Jan 23, 2007

What's an OPV?

Nope, it's not an acronymn for my favourite Vietnamese soup, nor is it a bike part, so what's left... hmmmmm if you guessed coffee you are halfway there. OPV = Over Pressure Valve, an often overlooked hunk of brass that can have a very big effect on that espresso shot you are savouring as you lift it up for that first sip. It's a coffee machine part, more on that in a sec...

As you can imagine I have roasted up a few batches since we got back, two for the neighbours and five batches for us. The batch I was interested in I roasted up for espresso on the Brewtus II, it is a Brazilian Beccor Lot 141 and some Ethiopian Harar Grade 5 in a 70/30 split. Anticipating some spicy chocolate love at five days into post-roast I pulled a shot into one of these little (and very inexpensive) two ounce demitasse I bought at one of the markets in Hanoi. It was hard to pass them up as I really liked the handmade effect and the rich, vibrant red interior. After much haggling I grabbed four of the demitasse and four six ounce latte mugs for $8.00Cdn but I suppose that's another story...

As I watched the shot I was a bit concerned. I tasted the shot - blacchhhhh! A grind adjustment and a minor updose and pull a second shot this time watching the pressure guage, yikes check out the pressure! Over-pressure, way over-pressure, 14bar now that's over-pressure. Over-pressure = bitter, harsh, not world-class espresso (and world-class is what I was looking forward to). Uuugh!

So I just fired off an email to my local guy, Peter of Cappuccino King, to see if he has an OPV in stock that will mate up with the Brewtus II. If not I will have to wait until I get one from the company in the US. Oh well, it's not too bad, there's still a whole lot of Aeropress to be done; particularly since I'm experimenting with a new process involving a 5mm FDA grade poly filter (as opposed to the paper filter) and an inverted brewing method - which is working out very well. And with an Aeropress mug of Lot 141 and Grade 5 blend now finished while I typed this up, I'm off to throw on a Winnie the Pooh DVD so I can get in an hour ride on the CompuTrainer.