Olympia Cremina - Maybe the Steam Valve Should Stay Off?

[hperry]

The usually recommended approach to brewing with the Cremina (as I understand it) is to relieve false pressure by opening the steam wand, letting it return to temp, and repeating until there is a steady stream of steam - then brewing. I find when I do that and then draw water through the grouphead to heat it up I am likely to get steam - obviously not good for the coffee. When, on the other hand, I don't open the steam wand and simply draw a shot of pure water first, then draw my shot, I don't get grouphead steam. I also get a great ristretto with a single pull. I haven't seen this referred to so I'm assuming that it's either a failure in my technique or perhaps an issue with this machine.

I'd appreciate feedback from others who are Cremina users.

[espressoperson]

The usually recommended approach to brewing with the Cremina (as I understand it) is to relieve false pressure by opening the steam wand, letting it return to temp, and repeating until there is a steady stream of steam - then brewing. I find when I do that and then draw water through the grouphead to heat it up I am likely to get steam - obviously not good for the coffee. When, on the other hand, I don't open the steam wand and simply draw a shot of pure water first, then draw my shot, I don't get grouphead steam. I also get a great ristretto with a single pull. I haven't seen this referred to so I'm assuming that it's either a failure in my technique or perhaps an issue with this machine.

I'd appreciate feedback from others who are Cremina users.

I don't get your comments about grouphead steam. I see steam when I do a flush, but never see steam when I pull a shot, no matter how hot the grouphead. Are you just imagining the steam will do harm or have you experienced burnt shots? How do your second, third and fourth shots come out compared to your first?

[hperry]

I don't get your comments about grouphead steam. I see steam when I do a flush, but never see steam when I pull a shot, no matter how hot the grouphead. Are you just imagining the steam will do harm or have you experienced burnt shots? How do your second, third and fourth shots come out compared to your first?

If I flush after I've opened the steam valve I get little else but steam from the grouphead. If I flush and don't steam first I get very hot water with a little sputtering. This appears to correspond with the taste - shots 1-3, at least. pulled after a single flush, but not relieving the false pressure by opening the steam valve are rich and full with little bitterness. After opening the steam valve the two shots afterward tend to be bitter and sharp. I attribute that (maybe incorrectly) to the water being too hot.

[bill]

The usually recommended approach to brewing with the Cremina (as I understand it) is to relieve false pressure by opening the steam wand, letting it return to temp, and repeating until there is a steady stream of steam - then brewing. I find when I do that and then draw water through the grouphead to heat it up I am likely to get steam - obviously not good for the coffee. When, on the other hand, I don't open the steam wand and simply draw a shot of pure water first, then draw my shot, I don't get grouphead steam. I also get a great ristretto with a single pull. I haven't seen this referred to so I'm assuming that it's either a failure in my technique or perhaps an issue with this machine.

I'd appreciate feedback from others who are Cremina users.

hperry,
I don't have a Cremina, but I think my Rivera and Elektra work in a similar manner. The system controls the temperature of the water in the boiler indirectly thru a pressurestat. When the machine is first turned on pressure tends to build up in the boiler, actuating the pressurestat, and shutting off the heater before the water has come up to the correct temperature. Releasing the pressure thru the steam value allows the water to come up to correct temp.
Additionally, both of my machines draw water to the grouphead from the bottom of the boiler, making steam thru the grouphead unlikely. I've never seen it happen. The first thing I'd check would be the setting of the pressurestat. I suppose if it was set too high this could cause your problem. Or maybe the small pipe feeding water to the grouphead has come loose?
I'll bet with as many lever users reading this someone out there has experienced the problem, too. I'm looking forward to their responses.

[Dr Jim]

hperry,
I don't have a Cremina, but I think my Rivera and Elektra work in a similar manner. The system controls the temperature of the water in the boiler indirectly thru a pressurestat. When the machine is first turned on pressure tends to build up in the boiler, actuating the pressurestat, and shutting off the heater before the water has come up to the correct temperature. Releasing the pressure thru the steam value allows the water to come up to correct temp.

Hal -

I think that Bill is onto your problem - if your pressurestat is set too high - as in unrealistically high - when you use the 'approved' technique of bleeding off the false pressure through the steam wand you are allowing the boiler to reach full operating temperature which is being held too high by the pressurestat, and you could be seeing steam and spluttering like the HX 'water dance' from your grouphead.

When you do not bleed off the false pressure, you are in essence performing a sort of primitive (and uncontrolled) form of temperature management in which the boiler temperature has stabilized well below where the pressurestat is really set, but is now in the proper range for extracting espresso.

The simple test would be to locate an inexpensive electronic thermometer with a remote probe. Since if my theory is correct there may well be as much as 20 degrees temperature difference between the two states, the thermometer doesn't need to be particularly accurate or even fast-acting. Once you've got the thermometer, open up the case and find a spot to wedge its probe in close contact with the boiler.

Bring the Cremina up from cold, but do not blow off the pressure bubble - note the boiler temperature after 5, 10, and 15 minutes - it should be pretty stable, and run somewhere between 198-210 degrees F. Now, blow off the pressure bubble by using the steam wand and again note the boiler temperature at 5 minute intervals.. My hunch is that the temperature will rapidly rise to well over 212 F, and may stabilize at as much as 220-225 F.

If your pressurestat is set too high, you can use the thermometer to adjust the temperatures by carefully lowering the pressurestat (I think it lowers by turning the screw counterclockwise) by less than a 1/4 turn - steam or flush until the the temperature drops and the element comes on, then note the new temperature after the boiler stabilizes.

It's a fussy, painstaking process, but you should end up with the boiler stable at something like 212-216 which should give 205-208F at the grouphead - which I believe is about right.

The best way would be to tee in an actual pressure gauge - I think Steve R. has a thread on how to do this, it's a fair amount of plumbing, but is very accurate. I also think that Home Espresso Repair may well have a pressure gauge setup for the Cremina and can set the pressurestat for you id you confirm it's set too high.

Cheers

Dr Jim

[bobcraige]

Can you not just use a pressure gauge in place of the boiler cap? This would require no modifications to anything and could be easily used at any time to check the setting.

Bob Craige

LMWDP #47

[hperry]

I appreciate everyone's input a lot

Bill said

"The first thing I'd check would be the setting of the pressurestat. I suppose if it was set too high this could cause your problem.

Makes a lot of sense. And the two follow-up suggestions point to practical ways of doing it.
Dr. Jim suggested that:

The simple test would be to locate an inexpensive electronic thermometer with a remote probe.
The best way would be to tee in an actual pressure gauge - I think Steve R. has a thread on how to do this, it's a fair amount of plumbing, but is very accurate. I also think that Home Espresso Repair may well have a pressure gauge setup for the Cremina and can set the pressurestat for you id you confirm it's set too high.

I've got a Fluke 53 II. Don't have the probe but can pick one up locally on Monday. Sounds like the logical starting point. "Teeing in" is probably beyond my skills. If the temperature turns out to be the problem I can do some rough adjustments to the pressurestat. One thought, on the Bezerra removing the top of the case lowers the temp several degrees C. Would removing the cover skew the results on the Cremina?
bobcraige said

Can you not just use a pressure gauge in place of the boiler cap? This would require no modifications to anything and could be easily used at any time to check the setting.

Interesting idea. Wonder if there is a pressure gauge that would be correctly threaded? Could well be a useful tool for setting the machine up. It appears that this behavior is atypical, so I'll also check with Home Espresso Repair per Jim. Barring a bad pressurestat should be something that needs to only be done once.

Thanks all. What a great resource Home-Barista participants are!

[RCMann]

Interesting idea. Wonder if there is a pressure gauge that would be correctly threaded?

Oly sells a cap with a pressure gauge retrofitted to it. ~$100 plus shipping plus sometimes interminable wait time.

Steve R. put a temporary gauge on his via the steam fitting off the boiler.

I put a permanent one on mine by drilling/tapping the horizontal bar between the head and the pressure relief valve.

There are several ways it can be done, you've just got to use a little imagination. Field expediency is a wonderful thing!

Rod

[hperry]

Thanks Rod for the suggestions. Because I view myself as "technically challenged" for this kind of project, I think I'll pursue the Olympia option depending on availability.

[enigmas12321]

I own a Olympia Crimina and have for 20+ years. I notice that you live in Seattle; I live in Renton.
Should you wish to chat, send an email to me at enigmas12321@yahoo.com, and I'll send you my phone number.
No obligations, I don't know - have never known - anyone else who owns one.

John

[srobinson]

I would not say that attaching a pressure gauge is a difficult feat. There are several places on the machine where they can be attached with the right fittings. I think the key is getting the right match and not damaging any of the threads on the machine. I find the Olympias very stable and I think I will check the pressure on mine with routine maintenance.

With regards to temp or pressure, the factory setting are:

Water Temp: between 190.4F/197.6F
Pressure of the Water in the Boiler: .7ATM to .8 ATM