First Time Poster....

I am a relative newbie...got my Andreja about a month ago, and have installed Eric's thermometer. My problem is with my second shot. After finishing the first, and rinsing the screen, the temperature of the grouphead dives into the low to mid 190's and takes about 5-6 minutes to recover to the mid 200's. Is this normal? It seems way too long to me. Do I have a problem with my machine? Any input would be great. Thanks.

Isaac

Next time, don't wait for the brewhead temp to "recover." Pull the next shot as you normally would and watch the temperature during the extraction to see if the indicated brew temperature is "normal." If the brew temp is too low, raise the P-stat's setting JUST A LITTLE BIT. Remember that the temp of the water hitting the coffee is (iirc) about two or three degrees cooler than that as indicated by the thermometer.

Also, be aware that short rinsing (a quick open and close of the brew valve) can cause thermosyphon stall:
try:
Odd Vibiemme Domobar Super thermal behavior
and
Thermosyphon stall on Vibiemme?

I also wrote an article on the subject:
http://home.surewest.net/frcn/Coffee/stall.html

IDK... that sounds about right. I owned the Anita for a while, and the two machines are near identical.
-I ran the Pstat at 1.25ish.. pretty close to what Chris' set mine at when I got it, which was 1.3B, on the nose.

Maybe a TAD low.. but not crazy low. After I would pull the first shot, before enjoying/washing the cup, Id flush the group to scrub the screen/basket, and do the PF wiggle. Then, enjoy the shot/wash the cup. Then, start building the shot, which at that time entailed weighing the beans, doing all the doser brushing/chute purging needed, the WDT, a ridiculous unnecessary amount of useless tamping maneuvers, and then the flush. When I was ready for the seconds shots flush, the group would be about 197F.. maybe a bit lower, but not much higher unless my routine was interrupted. But, when I flushed, the temp would rise up to, IIRC, around 210-212F, idle there for a moment, and then start to fall. Id stop between 208-204, wait 20-40s, then pull.

So, thats why I dont think you're too far off. I very well could be wrong, but what I saw for grouptemps wasn't all that hotter then what you're seeing.

Now, the Quickmill HXs need more recovery time then other E-61 HXs(so Ive read). Two Minutes is roughly the minimum rebound time between shots. Now, you MIGHT be going too fast between shots.. but, I dont think so(but of course, possible). I think you're just going faster then I was, which is almost certainly true, because I purposely took my time between shots, so the machine would overheat, and the water dance was easier to see... FOR ME.

Does this sound like what you're seeing, or am I completely off?

Issac - Welcome to Home-Barista.

Here is a good read on various ways to operate a machine with the thermometer (or thermocouple):
Need hints on using E61 thermocouple adapter
The Quickmill machines are less susceptable to a thermosyphon stall than the Vibiemme but they are, by no means, immune.

A lot could depend on how you prep the machine for that first shot BUT the norm for these prosumer machines is to be able to pull a shot every two minutes. Visit my crude FTP site below my sig for additional info on our machines.

Glad to know that my machine is performing properly.

Jman - I am seeing what you are describing, but if i flush when my gh reads 197, the gh temp drops even lower after the flush.

So whats the importance of the grouphead temperature in relation to brewing temperatures...Is there a number to shoot for? If I perform a cooling flush and a 20-30 sec rebound whats the difference if I pull a shot when the grouphead reads 195, 198 or 204? Or is the temperature of the brewing water more important, irrespective of the grouphead temp?

Next time, don't wait for the brewhead temp to "recover." Pull the next shot as you normally would and watch the temperature during the extraction to see if the indicated brew temperature is "normal."

If the brew temp is normal, but the grouphead is too hot or too cold, wouldn't that have a huge effect on the water temp when it hits the grouphead?

It seems the more I dive into this the more confused I get.

Thanks for all your help.

Hello Issac,
My experience shows me that the temperature of the water applied to the puck is affected by the E61 group temperature.
I have a modified "EricS" thermocouple adapter in my HX machine. It's been modified to carry two thermocouples: one thermocouple at the usual "EricS" position and the second thermocouple located at the shower head dispersion screw just above the puck. The following picture shows the temperature data from a shot at the usual "EricS" in black and the dispersion screw in blue.

As you can see, I let the GH temperature (black) rise to 202F at time~7:50:00 then I ran an HX flush until it dropped back to about 206F at time~7:50:16 with the empty porta-filter attached. Actually to get to 206F, I need to stop the HX flush at about 208F since my temperature display/logger has about 1 second delay in readout. This HX flush step takes the super heated water out of the boiler HX and will reduce the HX hump during the shot. I then remove the porta-filter from the GH, load my pre-dosed and tamped ridge-less basket into the porta-filter and refit to the group. This takes 10 to 15 seconds and I begin the shot at time~7:50:30. During the 10 to 15 second basket loading interval the group temperature (black) is more or less around 206F and dropping. When the shot begins at time~7:50:30, the HX Hump appears and lasts to time~7:50:40. Note this HX Hump period correlates with the pre-infusion time as expected since the flow rate of water through the GH is relatively high as it saturates the puck. When the pre-infusion period completes at time~7:50:40, the water flow rate through the group head drops and consequently the temperature of the group head brings the brew water temperature at the dispersion screw (blue) to about 203.5F (+/-~1/3 F) where it remains for the completion of the shot at time~7:50:55. When I shut off the pump at time~7:50:55 you can see both the black ("EricS" location) and blue (dispersion screw location) temperatures drop quickly as the 3-way valve opens to dump the pressurized water in the saturated puck past the thermocouples to the drip tray. Note the black GH temperature dips to just less than 200F and the blue dispersion screw temperature drops to about 199F which implies the temperature in the basket at the top of the puck was at about 199F at the end of the shot interval when the pump stops and the 3-way valve opens.

Now the tricky thing about HX machines is the GH also acts as a heat exchanger to both cool or warm the brew water as it flows through the group head and since heat transfer in a heat exchanger depends on the flow rate of the water through the heat exchanger this means the temperature at the puck is dependent on the flow rate of water through the GH. Because of this dependency on flow rate, it is very important to consistently grind and dose.

Apologies if this is too much information but it's a complex process.
Andrew

First time poster, so be nice. I just had a eureka moment. I've been researching which machine to buy, and have just settled on the pasquini livia. I have worked as a barista for the past six years so my concerns were repeatability, and temperature stability. My idea is this. For everyday use most of us are not making ten doubles in a row, and steaming milk for each. We'd pull a double here and there, maybe a couple times a day but with plenty of recovery time in between. But what happens when you have a party? Every body wants a latte, and a doppio. No wor ries I've got the solution and it doesn't involve a $500 part 100hrs and masters in electrical engineering. Do what the developers of the Slayer did. Add a pre-boiler. But keep it simple. I have like I would guess many of you here have a hot pot (electric kettle). When company comes keep the reservoir low and when you're ready fill with nice pre heated water. I'm just guessing but temp stability should drastically improve for multiple shots.