# Has anyone tried adjusting the pressure regulator / OPV on a Barista Express or similar



## Dodds25 (Dec 19, 2019)

I'm not clear why Sage designed these machines to run at a higher pressure than most - it must have been a deliberate thing but I'm not sure what the benefit was supposed to be.

Anyway, a few days ago the tank on my BE happened to run dry in the middle of a shot and I lost pressure. I had some bottled water handy so refilled the tank right away - the pressure ramped back up and the shot continued to extract. The result was a much slower extraction for about the same yield. The shot was surprisingly good, so now I'm thinking about reducing the pump pressure by fiddling with the OPV. This was suggested to me a while back but I didn't follow it up at the time.

Has anyone done this kind of mod? I think the gubbinry is designed to be adjustable up to a point, but I've no idea how much.


----------



## TomHughes (Dec 16, 2019)

Dodds25 said:


> I'm not clear why Sage designed these machines to run at a higher pressure than most - it must have been a deliberate thing but I'm not sure what the benefit was supposed to be.
> 
> Anyway, a few days ago the tank on my BE happened to run dry in the middle of a shot and I lost pressure. I had some bottled water handy so refilled the tank right away - the pressure ramped back up and the shot continued to extract. The result was a much slower extraction for about the same yield. The shot was surprisingly good, so now I'm thinking about reducing the pump pressure by fiddling with the OPV. This was suggested to me a while back but I didn't follow it up at the time.
> 
> Has anyone done this kind of mod? I think the gubbinry is designed to be adjustable up to a point, but I've no idea how much.


 @joey24dirt did this on a DTP I believe?


----------



## ajohn (Sep 23, 2017)

It looks like the DTP is the same as the Barista Express. I asked Joey what he read of a gauge on the DTP but no reply other than earlier on that there wasn't really any scope for setting it higher. I do know why he might want to do that, more later.

The OPV on the BE opens at circa 15 bar. It's a little past the blue sector on the gauge. The manuals seem to have lost contact with the designer. The blue sector is the optimum range and personally I didn't have much luck tuning where Sage manuals suggest the needle should go. In some cases that would result in no pressure being generated during infusion so to achieve some the pressure has to go higher. It relates to the bean that is being used. Lower than they suggest might even be better in some cases not that I found any.

I had a problem with my BE grinder that people shouldn't worry about but did talk to Sage about it. It wouldn't adjust finer below a setting that it once did and I mentioned that I often brewed with the needle right up the scale. They said it usually trickles out then, Using it up their does take rather careful adjustment that might even involve very small grinds dose changes. This probably why the suggest staying out of this area. It's tricky.

There is another reason as well on the BE and surprisingly on the DB as well. Both have flow meters. These are located before the OPV valve and wont work accurately when the flow gets too high. It will if the OPV opens too much. The flow meters would cost a* lot* more if they had to take brew pressure so they fit them on the outlet from the water tank even before the pump. They design on the basis that when brewing the opv on both machines wont open at all so that they can be accurate when brewing volumetrically. That can be turned off on the DB where the OPV should be set at 10bar. Many reduce it to 8 even though pundits say vibratory pumps should be set at 9. Rotary 8. The pressure build characteristics are different anyway. It's much easier to get preinfusion with vibratory pump and some machines have pressure profiling. Using 15bar is a little like all of this. None of them will prevent people from making good coffee. If some one changes machine and wants the same taste as they had before they are likely to need to change something. They might get a better drink but if they had changed something on the earlier machine it might even have produced the same drink.

The DB dumps opv water directly into the water tank. The DTP and BE dump it into the drip tray. Too much that way will fill it up rather quickly. On the BE it will mess up it's programmable shot feature. I used that a lot once I found out how to use the machine.

All 15bar brewing mainly means is that less coffee can be used. It's not something to worry about. Taste can still be changed in the usual way. I'd suspect many dtp users are brewing at 15bar with lots going into the drip tray. It's the direction to go for stronger coffee as finer grinds can be used.

John

-


----------



## Dodds25 (Dec 19, 2019)

Yes that makes sense as long as you can grind fine enough and adjust the grind precisely enough, but that's just where the built-in grinder falls down. I will try readjusting the internal ring, which is currently on 4.


----------



## ajohn (Sep 23, 2017)

It doesn't fall down at all. You need to check that the grinder has been set up correctly when it was made.

https://www.coffeeforums.co.uk/topic/49058-how-to-check-any-sage-grinder/?do=embed

You have flexibility on the pressure you brew at, the time the shot takes and the amount that comes out. Those on there own are enough to take care of having a grinder with steps. The other one is small variations in the quantity of beans used. That's the tricky one. My favourite way to use the machine was to use the razor while tuning for a bean as I was using the hopper and timer and each time the grinder is adjusted the quantity that comes out changes so the timer was set to give a little too high a dose. Then comes the problem of finally adjusting the timer. It takes really small adjustments. The other problem is that the weight out wont remain constant for ever. In my experience if the same bean is always used several tiny adjustments will be needed in the first week and then the need tails off but is still needed now and again. If the grinder is cleaned out it can take much longer to settle down. Some people just accept the variation and adjust shot time to suite. A volumetric machine tends to do that anyway.

This is why a lot of people weigh beans in including me. There is no need to do anything to these grinders to use them this way. Just empty the hopper and run the grinder until nothing come out. Then weigh a dose of beans and grind them. Check what comes out. The usual problem initially and when the setting is changed is that it will be a touch light. Add a few more beans to make that up. It may just be one or two or accept some variation. Having checked loads of doses I had +/- 0.1g. It's down to bits of beans staying or not staying on top of the burrs. Hoover those out and the dose will be a little less than what went in until they build up again. There is also some permanent retention in the grinder. Clean that out and it will take much longer to settle down so it's best left unless the grinder starts choking up and has to be cleaned. If a different bean is used there will be a little carry over from the previous one. I just drank what came out. If you were silly enough to run vanilla flavoured beans through it you would notice the carry over. Others are pretty subtle. Another option is to just run say 25g of the new bean through it and throw them away.

When a hopper is used must waste X grams of grinds after an over night stand as the grinds will be stale. If so the same must be done if some one makes one in the morning and one in the evening. Why not try wasting and not wasting to find out?

Must have a minimum weight of beans in a hopper. Pretty true on flat burr grinders. From my use Sage ones don't much care until it gets very very low.

Beans go stale in hoppers. In practice there isn't much difference to keeping them in a vented bean can. A lot depends on how long they are in there just as it does just about any way they are stored apart from freezing.

Many of the problems in this area are down to the web and Sage's instructions for brewing aren't much help. If people don't meet them they say oh I'm over or under extracted. That can only be detected via taste not some rule. A fairly common comment on here when some one says that a bean is bitter is to grind a little finer and usually it will sweeten. Strange as that increases extraction. If time is fixed it also reduces the output  so if they stick with it they have under extracted so they stick with a ratio and extend time. People weigh out and vary time to achieve a ratio. You might be surprised how hard it is to set an exact ratio purely via the grinder setting on any grinder even the Niche is a bit tricky where I need to use it. I don't work that way and use a fixed button press. I didn't realise how much the BE was helping with that until I started using timed shots on the DB. Using a mazzer I had to allow time to vary by at least 5secs because that was the smallest adjustment I could make and that could be hit and miss.

Then ratio. Sage manuals mention one if ml is viewed as grams. Around 3 for the single and a little higher for the double because as they say the extraction can tend to be more efficient on larger baskets.  I found overloading the single a *little* fixed that on the BE. Then there are commercial baskets. 2 for doubles one holds 12 and the other 14g. 12 is a ratio of 5. I've never found a fresh roasted origin bean that needs to go that high. Plenty that need over 2. The aim is to achieve a balanced flavour and also one that suites the drinker. Beans vary so people are bound to find some that they don't like what ever they do with them. There is a lot of scope in that though and without going through the changes there is no way of knowing if the bean will ever suite the drinker.

Someone said a while ago that coffee brewing is getting too complicated. Blame the web. My impression is people leap in having read this and that and do all sorts without really knowing what effect they have or if they are needed. The same person all so said what about 40sec brews, something some do all of the time. Others do strange things with Sage DB's that make a nonsense of the usual rules. You might say it's all a matter of taste - it all is really.

LOL No point in posting this either as nothing will change.

John

-


----------



## Dodds25 (Dec 19, 2019)

I still think the steps are too far apart. I adjusted the internal ring down to 3 in the end and can now grind fine enough, but if I am on 4 on the external ring I am underextracting at 5:1 with 9g in the basket (at this grind level you can go a bit higher than that, but not much), whereas if I go to 3 on the external ring, I am overextracting at 2.2:1 with 8g (which is about the lowest you can go. I need a setting in between the two, but the machine doesn't offer one. I think they've addressed this in the Pro to some extent, but the steps are only a bit closer together.


----------

