more pressure wackiness

So I've pulled a couple dozen shots already today. And on all where I did my part (i.e. the grind was right, the temp surf was right, dose and distribution were right) I got the desired and previously elusive "clarity of flavours."

Now... I'm very happy about this. Don't get me wrong. I had one of the best shots I've had in a very very long time this morning as well as a truly amazing cappuccino.

But I've learned something along the way.
Sometimes you don't want clarity.

While the shots I've had of Hairbender and some other coffees have been amazing and brilliant and beautiful - the shots of a couple other coffees have been far inferior to what I'm used to getting on this machine. With the clarity of flavour, unfortunately, has come a lack of balance and the sudden emergence of flavours in the coffee that are not amazing and brilliant and beautiful. With these coffees, the resulting espresso has been jarring and jagged on the palate.

I think it might be a great thing to have clarity of flavour in a coffee where all of the component beans are very good tasting and very high quality. If, however, the blend is "hiding" an inferior bean or two in the mix (perhaps to provide enhanced crema or improved colour or the like), even if the blend is incredibly carefully constructed so as to emphasize only the positive attributes of that bean and to obscure the negatives... once you get the sort of definition and transparency I'm talking about those hidden traits pop right out into the open.

Now this is an interesting discovery and a compelling concept!! And it might fit into some of my theories about Italian espresso, natural coffees, fine grind/light tamp, the pre-infusion on E61 based machines and the default declining brew temp of such machines. Hmmm...

I'm starting to see a potential diverging evolutionary path here. And in the future of the one I want to move down is a espresso machine with some sort of computer controlled linear hydraulic piston instead of the traditional rotary pump. Couple this with computer control of brew temp and temp profile as well as a bunch of the other innovations of late... Anyone listening out there in techie world?

The newest Portafilter.net podcast is up and I'm interviewed on it. It was fun but damn do I sound like a seriously wacky mad scientist. Sigh... Oh, for those who've heard it, my eye has some discoloration but it's not actually black as it turns out.

Oh... and finally, I did not "invent" this whole water pressure/brew pressure thing and I'm not the first person by a long shot to come up with the idea that it is of importance. Folks like David Schomer figured that out years and years ago.


eureka moment

I may have had a breakthrough today.

I've been trying to understand a factor that I prize in great espresso - the sense of "clarity" of flavours. By this I mean that experience you sometimes get in a great shot where you can taste all the component beans and all the component flavours of all those beans - where there is this sense of "definition" of flavour in the cup. This is something I particularly value in truly complex espressos like the Hairbender or the Hines Espresso blend.

Ever since my first home machine review (of the Mia) I've been obsessing over this elusive characteristic. I discovered that I was not able to get any sense of clarity with the Mia or the Astoria. This is not to say that the espresso didn't taste good. But I was missing that weird definition.

I then came to the realization that I had rarely experienced this clarity in shots from commercial machines either. In fact, the only machines that seemed to be able to produce this were the temp-stabilized top commercial machines like the Synesso or a temp-stabilized Marzocco or Mistral. But... that being said... I also had noticed that there were examples of such machines where I was not able to get that clarity - so it couldn't just be temp stability. Hmmm...

I'm currently reviewing a home machine that seriously kicks ass (the Fiorenzato Briccoletta). Now, this machine has a couple of unique characteristics. First - it has a Procon rotary pump like the big boy commercial machines. And secondly - it is plumbed in. Now... as I'm reviewing it, I decided to run it off bottled water. But I didn't want to risk damage to the machine, and also didn't want to have to pay for tons of 5 gallon bottles of Crystal Geyser. So it's hooked up to a FloJet pump system (to mimic line pressure) and a Everpure Filtration canister.

I've been working really hard (with tons of advice and assistance from knowledgable folks who understand Heat Exchanger machines far better than I do) and have reached the point where I can be very accurate not only on brew temp but on temp profile. Thanks to some research by Dan Kehn, I've become able to "mimic" the temp profile of a Linea. But I still was not getting the clarity I'm looking for. Damn it!!

Today I went to reset the brew pressure on the machine as it's been running too high (10.25 BAR instead of 9.25 BAR). After doing so, I pulled a shot that was damn near perfect. Incredible clarity. Wow!! Hunh?

So I started to play around with the setup trying to understand it. In doing so, I came to an amazing discovery. If I had the pump running straight out of the water tank I could see "flutter" in the brew pressure while monitoring it. If I had the pump running off the FloJet but without the water filtration I could still see the flutter. In addition, shots pulled both of these ways lacked the desired clarity.

But when the FloJet and the water filtration unit were combined, the flutter went away and the clarity returned.

The light goes on...

I think, or believe, that the filtration unit is acting as a "dampener" of sorts. And I think, or believe (or perhaps hope) that this clarity is a result of control of the brew temp profile and a consistent brew pressure.

Man... if this is true it's a very cool thing!