I seem to be unable to maintain proper brewing temp on my HX machine. I did post this question on another site, but would like to see what answers the expertise of the members here bring.

My machine: Expobar Office Lever (E61) HX.

I just recently purchased an E61 brew group thermometer and started using it to monitor my cooling flushes as well as the temperature displayed throughout the duration of the shot. Here are some of my observations:

*If I take the cooling flush down to an indicated 200F, it takes approximately 30 seconds of flushing.
*When I do this, the temp drops down to 196F after about 5 seconds, and remains at 196 throughout the duration of the shot.
*If I take the cooling flush down to an indicated 205F, it takes about 10 to 15 seconds.
*When I do this, the shot initially starts at an indicated 205F, and within 10 seconds has dropped to and remains at 196 for the duration of the shot.

I thought I read somewhere about the importance of temperature stability throughout the shot -- obviously, I've got nothing close to temperature stability, nor am I able to produce a shot that has been brewed entirely within a 198-202 spectrum.

What am I doing wrong?
Is there anything wrong with my machine?

Thanks in advance for your input.

Is this a new machine? What is your maximum boiler pressure during pstat operation? What does the thermometer read when the machine is at idle after a 45-60 minute warmup?

The reason I ask about whether it is a new machine is that I believe WLL (Whole Latte Love) is installing thermosyphon restrictors in the Expobars they sell.

See this for more "hints" - Need hints on using E61 thermocouple adapter . In addition, the install manual has all of my contact information.

I recently had the same problem. Initially, I was told

Either the brew valve has an intermittent leak or the OPV (thermal OPV in your case) has a leak. Either one is "duck soup" to fix.

by erics and go to Checking an E61 Espresso Machine for Scale to replace the valves. That worked for 2 days, Chris Coffee told me to turn up the pressure stat, which worked for 2 days. The machine needed descaling in the HX.

Marvin

erics wrote:Is this a new machine?

No. It's a used 2008 model that I purchased from a private individual in November of last year. When I brought it home, I descaled it using descaling solution using the following means:

1) I ensured the boiler was full by opening the steam wand and forcing the pump to run (by unplugging the water level sensor) until the solution began coming out of the steam want. I shut off the steam wand, stopped the pump, and let that sit for 30 minutes.
2) Once 1 was done, I raised the brew lever and ran it until descaling solution began to come out of the grouphead; I then stopped it and let it sit for 30 minutes.
3) I then flushed the entire system with fresh water using the aforementioned steps, and ran the brew cycle with the water level sensor connected until the pump re-activated, ensuring the HX boiler wasn't over-filled.

erics wrote:What is your maximum boiler pressure during pstat operation?

I think it's 1.2 bar. The reason I say think is that when the machine if off, the lowest the pressure gauge will read is 0.2 bar (I've opened the steam knob & lifted the cam lever to ensure there's no residual pressure, and there isn't). So I don't know if I'm actually at 1.2 bar, or if I'm at 1.0 bar. Thoughts?

erics wrote:What does the thermometer read when the machine is at idle after a 45-60 minute warmup?

I haven't really noted this as a data point, but feel confident in saying it's around 205F.

erics wrote:The reason I ask about whether it is a new machine is that I believe WLL (Whole Latte Love) is installing thermosyphon restrictors in the Expobars they sell.

The previous owner stated the thermosyphon restrictor was installed; he also mentioned he purchased it new from WLL.

erics wrote:See this for more "hints" - Need hints on using E61 thermocouple adapter . In addition, the install manual has all of my contact information.

Thanks for posting that. It looks like I'm using the flush-to-your-desired-brew-temp method, but without waiting an appropriate amount of time to allow the HX to recover (i.e. as soon as the temp reads 205F, I stop the machine and immediately insert the PF to brew my shot). I'll try some of the other methods and see what I come up with.

Thank you VERY much for your help and input.

iginfect wrote:I recently had the same problem. Initially, I was told by erics and go to Checking an E61 Espresso Machine for Scale to replace the valves. That worked for 2 days, Chris Coffee told me to turn up the pressure stat, which worked for 2 days. The machine needed descaling in the HX.

Marvin

Marvin,

Thank you for posting that link. I definitely haven't taken apart the brew group like that because I don't know what I'm doing. That said, I'm a former Volvo mechanic, and espresso machines are rather simple machines in comparison, so I'm not scared to work on it. That link showed me what I needed to know to feel confident in taking the brew group apart. I'll probably try doing that at some point in the near future to see what it looks like inside. Thanks!

Thoughts?

If the machine is cold and you open the steam valve (you really don't need to open it) and the boiler pressure reads 0.20 bar, yes . . . I suppose it would be a reasonable assumption to say your true boiler pressure is 1.00 bar when heated. Gage mechanisms can have a constant offset and one that varies with the reading. It is complicated and beyond the scope of my typing ability. If we ever meet, I will gladly explain in person . . . from one who has calibrated many pressure gages not necessarily on espresso machines.

You definitely do not need to lift the brew lever. As you were a Volvo mechanic, working on these machines will be a "walk in the park" as long as you have some metlish wrenches laying around.

I've left my machine on and checked the grouphead temp at idle several times and it seems to consistently stay at 205F. I understand the concept of variable offset vs. constant offset -- I agree with you that it's highly likely that my indicated boiler pressure is higher than actual. That said, is ~1.0 bar (the heating element turns off at an indicated 1.2 bar [~1.0 bar actual] . . . the pressure continues to rise about 0.5 bar then stops . . . the heating element cuts on at ~0.9 bar indicated) a good setting, or should I raise it a bit?

I also pulled a shot using the "2oz flush & cooling back flush" method down to 205F. The shot temp initially went up to 206, then stayed at 205 for the duration of the shot -- obviously an improvement on temp stability, but clearly too hot! I drank it anyways just to try it, and it tasted sharper and more bitter.

"Metrish" -- that's funny. The vintage Volvos were all English, then sometime in the 80's they swapped over to Metric, so I've got plenty of both. I'm in the USAF now, but I kept all my mechanic's tools, so while I may get myself into espresso machine trouble, at least I'll be using the right tools

I also have an Expobar Office Lever. The following is the flush routine that works very well for me (all temps shown are from Eric's thermometer). Note my machine idles around 201 (I installed the thermosyphon restrictor). However, these instructions should work pretty much the same if even if you don't have the restrictor, but it may take you longer to do the initial flush.

1. I flush about 5 oz. When I do that, the water temp rises to about 208, stays there a while, then falls. I stop the flush when I hit 200.
2. I then grind and fill the basket. This takes me about 75 seconds.
3. I then pull the shot. My best shots occur when the temp first spikes to 203.5 - 204.5, then quickly settles to 200 - 201 for the duration of the shot. Like most HXes, you'll see this "humped" temperature profile, but after the initial hump the temp is very stable for me.
4. If I'm pulling subsequent shots I usually don't do anything special (i.e. no flushing) and the temp ends up being good.

I think you are much more likely to get better results if you use the "flush and wait" technique as opposed to the "flush and go" technique with the Expobar.

. . . the pressure continues to rise about 0.5 bar then stops

Hopefully, you mean 0.05 bar - that would be normal.

I think you are much more likely to get better results if you use the "flush and wait" technique as opposed to the "flush and go" technique with the Expobar.

I have never operated an Expobar Lever so take these comments with that under consideration. To do a rather lengthy flush and very long wait (due to the thermosyphon restrictor) is probably NOT the best practice from a time standpoint. It is also not the practice employed by most owners of hx machines from the postings I have seen on this site. Note also that I define a flush-n-go as just that, flush and immediately pull the shot.

HOWEVER, if you are making multiple shots in a row, e.g., splitting double shots into two cups for straight espresso or "baby" cappuccinos, this method would produce drinks with a greater temperature consistency.

These two methods are described in the install manual for the thermometer.