The theoretical ideal temperature is ~94 degC.
I would be really interested to know just what temperature I should be seeing if I remove the M6 allen head bolt from the front of the E61 and place a thermocouple probe into the hole.
I assume that I should have this a few degress above ideal extraction temp ...!!!
Which is ?
Please those with the wisdom come forth .
The theoretical ideal temperature is ~94 degC.
Ive been wondering about the thermostability of the E-61 HX as well.. How do you regulate the temp of something which can be affected by ambient temp which changes all the time? The theory is that the boiler heats up water into steam and the pressure is regulated by the pressurestat and will cycle on ond off depending on the pressure within the boiler. The water for brewing is flash-heated (thermosyphon?) through the boiler to boiling point the E61 head is engineered such that the loss in the path leading from the boiler to the group head is precisely the ideal brewing temp (am i right to assume this?). However, because the water in the thermosyphon is being heated up to past boiling point, if it is being left idle, the water just gets hotter and hotter, hence the cooling flush. Given factors of ambient temp which will affect the loss of temp, short of something like a PID or an active heating element, how can one claim thermostability of an E61 HX?
I think youre over-complicating and/or over-simplifying. There is more to an HX than a boiler and HX tube passing through it. Ambient temp has little effect on 9kg or so of heated brass, and the claim is verified by devices like the Scace.Originally Posted by 1F3426053E142221233422223E510 link=1244674761/2#2 date=1244684876
After more testing
My machine is Single Boiler VBM, with a 750ml boiler, ....Ok it has been on for 2 hrs and it cycles thru from top of heat cycle (TOC) a number of times .... idling *down, then thermostat kicks in and *back to the top , without pouring a shot.
Using the E61 access hole with a thermocouple placed in the hole and sealed off, the temp never gets anywhere near 91-92 at idle. It is fairly constant 76-78 c.... over an 1 hr. To increase this temp water has to be run thru the group.
The only time I see higher temps is when water is running thru it and that depends on where I have the thermostat set.Currently @ 94.... If I start a 7 sec pour = 60 ml (no resistance) is at 94 c...... *wait 25sec *2nd pour is at 91c ....wait 25sec 3rd pour is 86c wait....& 4th is 83c and thermo cuts in mid pour.
OR *with TOC @ 94c... do 1st pour 2 min after temp has cycled up ....temp is 89c...... Next ...do a 1st pour after 3min after top of cycle (TOC)temp is 88-89c...... Next *repeat again TOC after 4min temp is 88...... After 10min since TOC temp is 82. This suggests that out of any heat cycle you can only get 2 correct *temp pours before it starts to fall away AND *you should only ever do *a single pour after heat has cycled up within the last 3 min.
From this info I have gathered out of the E61 access hole I can draw 2 conclusions of which only 1 may be correct.
1. The boiler of VBM Piccolo is too small , as any influx of 120ml or more of water will throw the temp out ,an extra 2-300 ml would be a great improvement.... OR
2. Single boiler machines with E61 grouphead do not have the the great thermal stability of other E61 machines.It would appear that a SB E61 would greatly *benefit from having a PID *fitted.
Or is my testing technique flawed.....
Any thoughts..... the quest for great espresso continues!
note to Dennis .... I think you mean 9 lb of brass
More like 4-4.5kg Dennis....Nevertheless, youre on the money..;)Originally Posted by 15343F3F3822510 link=1244674761/3#3 date=1244685907
Originally Posted by 71766D6A71767D190 link=1244674761/4#4 date=1244686635Originally Posted by 2B746C7A717A767F7F7C7C747877190 link=1244674761/5#5 date=1244686644
Oops - Im overmetrified! ;D
Check page 9 on this PDF doc Apparently its also related to the pressurestat settingOriginally Posted by 67607B7C67606B0F0 link=1244674761/0#0 date=1244674761
If youre ever down this way, it would be worthwhile having your machine calibrated - OPV and brew temp. A few sponsors have the group handle with pressure gauge and a Scace device. There is also a Scace device that measures pressure as well now but these are quite expensive. Greg Pullman also has a loaner pressure gauge
FOOTNOTE: Chris from TalkCoffee did mine and it made a big difference to the quality of my shots.
yeah thanks Flynn , Im sure running a temp and pressure gauge over the Piccolo might improve things.
But dont get me wrong , I can still extract a great shot out of this baby , but my point is the E-61 group does not live up to its reputation in these small single boiler machines.
Are there any CSers who have installed a PID on one of these or similar ?
*** Or can they accommadate a larger boiler with some lagging to keep it toasty?
***Or perhaps one of our techie guys here can tell me if I can alter or replace the lower boiler temp sensor so it will cut in at 88* or there abouts.
Im open to options....!!!
Currently Im running the boiler a bit hotter 96* (at the group, TOC ) and doing a 20-40 ml flush on first pour , second pour would be in the sweet spot before it drops away, after that I wait for TOC re heat.
You might also want to check this thread: http://coffeesnobs.com.au/YaBB.pl?num=1223588081/0#0