jeffg wrote:it seems that my machine might not have a thermosyphon installed. How dire are the implications of this? I have contacted the roaster where I bought the machine for their thoughts on the matter including some references listed here..

You're a victim of metricitis. This is a common syndrome among espresso hobbyists who believe that everything that can be measured should be measured and then should be worried about ... a lot.

Put your meters in the closet for a week (at least) and adjust your machine and your flush by taste.

jeffg wrote:After leaving the machine on for 1hr my thermometer reads 213 is that a problem?

Marshall wrote:You're a victim of metricitis.

Marshall, I was thinking exactly the same thing until Jeff posted his Vibiemme's idle temperature. That's outside the norm for the models Dave and I evaluated, but consistent with other HXs that don't have thermosyphon restrictors. Most E61 / HX espresso machines don't have restrictors, so it's certainly isn't a "serious" condition. However, if the restrictor is indeed absent, it means the information presented in the Buyer's Guide and specific advice offered by other Vibiemme owners won't apply.

Below is a photo of flow restrictors for the Vibiemme Domobar Super, courtesy of Ian (cafeIKE):

cafeIKE wrote:The restrictor (61 / 62) is in the TS / boiler connector. No need to remove the group from the machine.

My boiler is currently set to an uncalibrated 231.5 / 0.65bar and the group idles at a calibrated 200.
From The Bench

yikes, well i doubt i will be able to have a restrictor in for a week or so, any advice on how to manage my temp until then? I am stoked that my problems are likely related to not having this part. i've been having to flush like mad to get the head temp down which in turn then screws up my other temps and complicates things for me anyways)

You might be able to COME CLOSE by initiating the "flush to" ritual when the grouphead attains 200-201 during the machine warm-up phase - possibly around 25-30 minutes after you first turn on a "cold" machine.

You might also improve matters by reducing your boiler pressure (pstat setting) such that the maximum gage reading is, say, 0.70 bar. But I hesitate a little on this one because I don't know what pstat you have (the review machine had a Parker pstat) and 0.70 bar MAY BE outside of the adjustment range. See Vibiemme review - page 3. Keep in mind that it takes some time for grouphead temperatures to stabilize at a new level - you're dealing with 9 lbs +/- of brass.

jeffg wrote:yikes, well i doubt i will be able to have a restrictor in for a week or so, any advice on how to manage my temp until then?

Assuming the restrictor is absent, follow the instructions in HX Love. That is, flush until the "water dance" ends + a few seconds, allow a short rebound, pull. Fine tune by following Marshall's advice: Put your meters in the closet for a week (at least) and adjust your machine and your flush by taste.

(It's a guess, but I would start out with flush to end of dance + four seconds, 20 second rebound, pull. Precede the first shot of the day with a "warm up" flush, i.e., flush as if preparing for an extraction... wait 3 minutes... then do the normal flush routine).

currently in talks with the main distributer. He is stating that the US models are different and the NZ/AUS models have been calibrated to idle at 194F on a setting of 1.5 So..... I have sent him a pic of my machine at 1.1 idling at 213F, will see what they say and post back..

Jeff, I recently bought one of the thermometer adapters and played with it for a couple of days to see how it works. I think its easy to get suckered into thinking your machine cannot hold a reasonably constant brew temperature because the numbers seem unstable. You really have to be aware of what you are actually measuring with the device. The brew temperature is a result of the group head and HX water meeting and averaging together in the coffee puck. When water is not flowing you are basically measuring the grouphead temperature. When water is flowing, you are mostly measuring the water temperature coming from the HX, which flucuates a lot depending on how much flushing you do.

What I have learned from playing with the device is how consistent the temperature readings are of the group head at idle, of the water coming from the HX at various flush volumes and of the group head temperatures after various flush volumes (after stabilizing). For example, when my machine is idle for a half an hour or more, the grouphead (with pf) temperature is always 211 degrees. The flowing water temperature at 6 oz of flush volume is always about 195 degrees and the group head temperature (after stopping the flush and allowing a few seconds for the temperature to roughly stabilize) is always 204-205 deg. After 30 seconds of idle time, the group head temperature always settles to about 200 degrees and stays within about 1 degree of 200 during 2 oz of additional flushing (an approximate shot volume).

I think the device has helped me a lot in understanding how the group head and HX water temperature change with the flushing volume and rebound time. Based on what I am seeing (for me, seeing is believing), it appears that flushing by volume is actually a very accurate way to reproduce a specific grouphead and water temperature and could certainly be used as the only method of controlling brew temperature. I think the device makes reproducing temperatures easier than measuring volumes and times (and especially so for making small changes) because it allows you to concentrate on measuring only one factor instead of two. I think it's a definite benefit but probably not a "gotta have".

At the moment, I have been playing with the different flush/rebound modes that have been discussed in this forum to see which one best matches my speed in getting the puck ready. I'm new to making espresso so the longer deep flush and wait that Eric suggests in the instructions has been my main mode of operation but I am getting faster at grinding/weighing/tamping, etc. so the flush to 195 and rebound to 200 is close to taking over as the normal mode.

In the end, you still have to use taste as the final judge of what temperature or volume to flush to and what temperature or time to rebound to. The device gives you some reference points to work with to make changes to until you find the combination of flush and rebound that matches the speed you work at and that gives you the best tasting result.

Thanks everyone for your input, I am starting to understand temps a bit more now. drminpa when you say "flush to 195 and rebound to 200" I am assuming you flush until your thermometer reads 195, then you wait until the thermometer shows your group head at 200? Thanks again!

Not so unreasonable questions for the Australian distributor would be:

Where do you measure and how do you measure?
What size thermosyphon restrictor is installed in AUS/NZ Vibiemme machines or is some other methodology utilized?

Certainly, not knowing the details, that temperature (194 F) with that boiler pressure (1.50 bar) seems unreasonable.

You can always direct him to my FTP site which details the hows and whys of the digital thermometer, including the "calibration" procedure.

http://users.rcn.com/erics/

jeffg wrote:when you say "flush to 195 and rebound to 200" I am assuming you flush until your thermometer reads 195, then you wait until the thermometer shows your group head at 200? Thanks again!

Yes, stop flush at 195 F (equals 6 ounces water flush for my Vetrano) then wait until the thermometer reads 200 degrees - corresponds to almost exactly 30 seconds of wait time) then pull shot (grind/fill/tamp pf in between stopping flush and starting pull).