Vibiemme temperature too high during extraction?

[redzone]

I asked Randy G this question and he suggested posting it here.

Thanks in advance !!


Quick VBM question:

I have noticed recently with certain beans that when I pull a shot (double) the temp does not come down
much after the pre infusion stage as it normally does.

The beans are Kenya AA peaberry and also a small blend with the Kenya PB included. The grind is as fine as anything else I use maybe even a tad finer. But the temp stays at 96deg (205deg), through out the extraction and you can definitely taste it in the cup?

Normally after the pre infusion I aim for 195deg ish through out the pull in general and I know some beans are best at difference temps but this one is not as pleasant at 205, and the taste is still off with milk.

Same behaviour from day 3 to day 7.

Other variables are same as usual??

[CafSuperCharged]

Is this coffee and the way it was roasted really intended for espresso?

If yes, try at 190F (88C) and 187F (86C) - 88C +/- 2 being the reference brew temp for Italian style espresso.

Regards
Peter
Netherlands
Europe

[HB]

I have noticed recently with certain beans that when I pull a shot (double) the temp does not come down much after the pre infusion stage as it normally does.

Are you measuring with Eric's thermocouple adapter? More importantly, how does the espresso taste?

If yes, try at 190F (88C) and 187F (86C) - 88C +/- 2 being the reference brew temp for Italian style espresso.

That's the exit temperature of the espresso:

Necessary portion of ground coffee 7 g ± 0,5
Exit temperature of water from the unit 88°C ± 2°C
Temperature of the drink in the cup 67°C ± 3°C
Entry water pressure 9 bar ± 1
Percolation time 25 seconds ± 2,5 seconds
Viscosity at 45°C > 1,5 mPa s
Total fat > 2 mg/ml
Caffeine < 100 mg/cup
Millilitres in the cup (including foam) 25 ml ± 2,5

Assuming redzone is using Eric's thermocouple adapter, redzone refers to the temperature of the water entering the grouphead.

[CafSuperCharged]

That's the exit temperature of the espresso

Dan, I have followed your efforts in this site for years and you are way ahead of me in all these coffee and tech matters, but I am not sure I agree with you here.

In cases where the translation was made by a technical domain expert, or a professional translator with zero technical domain knowledge, I never trust translations 100% so went back to the original language:
Porzione di caffè macinato necessaria 7 g ± 0,5
Temperatura dell'acqua uscita gruppo 88°C ± 2°C
Temperatura bevanda in tazza 67°C ± 3°C
Pressione di immissione dell'acqua 9 bar ± 1
Tempo di percolazione 25 secondi ± 5 secondi
Viscosità a 45°C > 1,5 mPa s
Lipidi totali > 2 mg/ml
Caffeina < 100 mg/tazzina
Millilitri in tazza (compresa la crema) 25 ml ± 2,5

BTW, personally I measure at the exit of the PF - which is how I read your text.
However the question for me still is if "Temperatura dell'acqua uscita gruppo 88°C ± 2°C" actually refers to the exit of the group, i.e. under the shower screen, or the PF. I would expect serious delta t between the two, not to mention upwards in the chain where Eric's sensor would be.

Regards
Peter
Netherlands
Europe

[HB]

However the question for me still is if "Temperatura dell'acqua uscita gruppo 88°C ± 2°C" actually refers to the exit of the group, i.e. under the shower screen, or the PF.

I'll ask a native speaker for his understanding. However, I believe the more important question is still "How does the espresso taste?"

While it's great to have measuring equipment to calibrate, a qualified taster can accurately tell you the brew temperature just as well as most thermocouples, and in less time at less cost. I use measuring equipment for efficiently mapping out an espresso machine's thermal characteristics; for fine tuning, I put the test gear in the drawer and go by taste. Lately I've noticed several threads, like this one, that essentially ask "Why are my measurements wrong?" and neglect to mention the taste defect, if any.

[HB]

BTW, I'm reminded of Andy's point in The goal is great TASTING espresso, not great LOOKING espresso:

Responses like this one from my buddy Dan are driving me a little crazy.

Several years ago, people used to talk about improving the TASTE of their espresso. Developing the ability to taste well was difficult, as was developing the vocabulary to describe what one tasted. But we struggled and learned.

Then the bottomless portafilter came along. Almost overnight, the goal was no longer a great TASTING shot; it was a great LOOKING shot.

Reading the posts here, you'd think that half the people don't drink espresso. They just enjoy watching beautiful bottomless pours flow into the drip tray.

Haven't any of you had a mediocre-looking bottomless pour that tasted better than the perfect-looking pour that came before it? I have.

Is the new goal to produce nice looking charts?

[CafSuperCharged]

I believe the more important question is still "How does the espresso taste?"

You are totally right. I do not measure on a regular basis. Stopped using scales, timer and thermometer. Just an occasional verification of what I am doing so as to be able to communicate on the process with people on the other end of smaller/bigger ponds.

Regards
Peter
Netherlands
Europe

[erics]

An interesting "experiment" to try on the Vibiemme is to pull walk-up shots with absolutely NO FLUSHING prior to the shot. Of course, this assumes you did a short screen flush (2-3 seconds) after the previous shot. I adjusted the pstat (the Parker pstat on the Vibiemme is a pleasure to adjust) such that the max pressure on the machine's gage was 0.80 bar and this resulted in a grouphead temperature of 200 F and a shot temperature of 201 F as measured with a Scace Thermofilter. There was a true 9.0 bar pressure "at the puck" and the shot volume over 25-26 seconds was a very consistent 60 ml.

This procedure would be PERFECT for me as I am the only consumer in the house and my drinks are typically 15-20 minutes apart in the AM.

[HB]

Eric, that's a nice looking chart. How did the espresso taste?

[erics]

To be perfectly honest, at 201F, a touch hot for me and very watery, almost zilch color. However I do understand the temperature problem - its that darn Tabasco influence when I was calibrating the Thermofilter in a bed of Silver Spring, MD steam.

As it turned out, the COMBINATION of the Thermofilter and the meter was reading 0.2F low when compared to the condensing steam temp for my altitude (300 ft.) and then barometric pressure.

[redzone]

I asked Randy G this question and he suggested posting it here.

Thanks in advance !!


Quick VBM question:

I have noticed recently with certain beans that when I pull a shot (double) the temp does not come down
much after the pre infusion stage as it normally does.

The beans are Kenya AA peaberry and also a small blend with the Kenya PB included. The grind is as fine as anything else I use maybe even a tad finer. But the temp stays at 96deg (205deg), through out the extraction and you can definitely taste it in the cup?

Normally after the pre infusion I aim for 195deg ish through out the pull in general and I know some beans are best at difference temps but this one is not as pleasant at 205, and the taste is still off with milk.

Same behaviour from day 3 to day 7.

Other variables are same as usual??

You Guys are way too expert for this green bean !
As mentioned, Yes i can taste it in the cup, and i agree thats all that matters.
The roast was a little light to the eye and certainly to my untrained palate more winey or bright than usual.
I have been roasting SO's to try out the different flavors so as to try a little blending.
The smell of the fresh grind is fruitier (thats what i call it) than others and again I put that down to a to lighter roast.
Yes i normally roast for Ristretto but always sample in milk based drinks too and his was tangy with milk
as well as slightly burnt in the Ristretto.

Sorry for terminology, as it's all pretty new, hence the reason I ask questions, thanks for you help !!

[redzone]

Problem solved ! The pressure stat was set on 1.5 and now I have lowered to 1.1 Erics gauge tells me the temp is down to 93 at worst and no more slightly bitter shots.
Cheers !!!