Cooling down a lever.
One of the flaws with a lever machine is that most of them, such as the La Pavoni models and the Elektra models is that they tend to overheat after a few shots. The design is set up so that the water is too hot for espresso (so that the tank can steam as soon as you are done pulling your shot and you do not have to wait for it to heat up the way you would with a traditional single boiler machine) , but the grouphead is cooler and acts as a heat sink cooling off the water as it heads for the espresso. The problem is that with each shot the group head loses some of its ability to cool the water and so the temperature is higher for each shot than the previous shot. With the Pavoni I am usually able to pull roughly two good shots that are not too hot or too cool to taste good.
One proposed solution is that of taking a towel filled with ice and placing it on the grouphead to cool it off so that you can continue pulling shots at the lower temperature. Another is just running cold water over the portafilter to cool it off and see If that in turn can cool off the grouphead. This second method does not work for me, but that is in part because I chopped my portafilter so it does not have the mass necessary to be very effective in cooling the group.
I decided to test the cooling with ice yesterday. It did work okay, but I was never quite able to hit the mark as well using this strategy as I could when starting from scratch. It was certainly better than just pulling shots without cooling, but I never loved any of the shots I pulled.
A friend has offered me a temperature strip that lets you gauge the temperature of the grouphead and this may help solve the problem. I am eager to try it out and I will post with the success. I do not know how accurate the strips are, but they seem like a very clever idea. Here is a link to the strips…http://www.orphanespresso.com/Pennys-Hot-Shot-Group-Strip-Thermometer_p_2133.html
I am excited to try them. None the less I think the ice trick won't ever be my favorite as it seems like too much of an ordeal and you can cool the whole machine off and heat it back up in 30-45 minutes, so that seems like a more natural solution if I need more than two shots for company.