Bezzera Unica brew pressure adjustment

#1: Post by **adimatteo** » November 22nd, 2015, 4:10 pm

Does anyone know how to change the OPV on the bezzera unica. It is currently set to 12 bar and I would like to reduce it to around 9. With the pressure being so high, I have to grind the beans extra fine to get a decent espresso, which essentially leaves fine grinds in my espresso. I've read a few things here and there on adjustment, but nothing on how to specifically do it. Any guidance would be appreciated.

Thank you.

#2: Post by **tocateclas** » December 24th, 2015, 7:54 pm

Hi adimatteo,

I have an Unica and have the very same problem. Despite changing stock baskets for IMS, I have always had fines in my cup. As I have tried everything grinding and tamping, I am wondering if it's pressure related. But I know two Unica owners which are brewing at 12 bar and are not having this issue...

I'm probably trying to do it next week. Look this thread in the forum: Bezzera Unica problem

Let me know if you have solved the fines issue!

#3: Post by **tocateclas** » December 25th, 2015, 3:12 am

adimatteo wrote:I have to grind the beans extra fine to get a decent espresso, which essentially leaves fine grinds in my espresso.

Not fines with the Silvia using the same grinder?

#4: Post by **tocateclas** » December 26th, 2015, 6:07 am

adimatteo wrote:Does anyone know how to change the OPV on the bezzera unica. It is currently set to 12 bar and I would like to reduce it to around 9. With the pressure being so high, I have to grind the beans extra fine to get a decent espresso, which essentially leaves fine grinds in my espresso. I've read a few things here and there on adjustment, but nothing on how to specifically do it. Any guidance would be appreciated.

Thank you.

I set it at 10 bar yesterday. It's easy. Just remove the case (four screws at the bottom), remove one wire of the boiler, put the blind filter and switch the pump on. Unscrew the opv to lower the pressure, screw to increase pressure. In the thread Bezzera Unica problem you can see the bolt you have to move.

I have not noticed any improvment fines related lowering opv. But I have made just a couple of shots.

#5: Post by **tocateclas** » December 26th, 2015, 6:17 am

adimatteo wrote:Does anyone know how to change the OPV on the bezzera unica. It is currently set to 12 bar and I would like to reduce it to around 9. With the pressure being so high, I have to grind the beans extra fine to get a decent espresso, which essentially leaves fine grinds in my espresso. I've read a few things here and there on adjustment, but nothing on how to specifically do it. Any guidance would be appreciated.

Thank you.

Could I know when did you buy your machine? Removing the drip tray you will see the manufacturing date. Mine was made in 2014.

http://users.rcn.com/erics/ · #6: Post by **erics** » December 26th, 2015, 9:53 am

Bezzera has a "9 bar" kit designed for several of their machines. It has part number 5900524.01 and is carried in the US by 1st-Line.

http://www.1st-line.com/store/pc/Bezzer ... 2p6649.htm

From looking at the Unica parts catalog from Bezzera, it APPEARS that this kit would work. Send me an email (below my sig) and I will send you the installation instructions.

#7: Post by **tocateclas** » December 28th, 2015, 11:07 am

Thanks erics,

I think there is no need to buy this kit. I just opened the Unica and unscrewed the opv and set it at 10 bar. Didn't try to lower it till 9 bar. Anyway, still fines! So it must be grinder related. No leaks outside the portafilter, no dirtyness in the group, no grounds contamination on the spouts. Group gasket is new. Filter, shower and portafilter have been cleaned with pulycaff. I have checked everything carefully...

#8: Post by **tocateclas** » December 28th, 2015, 11:10 am

erics wrote:Bezzera has a "9 bar" kit designed for several of their machines. It has part number 5900524.01 and is carried in the US by 1st-Line.

http://www.1st-line.com/store/pc/Bezzer ... 2p6649.htm

From looking at the Unica parts catalog from Bezzera, it APPEARS that this kit would work. Send me an email (below my sig) and I will send you the installation instructions.

I have just read your link. This kit is designed for machines manufactured before november 2013. Mine is from 2014 so no noises or problems lowering the opv till 9 bar. I haven't made any espresso at 9, will try later. But I am afraid pressure is not related to my "fines problem".

http://users.rcn.com/erics/ · #9: Post by **erics** » December 28th, 2015, 5:00 pm

I certainly cannot disagree with anything you all have said but let me add some more info.

At one point in time Bezzera published an "accessories" catalog (I'll call it edition 1) and the last page of that catalog illustrated a 9.0 bar kit designed for models BZ07 PM, BZ09, BZ10, SELENIA, GALATEA DOMUS, and GIULIA. This kit included TWO adaptors for the valve body. You would use only one depending upon the particular espresso machine model.

Their latest accessories catalog (I'll call it edition 2) does not contain any 9.0 bar kit from what I remember.

The Bezzera 9.0 bar kit from 1st-Line includes THREE adaptors for the valve body. I just ASSUME that three adaptors would then make this latest kit applicable to all of their models. The OPV included in all kits is a standard OPV but NOT like any installed on Bezzera machines I have seen. It is fully adjustable to whatever pressure you desire.

#10: Post by **tocateclas** » December 29th, 2015, 2:22 am

Great info, thanks. I supose with new Bezzeras (from 2014 onwards) you can set the pressure you desire. I have just set it to 9 bar with no issues for the moment. The OPV bolt of my Unica is not like the 1st-line kit, but I don't know how is it internally as I haven't dismounted it.

At 9 bar I have less fines but still more than I should, so this must be a grinder problem. It seems easier to get a more stable flow, overall with the one cup filter basket.