diggi Senior Member Joined: 28 Nov 2011 Posts: 235 Location: Halifax, NS Expertise: I love coffee
Espresso: Spaz vivaldi S1 V2 Grinder: B Vario, Hario Mini Drip: Chemex, Aeropress Roaster: Poppery I
Posted Sun Feb 5, 2012, 12:57pm Subject: yet another silvia OPV adjustment thread
I know this has been hashed and rehashed, but I'm having difficulty finding a nice, concise source of information regarding the adjustment of silvia's OPV. I've done extensive reading on this subject but I don't really have a plan worked out yet.
I have been very satisfied with silvia to this point, but I have been encountering a few issues that I'd like to change:
I can't use the triple basket. Tried many doses/tamps but can't get it right. Just a big gusher with channeling or clog the machine. I think this could be helped by reducing the stock 11 bar silvia OPV (increased on V3 to accomodate pod's).
I've been moving toward ristrettos and have had some success. 1 of which I would call a god shot (but being my first, the bar was set quite low).... now I'm finding a bit bitter and can't fix with dose adjustment. Also very difficult to get consistent grind results (I know this is to be expected with silvia) but I think that bringing OPV down to the 'correct' range may give me a leg up here.
Unless you think I'm way off the mark, I just need a plan for going about this adjustment. I don't have a pressure guage. I can figure stuff out fairly quickly, but I'm not really what you'd call handy. I own tools (and even bought nice dewalt drills etc, just to make others think I was 'handy') but ... they don't get used that often. Am I going to get over my head here, or is this something I can figure out. I won't be broke if I break this machine (but I'd prefer not to) and likely couldn't convince my wife to let me replace it for another couple years if I did make it unusable....so
Should I take this project on.... I'd like to think I'm capable.
Is my reasoning correct for justifying this project.
How should I go about it? Do I need a guage, or can I just use flow rate? Any links to a concise thread or mod done previously.
JGG Senior Member Joined: 31 Mar 2006 Posts: 1,294 Location: Kentucky, US Expertise: I like coffee
Espresso: PID Silvia; PID Alexia Grinder: Mazzer Mini E (A), SJ; Rocky... Roaster: Hottop D w/PID; Thermometric...
Posted Sun Feb 5, 2012, 3:59pm Subject: Re: yet another silvia OPV adjustment thread
Pretty easy to do, but don't try it without a pressure gauge. Loosen the jam nut, loosen (or tighten if you need to increase the pressure later) the adjusting nut, then retighten the jam nut. Pictures here: http://pidkits.com/opv.html
Posted Sun Feb 5, 2012, 10:51pm Subject: Re: yet another silvia OPV adjustment thread
I am a bit perplexed over your statements that even with a quality, stepless grinder, that you cannot get a decent extraction, and the extremes are channeling gushers or choked. While a lower setting on the OPV may assist in taste, I am not so convinced that there may be other problems here concerning consistent dose and distribution that may also be factors. I do not discourage you in pursuing a gauge and a resetting of the OPV. Yet I would not preclude that there are other problems that also need to be addressed. Such as, what coffee are you using? Possibly also a .1gram scale to quantify the dose would also be helpful, if for no other reason than to limit coffee waste.
diggi Senior Member Joined: 28 Nov 2011 Posts: 235 Location: Halifax, NS Expertise: I love coffee
Espresso: Spaz vivaldi S1 V2 Grinder: B Vario, Hario Mini Drip: Chemex, Aeropress Roaster: Poppery I
Posted Mon Feb 6, 2012, 3:53am Subject: Re: yet another silvia OPV adjustment thread
I appreciate your reply.
frcn Said:
I am a bit perplexed over your statements that even with a quality, stepless grinder, that you cannot get a decent extraction, and the extremes are channeling gushers or choked.
I'm only having these issues with the triple basket. These are non issues with the double basket. Have you ever tried pulling a ristretto shot at 11+bar with a triple basket and had success?....I don't know if you have, but I'm guessing this is not the optimal set up for a quality shot. Maybe after adjustment, I'll still be unable to use the triple successfully, but here's to hoping it'll help. So you don't have to bring it up, TonyVan may have this reply:
Have one. Sometimes use it and sometimes dose by volume. Use doses as high as 18g, but now I'm settling closer to 17g. (18-21 with triple)
I just don't see any pages with "instructions on adjusting your OPV". I think I could 'wing it', but the real stumper is what I should be looking for for a guage. I have come across some home-made units (without plans for construction), but these all seem quite daunting.
Although I DIY on lots of stuff, I wimped out and just bought one from Chris' Coffee. But I recall reading a bunch of posts here on CG describing various good ways to build one for cheap.
My only advice would be to use a liquid filled gauge if you can get one at a reasonable cost. The vibe pump can make the needle pretty jumpy.
diggi Senior Member Joined: 28 Nov 2011 Posts: 235 Location: Halifax, NS Expertise: I love coffee
Espresso: Spaz vivaldi S1 V2 Grinder: B Vario, Hario Mini Drip: Chemex, Aeropress Roaster: Poppery I
Posted Tue Feb 7, 2012, 3:47am Subject: Re: yet another silvia OPV adjustment thread
Thanks everyone for replies. I've been checking out those links and after looking at the pre-fab models for sale, they actually look fairly easy to construct (hence all the DIY examples on HB). I think I'll take the plunge soon. All the gauges don't seem rated for the proper temperature. Is this a problem? I'm guessing not, since they've been used extensively by others (and only at high temp for relatively short periods of time). This one click here for instance seems to fit the bill, but shipping is as much as the gauge itself....I'll look locally first. So finding the appropriate fittings may be a whole day affair and would most agree that a needle valve is a good idea? Or is this unlikely to change my settings much anyway (given I have a vibe pump and variation anyway)
JGG Senior Member Joined: 31 Mar 2006 Posts: 1,294 Location: Kentucky, US Expertise: I like coffee
Espresso: PID Silvia; PID Alexia Grinder: Mazzer Mini E (A), SJ; Rocky... Roaster: Hottop D w/PID; Thermometric...
Posted Tue Feb 7, 2012, 7:29am Subject: Re: yet another silvia OPV adjustment thread
The needle valve would be nice to have. But you can also get the same effect by slightly opening the steam wand.
What you are trying to simulate is water passing through the OPV. There is a relationship between pressure and the amount of flow shunted through the OPV. You should see slightly lower pressures with the steam wand cracked versus a pure "deadhead" condition.
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