cajun_brew wrote:Received my thermometer adaptor kit and installed with no problem.

For people using this for flush N go technique how are you getting your target temp? I assume you have to flush past your target temp and try to predict how much the temp is going to "bounce" back to the target temp at the GH. This may take some practice as I watched mine bounce back from 5-10 F depending on if the machine has been idle or pulling back to back shots.

Duhhhhhhh...... I guess I should have played around with thermometer kit more than one day before posting this.

After doing a short series of flush 'N wait I can easily get GH and HX to the same temp and have found that a 30 sec or so pause and I get a steady temp reading for duration to the shot. Count me in as one who thinks this is a fantastic mod for any HX. Even if you have mastered the water dance (I have not) it's worth it to never have to look or listen to the pre shot flush.

cajun_brew wrote:After doing a short series of flush 'N wait I can easily get GH and HX to the same temp and have found that a 30 sec or so pause and I get a steady temp reading for duration to the shot. Count me in as one who thinks this is a fantastic mod for any HX. Even if you have mastered the water dance (I have not) it's worth it to never have to look or listen to the pre shot flush.

I haven't seen this description before but I think we have a new mode: flush n' wait or maybe flush 'n pause. We can add this to the flush n' go and flush n' rebound modes.

I experimented today with lowering my boiler 2 degrees and the flush and wait seemed to work even better. I was between .9 and 1.0 bar on the pressure gauge with my PID reading of 248. I was able to hit 203, 202, 201 and 200 and maintain a steady intra-shot temp of +-1degree. I suspect this was pretty good given that my measuring devices are not calibrated in tenths and are home grown. I was pausing 30 seconds from the end of the flush to the start of the shot. The above temps were achieved with readings on the adaptor when ending the flush of 207, 206, 205,204. The temp would fall about four degrees during the wait period.

Thank you Eric!

DougS wrote:I haven't seen this description before but I think we have a new mode: flush n' wait or maybe flush 'n pause. We can add this to the flush n' go and flush n' rebound modes.

Flush-n-wait/pause seems to be same method just another name as flush-n-rebound. While waiting/pausing the machine is rebounding! Don't see a need for another name for the same method. Then again, 2 or 3 or even more names for the same thing could be good for confusion in discussions.

Compass Coffee wrote:Flush-n-wait/pause seems to be same method just another name as flush-n-rebound.

I think Doug refers to a post from the Bench:

HB wrote:After a few tries, I wondered if the Vibiemme would produce a flatter brew temperature profile using Eric's "flush and wait" approach. This alternative to flush and go / flush and rebound hasn't been talked about much in the forums, but in a nutshell, it's a slow reverse surf. I flushed down to ~198 and then watched the grouphead thermometer slowly rise to the target temperature:

«missing video»

I overshot the target temperature, but the overall profile is much flatter. It's a slow technique and only practical if you have Eric's adapter, still it may be worth updating the HX Love article to describe these three techniques (flush and go, flush and rebound, flush and wait).

Which refers back to Eric's original post:

erics wrote:All of these temperature measuring devices behave in the same manner (for a vibe pump E61 machine) as illustrated in the chart below which shows temperatures during the FLUSHING RITUAL ONLY.



This chart is really important as it vividly and accurately illustrates how the E61 grouphead temperatures are varying during the flushing process and in the time period after the flush is stopped. For sure it would be interesting to create the same type of chart for an E61 machine equipped with a rotary pump because the flowrates during the flush are vastly different.

"Flush and wait" is flushing well past the target temperature; the thermosyphon movement stops and then slowly re-establishes itself over the course of a few minutes. Using the grouphead thermocouple / thermometer adapter, you monitor the temperature rise and start the extraction when the desire brew temperature is reached (or use a timer for a previously determined brew temperature / flush / wait).

Unfortunately, (or fortunately if you're CoffeeKids), this flush-n-wait method really depends on having a temperature monitor.



The idea is to start flushing and start preparing the basket at ABOUT the same time and pull the shot at a particular grouphead temperature. It is well suited to the user (like me) who prepares 1 or 2 drinks at a time.

The three interesting things to note from the chart (some, pretty obvious) are:

a. the relationship between idle grouphead temperature and pstat settings
b. higher grouphead temperatures require a few more seconds of flushing to reach the same temp
c. the rate of temperature decline during the flush (for a given machine) is dependent only on flowrate

"c." is unique to a vibe pump machine - I hope to have some numbers for a rotary within a month.

OR - if there is an E-61 rotary nut in the Washington DC area . . .

As usual, this MS Excel file is available for the asking - erics@erols.com

Eric,

I guess we should agree that to control the shot temperature we must understand the dynamics of the flush and recovery behavior of the specific machine in question. My point, not clearly stated, is that the smaller boiler prosumer machines have a distinguishable behavior pattern from the larger boiler commercial machines brought into the home even though the commercial machine may be a single group HX.

In my particular LSM if you draw down a flush beyond the end of the water dance say to 196 degrees, it doesn't rebound very quickly. On the other hand, the intra shot stability was very poor when I flushed down to an acceptable point to flush 'n go. Pausing 20-30 seconds at this point, say 206 degrees, had a big impact on the intra-shot temp. If I had a thermocouple in the HX inside the boiler I think I could show that the point of recovery was in that portion of the system.

Also I can tell that all of this is sensitive to the temperature of the incoming water line. Summer is here, my home water temp is rising, and it is affecting the rebound rate of the HX. My machine is located in the garage where heat is an issue.

For sure, watching the temp on the adaptor in the Group Head is a huge advantage. Measuring the temp of the water going to the PF is the best single thing that I have done. Plus it is a huge amount of fun.

DougS wrote:I guess we should agree that to control the shot temperature we must understand the dynamics of the flush and recovery behavior of the specific machine in question. My point, not clearly stated, is that the smaller boiler prosumer machines have a distinguishable behavior pattern from the larger boiler commercial machines brought into the home even though the commercial machine may be a single group HX.

I do agree that controlling the shot temperature and/or shot temperature profile is important but, even more so, is the importance (really benefits) of ensuring CONSISTENCY from shot to shot.

And yes, I would be interested in seeing what a commercial E-61-ish hx machine does as regards temperature behavior under similar conditions (flush to 185 F).

As another happy user I just want to say another thanks to Eric for donating all his profits to CoffeeKids! They are a great charity and those of us spending so much money on these expensive toys need to remember the luxury we enjoy. It's clear Eric is doing this for the good of the community because if I had to source all these little parts it would have been a nightmare.

I have the built in thermometer version and have a couple of points:

- Easy to install. Pull bolt out, stick adapter in. Don't overtighten.
- It looks pretty good with this little black thermometer barely sticking out of the grouphead. Definitely meets spousal approval.
- The cheapo digital thermometer is surprisingly responsive. You will learn the behaviour of YOUR machine, not a posted chart. For example I was consistently underflushing after the water dance with my Anita.
- Most importantly it has raised my espresso pulling consistency 100%. For me with an Anita set at 1.0 bar I just flush to 190 deg., do my grinding tamping thing, and pull at 198. Not having to think too much for your early morning first espresso is a relaxing change.

If your're on the fence on this one I'd recommend doing ordering one right away. The absolutely worst outcome would be that you end up putting the original bolt back in and CoffeeKids has a little extra money. That's not so bad is it?

- BobT