# Bezzera Unica 11 bar



## 8144 (Oct 9, 2014)

Hi folks!

Recently bought a Bezzera Unica PID and whilst I am enjoying the shots it produces I have noticed that it tends to sit at about 11 bar of pressure when pulling a shot.

I'm not doing anything 'strange' in terms of what I'm trying to do: usual dose is 20g in and 40g out in about 28-30secs but the pressure is at 11 bar.

Is this normal? I've been lead to believe that 9bar is more like the right kind of pressure for espresso. Would there be a noticeable difference between a shot pulled at 9bar as compared to one pulled at 11?

I have seen on older posts on other forums that Unica owners have adjusted the OPV down so that the pressure decreases so I am just wondering if this is something that is going to help. Unfortunately I cannot seem to find a video or a decent set of instructions so if anyone has any links that would be great.

Down the rabbit hole I go!!


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## MediumRoastSteam (Jul 7, 2015)

condy01 said:


> Hi folks!
> 
> Recently bought a Bezzera Unica PID and whilst I am enjoying the shots it produces I have noticed that it tends to sit at about 11 bar of pressure when pulling a shot.
> 
> ...


 You can always adjust the pressure to something that you want. Usually 10 bar is the norm for those machines.


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## 8144 (Oct 9, 2014)

MediumRoastSteam said:


> You can always adjust the pressure to something that you want. Usually 10 bar is the norm for those machines.


 Thank you. Any idea how I go about doing this? I have a rough idea but I'm not willing to fiddle about with the inner section of the machine without really knowing what I'm doing.


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## John Yossarian (Feb 2, 2016)

As a first step you might need to find exploded diagrams for your machine. These might be available on the Bezzera website. If you go to some sites that sell spare parts they also might have those.


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## MediumRoastSteam (Jul 7, 2015)

@condy01 - Sorry I do not. Basically, in general terms, the expansion valve has a spring, and the tension is controlled by turning a nut. You need to identify that component on your machine and just do that.

Apart from that, I don't know the specifics about your machine, really sorry.

Needless to say, if you don't know what you are doing, I wouldn't do it. And, unless you think your coffee is bad... I'd leave it alone. 🙂


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## BlackCatCoffee (Apr 11, 2017)

Take the case off. You will find a brass valve with a nut on the end with a plastic tube coming off it. Pop a blind basket in, switch it on to brew and twist the nut whilst keeping an eye on the gauge.

Set it to about 9.5 bar to be 9 at group.

This is NOT your machine but this is what the valve looks like -

Oh and btw Bezzera set it at the factory to what they say is correct. They do not recommend you change it although many people do.


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## MediumRoastSteam (Jul 7, 2015)

@condy01 - Precisely what @BlackCatCoffee says. I wanted to find the video for you but was busy with other things.

This is a video from Bezzera themselves explaining all the rationale behind 11bar.


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## 8144 (Oct 9, 2014)

BlackCatCoffee said:


> Take the case off. You will find a brass valve with a nut on the end with a plastic tube coming off it. Pop a blind basket in, switch it on to brew and twist the nut whilst keeping an eye on the gauge.
> 
> Set it to about 9.5 bar to be 9 at group.
> 
> ...


 Thank you ????

This kind of begs the question, if Bezzera have set it to be 'correct'... is 11 bar when brewing actually correct or is 9 bar correct? I guess what I would like to know is if pulling a shot at 9bar will make a noticeable difference to end result?


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## BlackCatCoffee (Apr 11, 2017)

condy01 said:


> Thank you 🙂
> 
> This kind of begs the question, if Bezzera have set it to be 'correct'... is 11 bar when brewing actually correct or is 9 bar correct? I guess what I would like to know is if pulling a shot at 9bar will make a noticeable difference to end result?


 That is a whole can of worms. What I would say though is that Bezzera machines go through extensive bench testing before they leave the factory and will (hopefully) have been tested again by the retailer that sold it to you. If they thought 9 bar was best it would have been set at that.


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## 8144 (Oct 9, 2014)

BlackCatCoffee said:


> That is a whole can of worms. What I would say though is that Bezzera machines go through extensive bench testing before they leave the factory and will (hopefully) have been tested again by the retailer that sold it to you. If they thought 9 bar was best it would have been set at that.


 True. I'd rather not go down that rabbit hole in fairness. I think I'll leave it for now but thank you for the advice 🙂


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## ajohn (Sep 23, 2017)

The rational on using different pressures with Ulka type pumps as against pro rotatry ones is that they build pressure in a totally different way and flow rates as the video mentions.

It's a try if you want and you can always go back to 11. I have a Sage DB which comes set to 10. A refurb that some one has changed to 9. One day I will put it back to where it should be. One effect will be a finer grind for the same ratio. Who knows best, the makers who have worked on the machine or web comments in this area. The 9 bar is from yonks ago. It could be a number that was picked out of empty air and may have suited some particular machine.


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## Baffo (Jan 23, 2021)

condy01 said:


> Thank you 🙂
> 
> This kind of begs the question, if Bezzera have set it to be 'correct'... is 11 bar when brewing actually correct or is 9 bar correct? I guess what I would like to know is if pulling a shot at 9bar will make a noticeable difference to end result?


 "is 11 bar when brewing actually correct or is 9 bar correct?" >>> You're trying to answer a question which likely has no right answer. Higher/lower pressure can be more or less useful depending on the context.

"I guess what I would like to know is if pulling a shot at 9bar will make a noticeable difference to end result?" >>> Unless you're afraid, tightening/loosening a valve nut can give you the answer to that. However, what works with your current beans might not work with other beans and vice versa, so you will get ONE answer, not THE answer. As others have said, if you like the coffee you're making and you are within certain generally accepted parameters, I wouldn't worry much.


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## 8144 (Oct 9, 2014)

Baffo said:


> "is 11 bar when brewing actually correct or is 9 bar correct?" >>> You're trying to answer a question which likely has no right answer. Higher/lower pressure can be more or less useful depending on the context.
> 
> "I guess what I would like to know is if pulling a shot at 9bar will make a noticeable difference to end result?" >>> Unless you're afraid, tightening/loosening a valve nut can give you the answer to that. However, what works with your current beans might not work with other beans and vice versa, so you will get ONE answer, not THE answer. As others have said, if you like the coffee you're making and you are within certain generally accepted parameters, I wouldn't worry much.


 Yeah in fairness it's probably not something I'd really notice.


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