PID/temperature unstable?

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fantomas

#1: Post by fantomas »

Hi
I have a Profitec Pro 600. When the machine is on, it keeps a pretty stable temperature of 95 degrees celcious (I'm from Europe). But after pulling a shot, the temperature rapidly decreases to 86-88 degrees, and it then takes 1-2 minutes for the temperature to get back up to the set temperarure of 95 degrees. So it is impossible to do back-to-back shots because of the temperature. Is this just how it is with the Profitec 600 or could it be an issue with the machine?

I used to own a Sage/Breville Oracle Touch which didn't seem to have these temperature drops after pulling a shot. They are both dual boilers, but maybe Sage/Breville just don't show these temperature offsets on their display?

Thanks

PIXIllate
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#2: Post by PIXIllate »

This sounds normal for an e61 group. It will have a declining temperature profile and a 90ish second rebound. You'd probably notice less fluctuation at 93C as 95C is definitely at the top of the brewing range even for light roasts.

If you're cleaning, grinding and prepping faster than that you're probably not doing a very good job on your WDT and puck prep which will have a negative effect on your shots.

Additionally, good espresso tastes better as it cools. Slow down and enjoy your coffee.

fantomas (original poster)

#3: Post by fantomas (original poster) »

Thanks a lot! I was just getting nervous that the machine was out of order, as I was expecting the PID to do a better job at holding the temperature whilst brewing the shots.

PIXIllate
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#4: Post by PIXIllate »

That test also does not accurately reflect the water volume of a real shot. The puck provides resistance and absorbs about ~2-2.5x it's weight in water and then you have the shot in the cup. So maybe 70-80g of water total over a longer period of time.

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cafeIKE
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#5: Post by cafeIKE »

fantomas wrote:I have a Profitec Pro 600.
Is this a new machine?
If not, it could be a failing sensor.

PIXIllate wrote:This sounds normal for an e61 group. It will have a declining temperature profile and a 90ish second rebound. You'd probably notice less fluctuation at 93C as 95C is definitely at the top of the brewing range even for light roasts.
Nonsense. I can pull back to back to back shots on my e61 DB or HX. The temperature rises a couple of degrees over a handful of shots.
Dinner Party / Kaffe Klatch MO is to measure out all the doses, grind, prep, brew & steam. Rinse & Repeat.
"This latte is incredible!!!" 8)

Looking at the boiler pic for the 600, it's possible they are injecting water at the boiler top. Dumb idea.



Pull that fitting and if there is no pipe attached, get a welding shop to braise a tube ½ the brew boiler depth.
This will inject water mid boiler. You may need to tweak your PID settings to improve response.
PIXIllate wrote: If you're cleaning, grinding and prepping faster than that you're probably not doing a very good job on your WDT and puck prep which will have a negative effect on your shots.
More nonsense. Not all need WDT.

PIXIllate wrote: Additionally, good espresso tastes better as it cools. Slow down and enjoy your coffee.
Says you. Some coffees deteriorate to dreck when cool, particularly ABUDE's

PIXIllate
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#6: Post by PIXIllate »

Sigh.

Pflunz

#7: Post by Pflunz »

Actually, I am impressed that the temperature is that high. The Pro 600 hast a 750ml coffee boiler. You are extracting solid 400ml in 20 seconds and the temperature only drops from 95°C to 88°C.

As already stated, this is not representable for a normal shot.

Additionally, typically the temperature sensor is near the inlet of the boiler. This will report the highest temperature difference (good for PID controlling) but the water at the outlet will always be hotter.

Bluenoser

#8: Post by Bluenoser »

fantomas wrote:video

Hi
I have a Profitec Pro 600. When the machine is on, it keeps a pretty stable temperature of 95 degrees celcious (I'm from Europe). But after pulling a shot, the temperature rapidly decreases to 86-88 degrees, and it then takes 1-2 minutes for the temperature to get back up to the set temperarure of 95 degrees. So it is impossible to do back-to-back shots because of the temperature. Is this just how it is with the Profitec 600 or could it be an issue with the machine?
In the video, unless you've cut something out.. the reheat time is about 80 seconds.. and you've pulled at least 150-200ml of liquid. A shot will only take about 60ml and does it over 25-40 seconds .. so the effect should be greatly reduced. It seems highly doubtful you could grind, prep and pull in much less than a minute. The Pro600 should be able to keep up with you with 60 seconds between pulls. 750ml is not a bad size.. the LMLM has only 170ml brew boiler. Are you still finding it takes 120 seconds even with a regular coffee shot? (18g in, 36g out in 30s?)

I would say one poster might be a bit critical.. I certainly need WDT in my VST baskets.. and that's with a $3k grinder.. so some form of WDT is not a bad idea. Not all HXes can pull back to back shots.. My Pro500HX (admittedly a slower machine than most Pro500s) takes 5-10 minutes to get its thermosiphon back up to the exact same temp. He might be right that an inlet at the top might affect it a bit.. but if you are getting reheat in a minute, I can't imagine welding a pipe on to improve that unless you are making a party-load of shots.

And maybe you could pull fine when the PID reads 93.. One thing in all these E61 machines is that the PID reads somewhere in the boiler and you don't have an exact idea of the brew water unless you use a SCACE.. It might be that if you pulled shot #2 at 93 it might taste indistinguishable from shot #1.. something to try.

there was another thread from a poster who complained bitterly his Pro600 was slow when pulling Americanos.. but when we queried how he was getting the water for the Americanos, he didn't reply.. so not sure if he was pulling them from his brew boiler and seeing something like you are describing.. But if you are only 1 minute for recovery for a shot (not an Americano).. that seems pretty good. But interesting you are the 2nd to complain about slow rebound for the Pro600 in recent posts.

fantomas (original poster)

#9: Post by fantomas (original poster) »

Again, thanks for all the replies. Some great input and thoughts. I guess it will be more accurate to see how it performs pulling an actual shot. So I might just do a video of that and post here as well.

The machine is brand new - which is also why I am a bit concerned that the PID didn't do a better job keeping the temperature up, because it doesn't sound like the pump starts. But I guess it does, since the temperature comes down quite a lot. I just didn't feel this was an issue at all with my old Breville/Sage Oracle Touch.

Pflunz

#10: Post by Pflunz »

Just a small calculation:
The Pro 600 has a 1200W (maybe 1400W, I am not sure which is for which) heating element for the brew boiler.
With ~4kJ/K/kg heat capacity, in 20 seconds you can heat 300ml water by Delta T = 20s*1,2kJ/s / (4kJ/K/kg * 0,3kg)= 20K.
This results in 40°C warm water you add to the boiler (as simplification, I know I let out some things). As I said, I am impressed by the temperature stability.

A back calculation, to heat 300ml to 95°C, you have to heat for 75K/20K = 3,5 --> T = 20s*3,5 = 70 seconds with full power.