Silvia OPV adjustment question

alastair

Thanks to GRINDER*MAN I've a pressure gauge to sort out my Silvia problems.
Without any (further) adjustments, it's operating at 9.5 bar. Not too surprised tbh, as I've produced a couple of cappuccinos that passed the quality test for the woman of the house today and yesterday - changing the beans made all the difference.

My question - do you need to let the machine warm up and take another reading, or will cold machine operating pressure be the same as hot?

Mr Magnolia

I'd let it warm up to check it. Everything expands under heat so the pressure may be higher when heated than when cold. There may not be much in it but I'd check it for curiosity's sake if nothing else.

alastair

It's pretty much at brewing temp now (I ran a bunch of backflush cleaner through it) and still at the same pressure - probably closer to 9 than than 9.5. I think I'll leave well enough alone now.

Clearly those bags of Hair Bender had some sort of voodoo going on. I'll have to pull the other bag out of the freezer and see how it tastes. But so far - Hair Bender = bitter, dodgy old bag of Java Republic Munkey = bitter, Aida's Grand Reserve = not bitter.

RE*AC*TOR

Drop it down to 8.5. Will be worth it.

alastair

RE*AC*TOR wrote: »

Drop it down to 8.5. Will be worth it.

I thought 9 bar was the ideal? What's that extra inch going to do for me?

RE*AC*TOR

Extra 1 bar can make a big difference. Fuller body, balanced flavours etc.

Also, if Munkey is coming out as bitter I'd say your brew temp is too high. I don't remember anything bitter in there. Mind you it has been a long time. Aida's isn't really an espresso coffee.

alastair

RE*AC*TOR wrote: »

Also, if Munkey is coming out as bitter I'd say your brew temp is too high. I don't remember anything bitter in there. Mind you it has been a long time. Aida's isn't really an espresso coffee.

I've set the PID to 103 C - which, according to Auber translates to a grouphead temp of 94 C. Too high, do you think?

RE*AC*TOR

It depends on the coffee.

Worth bumping it down by two degrees and seeing if it makes a difference. It is possible the batch / beans of Munkey are bitter of course - it's just not something I remember from tasting them.

Mr Magnolia

Some of the munkey beans i've tried have certainly had a bitter hue. They were sent to me 2/3 months post roast which would have contributed to this. What's the roast date on the beans alastair?

alastair

Mr Magnolia wrote: »

Some of the munkey beans i've tried have certainly had a bitter hue. They were sent to me 2/3 months post roast which would have contributed to this. What's the roast date on the beans alastair?

The bag's gone now, but I think they were roasted in December, opened last week.

OVP now knoocked down to 8.5 bar and temp down to 101 C (92 C at grouphead) - we'll see what that does in an hour.

alastair

Silvia update:

Leaving the pressure at 8.5 - 8.75 bar, but bumped the boiler temp back up to 104 C - better results than lower temps (on some home roast Guatemalan beans).