The pre-Christmas rush provided me with a lot of hard work and a good deal of food for thought. The background to this article is simple; in early November I received a long awaited shipment of Rancilio Silvia espresso machines at the same time that I ran out of stock of Quaha machines. In the following 6 weeks I set up and tested over 80 Silvias, in batches of 6 at a time.
When you need a precise grind, only the best will
When you need a precise grind, only the best will do.
All the components used in brewing, machine, portafilter and filter baskets, need to be at a stable temperature. The best way to achieve this is to let everything heat up together for at least an hour. Leaving the machine on overnight or longer is not a problem as long as the boiler is full and there are no leaks from the steam wand, solenoid etc.
A little bit more or less coffee makes a huge difference. Once I’d worked out the temperature thing, this turned out to be the biggest single source of variation. As little as 0.5 gram of coffee can make the difference between an ordinary shot and espresso nirvana.
Too much coffee?
very well defined screw impression in the puck.
A very well defined screw impression in the puck.
Tamp not a factor
One thing that putting as much coffee in as possible did was to remove the effects of tamping as a factor in the shot quality. A light “smoothing” tamp to remove voids and ensure good edge contact with the filter basket was just as effective (or not) as the heaviest “grunt” tamp I could manage. To prove to myself that this situation wasn’t exclusive to the Silvia, I tried the same thing out on a 1-group La Marzocco and got the same results.
Leaving your machine on for extended periods more or less duplicates commercial practice, but certainly uses more electricity and will lead to faster deterioration of the group gasket. Using as much coffee as possible in the filter basket may lead to wear or damage of the showerscreen assembly (although I haven’t seen any) and certainly requires a strict showerscreen cleaning regime.