erics wrote:That is very unusual for the group temp to vary that much. Normally, the group temp varies in a cycle similar to the boiler pressure/temperature cycle but greatly attenuated.
Is your portafilter in or out of the group and what is your room temp?
The range is because of after 60min heatup and lower for second shot after five minutes.
pre restrictor i was 205-206 after 60 min heatup.
post restrictor i am at 198-199 after 60 min heatup.
Bluenoser wrote:On a Profitec Pro 500 PID (HX), using Erics Thermometer, I have set the PID to get an idle of about 199 after 60 minute warm up. No flush and it will rise to 207 about 10 seconds into extraction and settle back to about 202. Portafilter is in with the warm up. After one shot, my idle decreases to about 195. But that next pull will go up to 202 and finish about 198.. (less of a swing). I've got to be careful at this point, because after the 2nd shot, my idle will be down to about 190. I need to wait a bit to get up to 195 to pull that 3rd shot or it will be sour. This takes about 5 minutes, maybe more.. still learning.. on mine.
I'm assuming the big E61 will even out the temps as the brew water exits.. so that first shot likely runs a bit hot.. and later ones are pretty close to 200F. I find that I have to leave the portafilter in as much as possible or it will cool off group too much.
Very interesting because i had the pro 500pid's restrictor and it is 2.25mm, but the tube (upper e61) is wider that comes from hx tube. So the machine is engineered slightly differently but i have gotten very good results adding a 2.6mm restrictor to my non pid machine (2.25 did not work as well).
One thing i am finding, and i will have to confirm is that if the bump is higher the shot does change the flavour so thats why i do a flush to reduce the hump. My hump is around 203.5-204.5F after a 4-5second flush. I wait five minutes or more for my second and follow up shots and i get consistent results (only a quick 1-2 seconds screen flush).
Try to do a screen flush starting at 5 seconds and reduce it to 4 and 3.. and see how the flavour of the coffee changes, if it doesnt then without flush is good for you but for me i am finding the hump does change the flavour a bit for my coffee.