here. I'm not sure that quite fits my understanding of the process, but this is out of my field.