GlennT Senior Member Joined: 13 Feb 2012 Posts: 38 Location: SF Bay Area (Silicon Valley) Expertise: I love coffee
Espresso: Kraps Il Primo Steam Wanabe... Grinder: Baratza Priciso Drip: Aeropress & "Don't ask don't...
Posted Mon Apr 9, 2012, 9:41am Subject: Why do espresso machines come with chronically high OPV settings?
I've lost track of how many times I've read threads where the machine has too high of a pressure rating for espresso. In one thread about a commercial machine, I saw something to the effect that Chris' Coffee would be glad to reset the OPV before shipping if asked.
Why should one have to ask?
The only reason I can conceive is that most machines are configured for pod use, which requires higher pressure. For a default to high pressure to make sense:
Pods at normal coffee pressures taste MUCH worse than normal coffee at pod pressure
A higher percentage of espresso machine buyers use pods than it appears on the forums (proportion of coffee geeks who buy is low)
There has to be a logical rationale. I'm just curious about what it is.
Posted Mon Apr 9, 2012, 10:01am Subject: Re: Why do espresso machines come with chronically high OPV settings?
I have read that pod manufacturers (Illy?) specify higher pressures for brewing and many of the "low-end" machines are coming set high (Like Silvias, if the reports are accurate). A lower pressure can be used to brew fresh-ground coffee by adjusting the grind and dose. Unfortunately, the same machines rarely come with a pressure gauge so the user has NO idea at what pressure they are brewing. it has been one of the more common complaints about the price point of the Silvia - sure, it has an adjustable OPV, but no gauge to know what that adjustment would be or what pressure you are brewing at.
"Sorry I was going so fast, Officer. My new Ferrari didn't come with a speedometer."
Stuart Senior Member Joined: 9 Feb 2012 Posts: 113 Location: TX Expertise: I love coffee
Espresso: Breville Dual Boiler Grinder: Baratza Vario Roaster: Air Crazy popper
Posted Mon Apr 9, 2012, 1:09pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
For ESE pod rating, a machine has to produce 11 bar in the extraction chamber. Or so I've read on here. The ESE Consortium's website talks about the advantage of the standard, but doesn't link publicly to the standard itself. The Users Area link regarding the standard is broad-brush stuff: http://www.eseconsortium.com/eng/#par_1
(that doesn't explain the OPV settings on some machines that were not designed to use pods.)
My understanding is the same as yours. I too would assume that non-geeks far outnumber geeks and that explains the higher setting. I, however, can't rationalize this as all machines require a POD conversion kit sold separately. I recognize it is a way to get some extra $ out of the user not purchasing a grinder, but don't understand why this 'conversion' wouldn't include dealer adjustment of OPV to 11 bar, from a properly set OPV on the stock machine.....that, I don't understand.
Posted Mon Apr 9, 2012, 3:36pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
diggi Said:
My understanding is the same as yours. I too would assume that non-geeks far outnumber geeks and that explains the higher setting. I, however, can't rationalize this as all machines require a POD conversion kit sold separately. I recognize it is a way to get some extra $ out of the user not purchasing a grinder, but don't understand why this 'conversion' wouldn't include dealer adjustment of OPV to 11 bar, from a properly set OPV on the stock machine.....that, I don't understand.
I see mention of this on the CoffeeSnobs forum (Australian site) where some dealers adjust machines before sending them out, and Jim at 1st Line mentions having the Le'Lit machines he offers adjusted to 9 bars in the product description. It isn't common practice here in the N. American market but can be found.
Also, it has been discussed how popular ESE pods are in Europe - a manufacturer of home use machines like Gaggia can't afford to ignore the trend by setting their machines up to fail with pods in order work best with ground beans.
I chew coffee beans with my teeth while gargling with 195 F water to enjoy coffee. What is this "coffee brewing" device you speak of?
JDHarding Senior Member Joined: 31 Aug 2007 Posts: 1,099 Location: WA, USA Expertise: I love coffee
Espresso: Ascaso Steel Pro PID Grinder: Nuova Simonelli MDX,... Vac Pot: None Drip: Hario v60 Roaster: Behmor, Fresh Roast
Posted Mon Apr 9, 2012, 4:45pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
I remember my Ascaso Steel Uno Pro was set at around 19 bar pressure, which is why I had a horrible time trying to get my Rocky to grind fine enough, and had to purchase a seperate grinder that would grind fine enough. Thankfully, I bought a pressure gauge and set the OPV down to 9 bar and now even the Rocky can grind fine enough. :)
The Ascaso machines tend to come with a POD basket, although I've never used it myself, but that's probably the main reason the OPV is set so high. 19 bars is a tad too high even for pods, so it really doesn't make any sense.
I had bought and assembled a pressure gauge the night that I confirmed an upgrade from my silvia. So I never adjusted the OPV to the proper setting (didn't want to break anything before I sold it). So I can't answer that, but I was having trouble extracting doses over 18g in the triple from excessive channeling. Think this was in part caused by the high pressure. In theory, I think the grind is relatively fine to combat the increased pressure. So I'm guessing that you'd get many of the changes that go along with grinding too fine.
Indeed I would like to read some answers to this question.
You know those people that want to tell you how to raise your kids but have none of their own? That is how i feel when someone with a kitchen appliance tells me how the merits or dis-merits of my machine or how to use it.
Posted Mon Apr 9, 2012, 7:57pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
I adjusted a friend's Gaggia Classic OPV (reduced) a while back.
I knew with my Silvano that a good shot at 11 bar on the dial hitting the puck was difficult. More often than not the puck showed channeling and blonding - if you stop the shot at this point all is not lost, but volume might not be what you want. If it happens early and you make a run toward the full shot volume you get a bitter tasting over-extracted shot.
His Classic gave shots like the higher bar shots on my Silvano.
I knew what improvement to expect by adjusting his Classic. Since the Silvano by QuickMill has an externally adjustable OPV, fixing the problem (or recreating it) is very easy. The shots hold a tight cone more often than not from beginning till I end the shot. The shot tastes anything but bitter.
I stopped tweaking his Gaggia when the shot pulled like my Silvano when using the same beans and grind. For these two machines at least, lower pressure (8.5 - 9.0) makes the shot better tasting and easier to pull.
I chew coffee beans with my teeth while gargling with 195 F water to enjoy coffee. What is this "coffee brewing" device you speak of?
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