Profitec 500 PID temperature experiences

Need help with equipment usage or want to share your latest discovery?
sirajgb

Postby sirajgb » Aug 17, 2018, 7:43 am

Hello,

First post after much much reading on this website.

I just received my profitec 500 PID, upgraded from a gaggia classic after many years.

I am trying to figure out optimal temps setting for the PID. I found that the manual recommends staying between 119 to 121 C (246-249 F) which corresponds to a brew temp of 92 -94 C.

I pulled my first shot at 121 using the grind that worked for the classic (medium roast coffee), it was a great step up from what I was having before. Then I started experiment and went to the 94 setting and my shot wasn't as good, a little watery. I proceeded to make the grind finner but I am surprised that a 1 degree change (0.5 C at the brew temp) can have such an effect. I got amazing shots but can't replicate the best one I pulled, which was the first shot I pulled...I have a stepless Eureka grinder so I forgot where the dial was.

Are there any users out there that want to share experiences here?

shanewiebeftr

Postby shanewiebeftr » replying to sirajgb » Oct 22, 2018, 2:21 pm

I'm usually between 252 and 254 with a small flush if the machine has been sitting idle for a long time. With temps at 250, I never ever had hissing water and at 254, it only hisses after sitting for over an hour and for less than a second. I typically go for lighter roasted beans and have been pulling consistently good shots imo

LK

Postby LK » Oct 22, 2018, 6:45 pm

I have been using medium roast coffee and have had my best results have been at 251* or 252* on the pid, which is a bit hotter than where you are. At those temps, I have tried cooling flush, but I have never seen a steam flash, so I don't bother any more. Are you able to weigh your coffee and shot to see if that is constant?

Bluenoser
Supporter ♡

Postby Bluenoser » Feb 01, 2019, 11:24 am

I've had mine for about 7 months..

I have Eric's thermometer.. I found with my PID I had to go high.. 256F.. no flash steam.. group idles at 199-201.

After 45 min warmup with no flush, my pull peaks quickly at 207 and then settles at 203 for entire 30 second shot. I am assuming puck is seeing about 200 (3F drop). I don't have SCACE to confirm.

My rebound is slow, though.. if I do a 250ml latte, I need up to 10 minutes to fully rebound. Not really happy with that. I can do a 2nd shot after a few minutes and brew water is still about 200 (I think), but after that I'll need 15-20 minute wait.

On my machine, seems the restrictor is making rebound slow. Not sure all machines are experiencing this.. but mine is.

bach

Postby bach » Feb 01, 2019, 2:14 pm

I think the difference in shot quality you've seen probably doesn't stem from the temperature change but grind/distribution/extraction difference. Unless you dramatically change the temperature I wouldn't expect a completely different extraction, but rather a subtle change in flavour profile.

Do you weigh your shots? If not, that'd be a great place to ensure consistency before playing around with temp.

Bluenoser
Supporter ♡

Postby Bluenoser » Feb 10, 2019, 2:04 pm

Some more info..

Did some tests.. 4 shots (no steaming or flushing) 5 min. apart. PID=255. Eric's thermometer installed.

All shots had temp reading of 199-202 for last 1/2 of the shot. At the beginning of shot #4, the thermometer was reading 192 and previously I was waiting for that to rebound to about 197, which was taking 10 minutes or more. Doesn't look like I need to. Although shot #4 started at 192, 1/2 way through the group water was showing 199 and steady.

If I do a cleaning flush, or some steaming, the recovery may be a bit longer.

Now my machine has been on for hours, so everything is really warm.

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Jake_G
Team HB

Postby Jake_G » Feb 12, 2019, 11:56 am

Dave,

I couldn't held but take notice of this post where you commented:
Bluenoser wrote:On a vibe pump (assume rotary too, but only have vibe), you can put the lever to the neutral position for the last 4 grams.. Some say that helps the flavour.. Similar reasoning as above. I do it as a regular part of my shots, but haven't done an A/B comparison yet.

Are you following up your shots with a screen clearing flush? Letting the shot flow sans-pump at the tail end of the shot could lead to boiling in the HX with the loss of pressure and a minor TS stall, which could impact your rebound time and idle temperature. In general, there is more than enough capacity for heat transfer between the boiler and the HX to rebound quite quickly, it's the heat flow through the thermosyphon that dictates the rebound temperature of the group, and your ability to pull back to back shots. Anything that impedes this flow from the design point will cause frustration (assuming the design point is a good one! :P).

I've mentioned it before, but flushing before shots is not always about cooling the brew water. Often times it is employed to heat the bell of the group and can be used quite successfully to shorten rebound time and improve consistency, but it all depends on what happens when you first lift the levetta. If the temperature falls, there's not much hope. I suspect you will find that it actually increases a few degrees before falling off again. The transfer of heat between the boiler and HX is very efficient. After just a few minutes, any water added to the HX should push very hot water into the group, raising its temperature. Only trial and error will tell you how high you can and should raise the temperature between subsequent shots, but the fundamental principles of how these machines work suggests that such a technique would be helpful rather than hurtful given your current experiences with a flush-less workflow.

Cheers!

-Jake

Bluenoser
Supporter ♡

Postby Bluenoser » Feb 12, 2019, 1:50 pm

Jake_G wrote:Dave,

I couldn't held but take notice of this post where you commented:
Are you following up your shots with a screen clearing flush? Letting the shot flow sans-pump at the tail end of the shot could lead to boiling in the HX with the loss of pressure and a minor TS stall, which could impact your rebound time and idle temperature. In general, there is more than enough capacity for heat transfer between the boiler and the HX to rebound quite quickly, it's the heat flow through the thermosyphon that dictates the rebound temperature of the group, and your ability to pull back to back shots. Anything that impedes this flow from the design point will cause frustration (assuming the design point is a good one! :P).

-Jake


hmm.. I know so little about this stuff.. I was watching a video from somewhere..not sure so won't guess the source.. but what I presume was a knowledgeable barista was using a stock machine, like a Pro 500/Rocket HX, maybe a DB.. not sure, but they simply put the lever into 'idle' for the last 3-5 seconds. Their explanation was to reduce the flow profile at the end of the shot.. and I'm guessing to simulate what a lever might do..

I had no idea that letting a shot flow without the pump could lead to the issue above.. I am not doing a screen cleaning flush as I was having rebound issues and so thought more cleaning would reduce the TS hot water. So you are saying this "post shot idle" is a 'bad practice' , which is great info.

in a general flushless workflow, you'd recommend a short cleaning flush? Now I've heard a 1 second or less can introduce air into the TS.. do you think this is an issue? I was also worried cleaning flushes might deplete the TS of hot water and slow my rebound.. In one of the few times my temp was 202, I did a 3 second flush to reduce the temp to about 198 and shot was great and I did notice a fast recovery.

With Eric Therm. I do notice my temp increases quite a bit when the shot starts and then falls and levels off at what I am assuming is the true brew water temp the puck will see. I've been finding that even when Eric indicates a low idle temp (192), if everything is sufficiently heated, a shot pulled will rise up to 200 and stay there. I had been waiting until the idle temp returned to about 198 (which took about 10 minutes and hence my bitterness about performance), but that doesn't seem to be necessary. Still lots for me to learn about the thermal properties of my Pro500PID HX.. Can't imagine doing it without a group thermometer, but sometimes numbers can be a bad thing when the user doesn't really know what's going on and how to interpret them.. :)

Thanks for taking the time to reply, Jake.

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Jake_G
Team HB

Postby Jake_G » Feb 12, 2019, 2:15 pm

Bluenoser wrote:So you are saying this "post shot idle" is a 'bad practice' , which is great info.

Well,

To clarify, I'm saying that letting the HX depressurize and then sit and stew is a bad practice. As long as you bring it back up to pressure, all is well. This means letting the pump run long enough for your brew pressure gauge to show a normal flush pressure. No more than that should be needed to abate any concerns of a TS stall.

Bluenoser wrote:in a general flushless workflow, you'd recommend a short cleaning flush? Now I've heard a 1 second or less can introduce air into the TS.. do you think this is an issue? I was also worried cleaning flushes might deplete the TS of hot water and slow my rebound.. In one of the few times my temp was 202, I did a 3 second flush to reduce the temp to about 198 and shot was great and I did notice a fast recovery.

As long as the brew gauge registers pressure before you stop the flush you should be ok. However, what happens in practice always trumps theory...

That said, you should see your temp gauge go up with a flush before going down on account of there being superheated (256 degree?) water in your HX. It's not really possible for your group to idle at a hotter temperature than the water that heats it, if that makes sense. The temp starts falling after the cold water injected into the HX mixes and hits the group. The geometry of the injector in the HX, the size of the HX and the size of the TS restrictor all work together to tune the temperature response of lifting the levetta, so it's possible that your machine behaves differently than a cursory evaluation by the likes of me from many miles away may suggest. Do some test flushes and see what happens. Do a 10 second flush after a long warm up. See what happens. Does temp go up and then down? Does it dip and then rebound before falling again? Does it just fall like a rock? Knowing these things will help you make educated guesses that lead to functional workflow changes to increase your shot-to-shot consistency.

Bluenoser wrote:With Eric Therm. I do notice my temp increases quite a bit when the shot starts and then falls and levels off at what I am assuming is the true brew water temp the puck will see. I've been finding that even when Eric indicates a low idle temp (192), if everything is sufficiently heated, a shot pulled will rise up to 200 and stay there.

This hump is an indication that the initial shot temp would increase with a brief flush. Try it and see. In addition to testing what a longer flush, test shorter flushes as well as the rebound will be different for different flush amounts.

Cheers!

-Jake

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Radio.YYZ

Postby Radio.YYZ » Feb 12, 2019, 5:13 pm

Jake,

As far as i have read the HX Hump as measured by eric's thermometer is negligible, when compared to a scace measurement alongside eric's thermometer. See graph below from post by Dan:

Image

brew temperature problem, pre-infusion temperature is way high..

Different machines and different tuning of the system would yield different results but takeaway for me was to understand that eric's thermometer measurements and how it translates to the cake/puck. I ignore the hump but use it as a guide/prediction to what the future temperature during the shot would be. The hump also indicates that it is a flush n go shot, i found for a flush n wait, there was no exaggerated hump. As per that thread i experimented by only looking at temperature 10-15second in and at the end to gauge the actual temperature at the cake/puck.
Good Coffee: Technique/Knowledge > Grinder > Beans > Water > Machine