# How accurate are the PID on brewtus 4?



## David_Sweden (Oct 16, 2013)

My pid still have the default factory setting. Should I change anything? Can I check that the temperature is correct against what pid shows on the display?

I'm thinking if I can use a regular oven-thermometer to check the temperature on the water from the grouphead? What temperature should I aim for?


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## xiuxiuejar (Jan 24, 2012)

One of the wonderful things about the Brewtus is that you can regulate the brew temperature. As for the 'right' temp, that's personal. I found that with Jampit, I had to aim for 93 or 94 degrees whereas with the Ethipia I'm drinking at the moment, 95 is better for my taste. Remember that there is a 10 degree offset on the Brewtus. Play around - you can always restore the factory settings!


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## Xpenno (Nov 12, 2012)

I think that Garydyke calibrated his and found it to be 4 deg lower at the group than it read on the PID. I'm sure he'll chime in to confirm though.

Cheers

Spence


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## jeebsy (May 5, 2013)

The offset might need adjusted to get the display matching the brew temp.


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## garydyke1 (Mar 9, 2011)

Yeah my machine was running cooler than the PID had indicated. The flashing to steam at 99/100 thing doesn't seem to be particularly accurate


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## kikapu (Nov 18, 2012)

garydyke1 said:


> Yeah my machine was running cooler than the PID had indicated. The flashing to steam at 99/100 thing doesn't seem to be particularly accurate


So are you now brewing slightly hotter now? I seem to recall (not stalking honest!) before you did the testing with the sage you said your brew temp you were using was in general around 91/92 which was in reality even lower!!?? Obviously the taste is the most important thing rather than the actually temp just curious if after the testing you went back to much lower temp or you found the higher temp actually improved the shot for you?

I originally set my offset to 11 but I guess based on your findings I might need to change it to 8 or 9.


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## David_Sweden (Oct 16, 2013)

Sorry. Double post....


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## David_Sweden (Oct 16, 2013)

garydyke1 said:


> Yeah my machine was running cooler than the PID had indicated. The flashing to steam at 99/100 thing doesn't seem to be particularly accurate


How did you do to get the exact temperature?

I'm thinking if I can pump out water from the grouphead in a cup and measure with a kitchen-oven thermometer. Does that sound like an ok idea?


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## garydyke1 (Mar 9, 2011)

Yes I got to the exact temp using the scace.

I was brewing at 92 and in reality it was 90 ! Now my 92 is 92. I also adjusted the pressure to match the sage (so a truer side by side test) the result was better shots


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## jeebsy (May 5, 2013)

What did you adjust the pressure to?


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## garydyke1 (Mar 9, 2011)

10 BAR going by the onboard gauge when using a blank basket, resulted in 9-9.25 BAR when using the scace


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## kikapu (Nov 18, 2012)

One think I found last night with the steam boiler off the PID display did dance about a fair amount upto 4deg C above set point! I know this doesn't mean that the actual boiler temp is doing that but I have noticed in the past the temp displayed does seem to flux that much more when the steam boiler is off!

I think I am going to change my temp offset to 9 currently at 11 as was when I set it up that meant it just stopped flashing off at 99 but based on Gary's findings its likely 2degC change will be about right!! Also the BB guide recommends the 9degC offset from their test was better to use than the standard default of 10! (And the one shot I tried at 96 with some Rave beans last night certainly wasn't overly bitter.


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## garydyke1 (Mar 9, 2011)

Having both boilers on should be more temperature stable - more thermal mass?


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## jeebsy (May 5, 2013)

The pressure on mine is running a bit low just now, maybe because there's no pressure from the line whereas cc had 2bar of line pressure.


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## garydyke1 (Mar 9, 2011)

Mines a vibe pump, I couldn't comment on rotary, expect it to be around 9.5 on gauge = 9BAR with scace


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## David_Sweden (Oct 16, 2013)

Thanks for all help!

My PID showed about 2.5 degrees Celsius low. Now I have 95 degrees on PID-screen and 95.5 - 95.6 degrees Celsius with my fluke multimeter on the output at the portafilter .


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## David_Sweden (Oct 16, 2013)

garydyke1 said:


> 10 BAR going by the onboard gauge when using a blank basket, resulted in 9-9.25 BAR when using the scace


Ok, so it's shows 0,5 bar higher on the onboard

gauge than the real pressure.

You mean that you can recommend me to set the pressure to 10,0bar then using blind filter?


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## garydyke1 (Mar 9, 2011)

I couldnt say 100% without a scace TBH. Change it and see how you get on, its easy enough to change back again : )


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## David_Sweden (Oct 16, 2013)

garydyke1 said:


> I couldnt say 100% without a scace TBH. Change it and see how you get on, its easy enough to change back again : )


I have lowered the pressure from 10.5 to 10.0 bar now. I had to do a small adjustment on thé grinder but now I make some really good espresso shot. I don't know if I notice any difference in taste, but psychologically it feels better to know that the machine is correctly adjusted 

Thank you once again for your advice and help!


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## dsc (Jun 7, 2013)

David_Sweden said:


> Ok, so it's shows 0,5 bar higher on the onboard
> 
> gauge than the real pressure.
> 
> You mean that you can recommend me to set the pressure to 10,0bar then using blind filter?


You will always see less pressure when not using a blank basket as there's some flow going through the Scace device (ie. less resistance, less pressure). You shouldn't really be using a blank basket to set pressures, it's quite easy to simulate a coffee bed just by using paper towels in a normal basket. Stick enough in (be cautious, they get hot and water can squirt around if you are not careful) to slow the flow to get your normal espresso flow rates ie. 30ml in 25s, then use that 'coffee bed' to set the pressure.

Regards,

T.


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## Bob Henderson (May 17, 2013)

I found the PIS to be a great thing to have on my Exobar as I wanted a lower temperature for my afternoon coffee, using something more floral like Ethiopian, I would bring it right down to 92 degrees


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## David_Sweden (Oct 16, 2013)

dsc said:


> You will always see less pressure when not using a blank basket as there's some flow going through the Scace device (ie. less resistance, less pressure). You shouldn't really be using a blank basket to set pressures, it's quite easy to simulate a coffee bed just by using paper towels in a normal basket. Stick enough in (be cautious, they get hot and water can squirt around if you are not careful) to slow the flow to get your normal espresso flow rates ie. 30ml in 25s, then use that 'coffee bed' to set the pressure.
> 
> Regards,
> 
> T.


You probably have a point about the pressure via a scace. But I think it is a good approach to adjust the pressure with the blind filter to get a reference value.

Regards David.


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## gman147 (Jul 7, 2012)

Flash to steam at 99c is a good manual way of getting your expo close to ideal operating temperature. It''s not perfect because of the elements that surround the water are of course thermal conductors. You're always going to be a little out +/-.


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## garydyke1 (Mar 9, 2011)

Nothing beats a SCACE and Fluke for calibration, my machine was running way off


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## David_Sweden (Oct 16, 2013)

garydyke1 said:


> Nothing beats a SCACE and Fluke for calibration, my machine was running way off


I used a fluke and putted the sensor in the hole at the outputs under the portafilter wile I flushed out a lot of water.


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## gman147 (Jul 7, 2012)

Any idea where I can borrow one?


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## jeebsy (May 5, 2013)

poona said:


> Any idea where I can borrow one?


That is the million dollar question....i'd love one to check my PID offset is right


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## Charliej (Feb 25, 2012)

jeebsy said:


> That is the million dollar question....i'd love one to check my PID offset is right


Maybe Glenn has one?


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## jeebsy (May 5, 2013)

i thought Sage had the only one in the UK?


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## GS11 (Feb 20, 2013)

jeebsy said:


> i thought Sage had the only one in the UK?


Is it possible to get a reasonably accurate result with a fluke and thermocouple i.e. without the scace?


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## mym (Sep 15, 2009)

Charliej said:


> Maybe Glenn has one?


Alas, Glenn confirmed to me that he doesn't have one. He said he usually rents one from CoffeeHit when required.

If any Londoners want to share rental costs we could get a few done in a day maybe... I'll mail them and ask what the cost is.


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## Charliej (Feb 25, 2012)

jeebsy said:


> i thought Sage had the only one in the UK?


No Sage had the only naked PF for the Sage DB packaged with the Scace they lent to Gary. I would imagine there are quite a lot more than one of them in the UK.


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## jeebsy (May 5, 2013)

mym said:


> Alas, Glenn confirmed to me that he doesn't have one. He said he usually rents one from CoffeeHit when required.
> 
> If any Londoners want to share rental costs we could get a few done in a day maybe... I'll mail them and ask what the cost is.


Yup. I'd be interested


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## mym (Sep 15, 2009)

mym said:


> I'll mail them and ask what the cost is.


Alas, again : "Unfortunately we no longer offer that service."

Have now bought a Hygiplas Multistem Thermometer and will have a go with that and a partially blocked portafilter.


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## kikapu (Nov 18, 2012)

Maybe the forum could purchase one then loan it around the members!?? By purchase I mean if enough member's were willing to donate to fund it although the funds maybe better used for something else (members day etc) just a thought as would be very useful and interesting to a growing number of us

Obviously if this did happen for such a high value item I would sugguest you might need more than three posts!!?? And that would have it first!


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## GS11 (Feb 20, 2013)

It's disappointing that these machines leave the factory without being adjusted. Perhaps it's a service the retailer ie BB could provide when benchmarking the unit.


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## dsc (Jun 7, 2013)

I'm currently working on a quick mod to a standard basket which would allow for a TC (3mm sheathed) to be mounted through the basket and held in place. All you need then is to fill the basket with paper towels to slow down the flow and you can measure away. If I get one done it will be up for grabs (ie. borrow), as long as you have something to connect the TC to.

Regards,

T.


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## GS11 (Feb 20, 2013)

dsc said:


> I'm currently working on a quick mod to a standard basket which would allow for a TC (3mm sheathed) to be mounted through the basket and held in place. All you need then is to fill the basket with paper towels to slow down the flow and you can measure away. If I get one done it will be up for grabs (ie. borrow), as long as you have something to connect the TC to.
> 
> Regards,
> 
> T.


Good news... Would be interested if this becomes available albeit would need to source a meter. Any idea what would be considered minimum requirement for a meter?


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## dsc (Jun 7, 2013)

You'd need something which can accept a thermocouple input for type K thermocouples, this in itself should provide at least 0.1degC display resolution, as for precision I'm guessing the more you pay the better it gets. This would probably work well:

http://www.ebay.co.uk/itm/Therma-3-Digital-Thermometer-K-Thermocouple-and-1-metre-Air-Wire-Probe-/281260908496?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item417c74dfd0

it's useful to have one anyway and keep with a bare wire TC for general temp checks in coffee.

Regards,

T.


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## Obnic (Jan 14, 2014)

I'd be interested in collaborating / contributing to get some form of accurate PF temperature and pressure measurement facility for the forum that could be loaned out. Glenn, is it worth taking this further.


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## poolfan (May 9, 2014)

jeebsy said:


> The offset might need adjusted to get the display matching the brew temp.


So the PID controller allows you to adjust the temp display for a given input signal from temp probe i.e.calibrate the temp loop yeah?

What reference temp did you use - water into a cup with an accurate temp sensor in it?


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## twistywizard (Sep 3, 2012)

Raising an old thread. Did this go anywhere?


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## unoll (Jan 22, 2014)

Thread revival again! I knocked up my own portfilter temperature gauge using a pressurised basket with bonded in K type thermocouple, I used it a few times with the Gaggia to get an idea of what was going on but now I've got a Brewtus to play with and offset tweak. With the Brewtus during a 30 second pull, the temperature being read started at maybe 5°C-10°C below the target temperature then by maybe 22-25 seconds was at target followed by maybe 0.5°C above target for a couple more seconds.

My understanding would be that the temperature starts low and climbs whilst the water is filling up the basket and the portafilter is heat sinking and then eventually gets to temperature and sholdn't go higher.

The question is this, should my temperature reading be the peak temperature I read on the meter on maybe a longer time or should I maybe be taking an average. Can anyone who has done similar testing with better equipment (such as a scace), give advice on how to interpret the temperature readout and how long to measure for?

By the way, as an added detail the thermocouple is a decent quality one I've borrowed from work which has been professionally calibrated so I'm pretty confident in the readings I'm getting.


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## jeebsy (May 5, 2013)

The group cools down if the machine is sitting idle. A wee warming flush before pulling your shot helps reverse this, as does leaving the pf in the group beforehand


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## Obnic (Jan 14, 2014)

I'm jealous of your calibrated thermocouple. Tried building a clone SCACE myself and concluded that I could not trust the thermocouple.

I had a Brewtus and it was both accurate and stable. This was established on the bench at Bella Barista at several temperatures over several pulls.

I would say that you are seeking to establish the temperature of the water delivered at the group head not the average puck temperature during the course of a shot.

Design of your temperature measuring basket and what you pack it with, and how water flows through it, is therefore important. There's a cracking thread on here started by Xpenno I think about building your own basket to mirror puck flow without introducing big heat sinks. Davecuk has also done some solid work on this problem. Boots has also played around lots with a SCACE thermocouple so can advise methodology.

As for me, I would say, once you have a temperature neutral'ish apparatus then preheat the machine with the portafilter in the group, flush the group for four or five seconds, wait ten seconds and pull the shot.

I would not expect big swings in temperature unless you run the shot for a very long time.

The Brewtus PID and group design is, in my experience, very stable and capable of proper accuracy.

H


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## DoubleShot (Apr 23, 2014)

jeebsy

What do you have your PID set to, 94 degrees c?


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## jeebsy (May 5, 2013)

94 yeah, think my offset is 10 but I'd love a scace to check it


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## DoubleShot (Apr 23, 2014)

Mines set to 94 on PID plus I have an Erics thermometer fitted (keep forgetting to switch it on but that's another issue altogether, lol!). I have found some of the coffees I've made a tad on the cool side and if not drank straight away they are not hot enough for a couple of family members I've made them for.


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## jeebsy (May 5, 2013)

DoubleShot said:


> f not drank straight away they are not hot enough for a couple of family members I've made them for.


Re-education required


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## DoubleShot (Apr 23, 2014)

Yeah that's what I keep trying to tell them...this is not instant coffee made with 100 degrees c boiling water from a kettle!


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