Pressurised vs Non-Pressurised Baskets

PhilD said:
It's not essential to have a pressure gauge to do the pressure mod. You can instead measure the amount of water dispensed through the OPV return in a given time and refer that to Ulka's pressure/flow graph for the pump model you have to work out its approximate setting.

Easier than I've probably made it sound. I'll let you do the googling but let me know if you can't find the method and I'll see if I can find it.
Click to expand...

It is easier and I did this initially but it was 1-2 bar out when I actually used a meter.
 
Appreciate the helpful tips gents.

Apart from the pressure gauge, what other equipment would I require to do the OPV mod on my Classic?

PhilD said:
It's not essential to have a pressure gauge to do the pressure mod. You can instead measure the amount of water dispensed through the OPV return in a given time and refer that to Ulka's pressure/flow graph for the pump model you have to work out its approximate setting.
Click to expand...
I believe this is the resource you were mentioning PhilD:
http://coffeetime.wikidot.com/opv-over-pressure-valve
 
You need the fittings to connect the gauge to the portafilter (with spout removed), I imagine you should be able to find a little hydraulics shop in Torino.
 
It can be difficult but it will undo...I needed to clamp my filter down, be wary of damaging the chrome by using cloth or tape to protect it.
 
Hedomystico said:
I believe this is the resource you were mentioning PhilD:
http://coffeetime.wikidot.com/opv-over-pressure-valve
Click to expand...

Thanks, Hedo, that's the right graph for most Ulkas, but I couldn't see the method mentioned? Maybe I missed it. Basically though, it's just run the pump into a blank backflush basket so all the water is forced through the OPV, and then work out the flowrate going back through the return tube.

Neill said:
It is easier and I did this initially but it was 1-2 bar out when I actually used a meter.
Click to expand...

Out of interest Neill, was the true pressure higher or lower (assuming the gauge was right..)
 
PhilD said:
Hedomystico said:
I believe this is the resource you were mentioning PhilD:
http://coffeetime.wikidot.com/opv-over-pressure-valve
Click to expand...

Thanks, Hedo, that's the right graph for most Ulkas, but I couldn't see the method mentioned? Maybe I missed it. Basically though, it's just run the pump into a blank backflush basket so all the water is forced through the OPV, and then work out the flowrate going back through the return tube.

Neill said:
It is easier and I did this initially but it was 1-2 bar out when I actually used a meter.
Click to expand...

Out of interest Neill, was the true pressure higher or lower (assuming the gauge was right..)
Click to expand...

The true pressure was higher assuming the gauge was correct.

As for removing the spout, slide a screw driver through the hole from one spout to the the other and use it as a lever to turn the spouts. Also, I held the spouts in boiling water to get them to expand a little and allow me to turn them.
 
Neill said:
As for removing the spout, slide a screw driver through the hole from one spout to the the other and use it as a lever to turn the spouts. Also, I held the spouts in boiling water to get them to expand a little and allow me to turn them.
Click to expand...

Thanks Neill - finally managed to remove the spout using your method.



PhilD said:
Thanks, Hedo, that's the right graph for most Ulkas, but I couldn't see the method mentioned? Maybe I missed it. Basically though, it's just run the pump into a blank backflush basket so all the water is forced through the OPV, and then work out the flowrate going back through the return tube.
Click to expand...

Couldn't find the description of the method through my quick google search, but have decided to use the pressure gauge instead to ensure that the readings are accurate. Acquired the gauge today - just need an adapter to attach it to the portafilter and I should be good to go.
 
Another question for the more knowledgeable espresso enthusiasts.

I am currently using a Hario Mini Slim, which I realise is less-than-ideal in terms of grind consistency but a proper entry level grinder (Iberital MC2 comes to mind) is out of my budget at the moment.

Would you recommend still doing the OPV mod? My hesitation stems from the fact that I'm afraid that the reduced pressure combined with the slightly inconsistent grounds of my Hario Slim may yield worse results than the coffee I'm currently enjoying. The reasoning (guessing?) behind this being that a higher brewing pressure would be more forgiving of grind inconsistencies.
 
Hedomystico said:
Another question for the more knowledgeable espresso enthusiasts.

I am currently using a Hario Mini Slim, which I realise is less-than-ideal in terms of grind consistency but a proper entry level grinder (Iberital MC2 comes to mind) is out of my budget at the moment.

Would you recommend still doing the OPV mod? My hesitation stems from the fact that I'm afraid that the reduced pressure combined with the slightly inconsistent grounds of my Hario Slim may yield worse results than the coffee I'm currently enjoying. The reasoning (guessing?) behind this being that a higher brewing pressure would be more forgiving of grind inconsistencies.
Click to expand...

I don't think there's a disadvantage if you are using a grinder. The reason the pressure was upped was to allow for use of capsules and the pressurised baskets. But, it's not an essential mod and if your worried about it don't do it as its wont make a massive difference.

Oh, and it's worth checking out the graef cm81. It's seems to be quite popular at present for a first grinder.
 
Neill said:
I don't think there's a disadvantage if you are using a grinder. The reason the pressure was upped was to allow for use of capsules and the pressurised baskets. But, it's not an essential mod and if your worried about it don't do it as its wont make a massive difference.

Oh, and it's worth checking out the graef cm81. It's seems to be quite popular at present for a first grinder.
Click to expand...


I might as well try the mod out and see for myself, as I don't use capsules or pressurised baskets anymore (except, perhaps if I were to find myself without freshly roasted beans in the house). I figure I can always revert to the factory pressure settings if I'm not happy with it.

Very competitive price for this Graef grinder! First time I actually hear anything about it. Can't seem to find any thorough reviews for it though :( anyone have experience with it?
 
Thanks Neill and everyone else that has been providing me with helpful coffee-related advice.
I do appreciate your contributions.
I've tried seeking advice on other specialised forums, but the TSR community just appears to be far more friendly and forthcoming.
Guess shaving and being gentlemanly somehow go hand in hand. :)
 
The pressure mod should if anything make the machine more forgiving of uneven grind I think.

Rancilio Silvia got a reputation for being difficult to grind for due to the high pressure setting on the V1 and V2. With high pressure, you have to grind finer to get the same flow through the puck, which is something that cheaper grinders struggle with.

By reducing the pressure and being able to grind coarser overall, you are taking the grinder back towards its comfort zone. Well that's how I'd see it anyway...
 
PhilD said:
The pressure mod should if anything make the machine more forgiving of uneven grind I think.

Rancilio Silvia got a reputation for being difficult to grind for due to the high pressure setting on the V1 and V2. With high pressure, you have to grind finer to get the same flow through the puck, which is something that cheaper grinders struggle with.

By reducing the pressure and being able to grind coarser overall, you are taking the grinder back towards its comfort zone. Well that's how I'd see it anyway...
Click to expand...

Great, all the better then!
Mine was just a wild and uneducated guess based on the fact that pressurised baskets are supposedly more forgiving of inconsistent grinds... so I thought "more pressure must mean better coffee with a sub-optimal grind" :D
 
Let's hope you notice some improvement with the lower pressure. Let us know how it goes...
thumbsup.gif
 
You must log in or register to reply here.
Back
Top Bottom