TheJavaCup77 wrote:Solutes can extract chemicals from solubles at higher rates of extraction when pressurized (I.E Pressurized Percolation)

I'm looking to build a 30 bar SBDU for 15 second extractions.

Anyone seen any electrically controlled
30 bar industrial pumps small enough to fit in a SBDU?

Why limit yourself, just try for about 100 bar and 5 seconds.

5 seconds is a pretty slow goal when one can instead use explosives instead of pump pressure.

TheJavaCup77 wrote:Solutes can extract chemicals from solubles at higher rates of extraction when pressurized (I.E Pressurized Percolation)

Not true of solids, which is what coffee is.

TheJavaCup77 wrote:I'm looking to build a 30 bar SBDU for 15 second extractions.

9bar came to being the norm for no reason other than because it was the fastest.

Fractured puck in the portafilter?

And now it seems you'd need to tamp as hard as heck to actually compress the grinds hard enough.

Yet too fine of a grind will give an extremely slow pour for an over extracted espresso or worse yet choke the machine.

Maybe start from 13 bars and go higher from there and see how things work.

Hoping not to get a too slow pour rate or even chocking the machine yet even avoiding the puck fracture and channeling (Inconsistent
extraction?).

Espresso means express in italian and its because they want things fast like their Lambo's that they would conceive the idea to use pressure and finer grind sizes to stretch the speed of extraction till they could get a properly extracted coffee in 30 seconds.

Maybe i'm too tempted to build a Bugatti of espresso machines???

aecletec wrote:5 seconds is a pretty slow goal when one can instead use explosives instead of pump pressure.

Actually that's true. Perhaps a machine with a small blasting cap on the coffee, electrically detonated when a button on the machine is pressed.

I reckon we would get it down to about 1s.....free plastic underpants supplied with each blasting cap conversion kit.

endlesscycles wrote:9bar came to being the norm for no reason other than because it was the fastest.

I wonder how that's changed with pre-ground coffee capsules and pods. I think the exploration into higher pressure extraction is targeted at these sorts of push-button, pre-ground machines.

~

I wonder if you could put some sodium metal in with the ground coffee for some explosive results when the water hits the puck. Make sure you're wearing ballistic goggles, better yet, don't try that at home.

yakster wrote:I wonder how that's changed with pre-ground coffee capsules and pods. I think the exploration into higher pressure extraction is targeted at these sorts of push-button, pre-ground machines.
..

It's not about pressure. Pressure doesn't affect extraction. Got it?

Grind size and temperature do. Flow rate does as well. Espresso is done at pressure for a higher flow rate. Optimum extraction at the lowest time occurs with finest grinds and fastest flow rate.... it tends to be between 8-9bar for typical coffees and doses.

no this isn't what we meant, at least I don't believe so. It's sort of likened to trying to boil an egg in 10 seconds, simply not going to give good results.

Pressure is VERY important to extraction, but how it's applied and how much is applied throughout the shot is what matters. 9 bar is just a happy average.

Others in the industry (LM & Illy) have been researching the benefits of higher espresso extraction processes. Although I found this hard to believe of higher pressures greater than 9 BAR benefiting espresso extraction esp with only 7gram shots! Yet I haven't been able to qualitatively try a taste of this Caffè Firenze of course!

Caffè Firenze: A New Extraction Technology From La Marzocco & Illy article:
http://sprudge.com/caffe-firenze-new-ex ... -illy.html

Fact: Here is a article about the idea/process of using up to 20bar of pressure for espresso made by a method termed: Caffe Firenze.

This was done by Illy and La Marzocco already and they have a working prototype using compressed air into a modified LM Strada EP with a higher pressure group chamber and a modified portafilter with a valve in the handle!

Alex Bernson (Excerpt 1) wrote:Caffè Firenze uses a combination of compressed air and a standard espresso machine pump to extract espresso at 20 bar with a partially-sealed high-pressure brew chamber. The resulting shot has an intense amount of super light and silky crema, and the claim is that it produces more sweetness and emphasizes the aromatics."

Alex Bernson (Excerpt 2) wrote:The actual extraction of Caffè Firenze goes through four distinct stages, over the course of about a minute:

1. The sealed portafilter is locked into the heated brew-chamber, and compressed air is added, bringing the chamber to 15bars of pressure.

2. Water at standard espresso temperatures is added to the brew chamber, bringing the pressure to 18 bar, and then the valve is opened for a second and then closed to "pre-infuse" the coffee.

3. The closed chamber is brought to 20 bars of pressure with the addition of more water.

4. The valve is opened and the shot is extracted by the compressed-air escaping."

Note: Excerpt quotes {1 & 2} are courtesy of Sprudge.com article dated October 25, 2013 by Alex Bernson.