aasemkhan wrote:I was recently introduced to the joys of home made espresso and have just purchased a used La Pavoni brass model (Two switch). I LOVE this machine. I may not have reached espresso Zen yet, but I'm pulling respectable shots with it.
I saw this quote at the top of a thread on polishing copper and brass on a vintage dual switch La Pavoni Europiccola. Since it's off topic, I thought I'd post these tips in a separate thread and link to it. I've been in the Zen zone (the alliteration was too tempting) recently with my dual switch Pavoni. To get there I equipped it with a group thermometer and inserted an Elektra double basket, which takes a higher dose than the stock Pavoni one. On my machine I had to chop the portafilter to fit that basket but some pre-Millennium portafilters will accommodate that basket internally. I've also added a pressure gauge on top of the sightglass. These are available at Orphan Espresso. This yields completely observable boiler pressure and group temperature. I've also added a Teflon gasket between the group and the boiler to slow temperature transfer. I've dialed in a Mazzer Super Jolly so that I dose about 16.5 to 17 gm with a fine grind that I tamp only to level. The Pavoni double basket will take a slightly smaller dose but should work fine.
Here is how to do this for a single shot. I've added instructions below for temperature controlling multiple shots. I turn on both switches and when the overpressure valve starts to vent I switch on the thermometer and then watch the temperature rise on the group. I also do a brief flush to heat the group. I do some half pumps to allow steam into the top of the group. As I approach target temperature I lock in the portafilter. The half pumps don't raise the lever high enough to pre-infuse the coffee. When it gets within 2 or 3 degrees F to the target starting temperature I toggle off both switches. Without a Teflon gasket you may need to give it a little more leeway, maybe toggling off 5 degrees before target. I do one or more half pumps to get to a predetermined temperature. I then raise the lever all the way and it stays put by itself while it pre-infuses. When drops hit the cup and start to slow, this means the grounds are expanding as they absorb water. Then I do about a 20 second pull that feels like cutting through frozen butter. I don't raise the lever and pull through again. This consistently yields rich shots that taste like they were pulled on a La Marzocco machine in a fine cafe. With very bright, light roasted beans I start the pull with the group temperature reading (outside back of the bell) as high as 198F. With a darker roast but not one into second crack I may start at 193F. Coffees like Stumptown Hairbender like lower temp like that. Coffees roasted into second crack will require a much lower start temperature* to tame the bitterness. The thermometer's the most important part of this routine. The thermometer I used costs $10. The shots are completely consistent because temperature is controlled. Here are two reference links:
Adding Thermometry to a La Pavoni Europiccola
Creating Teflon Gasket for Pre-Millennium La Pavoni
Converting the Portafilter to Bottomless
I'm pulling a shot at a time and haven't recently tried pulling back-to-back shots with this machine but expect that doing so will require varying when I toggle off before reaching target temperature on a machine that's heated up. Steaming milk with the High switch on will also raise group temperature and require cooling time, but these shots are so good I'm not using milk.
* Added: Such coffees do better with the internal 175F temperature Alan Adler recommends people use with the AeroPress. I would try targeting about 170F on the outside of the group bell for these. If it still has a bitter edge, try a little cooler. Robert Pavlis, who posts below, suggests in another thread that if you have a Robusta or a dark roast you can layer it on top of a lighter roast to filter out the harsher components while benefiting from other rich flavors these may confer.