Saturday, November 25, 2006


the vibiemme: attempting to adjust the p-stat

ok, as promised, i bounced into the kitchen to try to adjust the temperature of caesar vibiemme down from its factory default of 200 to 194 or even 190 degrees f (88c +/- 2), per the italian standard for espresso brewing.

long-time readers know that proper temperature is crucial in espresso extraction, and serious artisan roasters will tell you the temperature at which they intend their coffee to be brewed.

if you buy a specialty bean and the roaster can't tell you his preferred temperature as well as why he or she prefers that temperature, you might want to reconsider the roaster. . .it shows that roaster isn't really involved in the important details of the craft. . .

most contemporary american espressi are generally created for something like 200-202 in accordance with the general scaa standards; mark inman's espresso 0 seems to be an exception, in that it is made for 198-200.

this is a huge difference between italian coffee and american, frankly. in fact, the italians will tell you that the specs are so different, albeit it in ways that at first might seem minor, that it amounts to creating another beverage altogether, chemically and thus taste-wise.

this is why the italians are so set on trying to standardize what they consider the proper espresso to be. they believe an espresso should be a blend (miscela) with a brazil or mild coffee as its base ("mild" here in the technical coffee jargon meaning "an arabica not grown in brazil") -- illy i believe is using some indian coffees now along with brazils.

and that it needs to be brewed at this lower temperature.

so many of the finer artisan espressi i'm drinking now use these super-premium brazils, and i frankly think they often do benefit from the lower temperature of the italian standard. i mean, i always love the coffee in rome and north, so why not try to brew that in my fancy high-end espresso machines?

at this point the american pro baristi who are reading this are probably having heart attacks, but what can i say? the coffee in italy is for the most part fantastic. . .so why not try that out?

hx or heat-exchanger machines like caesar and carlos expobar have internal temperature controls called "pressure stats" or p-stats. these are mechanical devices that control the pressure and thus the temperature of the machine.

they are normally adjusted by way of tiny screws on their surface. some electronically minded gadget freaks have replaced their p-stats with electronic devices called p.i.d. controllers.

however, many espresso machine experts -- that is people who actually build and repair them, not just random armchair freaks who play espresso repairmen on the internet and may have never had a girlfriend longer than a week -- have strong arguments that when steaming milk for cappuccini, the standard sirai p-stat is actually a better mechanism than the p.i.d.

the italians will make this case with vehemence, in my experience.

i won't pretend to be a machine expert, no way! but after years of listening to the various factions duke it out, and drinking lots of coffee along the way, i have slowly and tentatively come to the conclusion that the italians are most likely right here.

they don't dazzle you with b.s. but have a nice, fairly clear explanation as to why a standard hx machine with a mechanical p-stat is better for those wishing to make coffee beverages with steamed milk. it's too long to repeat here, so i won't even try.

(listen carefully readers and you will hear the last of the pro baristi hitting the floor as they clutch their chests in shock.)

so there i am, lifting off caesar's warming tray and staring down into the perforated screen covering over his brain box and other assorted electric/electronic parts. this cover boasts a small black cap lettered "sopac."

embossed on this black cap is a plus and minus sign with swoop between them -- to show you the direction to turn the tiny little screw to adjust the temperature. in this case, you are supposed to turn the screw counter-clockwise to reduce the temp.

having done this with carlos expobar, i thought it would be a cakewalk on caesar. but alas, no.

in fact, i believe it's impossible to do this at home. here's why.

ok, so the black cap comes off easily. this leaves you staring into a deep hold about the width and depth of my thumb.

where is the p-stat? where is the little screw on top of the p-stat you are supposed to turn with your finest eyeglass screwdriver?

i couldn't see down into the hole for the life of me. so i got out my big light.

but alas, caesar is so shiny and reflective even inside that it was hard to see! finally by angling the light i discovered the edge of his p-stat.

unlike carlos, whose p-stat is a little yellow plastic thing that looks like a pot of lipgloss, caesar has a professional sirai p-stat. this is a bigger rectangular black plastic box, about the size of the box the average wristwatch comes in.

it has a small hole in the cover in which you delicately insert your flathead screwdriver and turn gently.

that is, if you can reach it. which in caesar i could not, because the p-stat box was offset rather far from the hole in caesar's brain screen.

if i inserted my screwdriver at an angle so i could reach the sirai's case, i actually couldn't see down into the sirai itself to ensure i was actually in contact with the screw.

hmm. ok, so i retreat. i take out caesar's water tank, and i unscrew the 2 phillips head screws that are holding the brain screen on. the brain screen has a lip that fits up inside the steel piece covering caesar's forehead, so you have to pull down on it and a little back.

but the brain screen is quite stiff and also attached at the bottom. in short i don't see how to get to the sirai at all without stripping caesar naked.

taking off all his lovely mirrored panels and then disassembling his insides seems like quite the chore. in fact, i don't quite know how to do it safely.

certainly you'd want to do it with care so you don't scratch any of his gorgeous sides. . .

so i stopped. clearly this is a task that requires more consultation with jim p. than i thought!

i'll email him on monday for a strategy discussion. maybe there's an easier way that i'm missing.

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posted by fortune | 1:18 PM | top | link to this | email this: | links to this post | | 4 comments

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