Wenn du dann soweit bist, Stefan...



When making espresso there are a number of variables that should be controlled to as great of an extent as possible. We often discuss controlling the grind and the brew time as well as the tamp procedure and pressure as key factors. Two other key factors are water pressure and water temperature. For most of us there is not a lot we can do about directly controlling pressure, but there are some tricks that can be used for manipulating the brewing temperature even when our machine does not offer a specific control over that variable.

Back in February 1, 2001, Greg Scace posted to Usenet on alt.coffee his findings from experiments he did with his Silvia using a digital thermometer device [entitled "Temperature study of my Sylvia (looong)"]. He used a process to control the temperature (outlined below) and charted his findings. From these we were able to see that the Rancilio Silvia can pull a shot with a temperature stability that was generally heretofore not thought possible from a home machine of such a (relatively) humble price point. Many thanks go to Greg for doing the testing and documentation to show the value of the process.

I document here how I have applied what Greg taught us when I brew espresso. I now use this process for every espresso I create:

1) Allow machine to come to full operating temperature. I usually try to allow an hour or so. The PF should be too hot to comfortably touch for more than a second from the heat conducted by the brewhead. The time will probably vary from machine to machine and home to home, but plan on an hour or more. Of course, you should always leave Silvia with a full boiler at the end of one session so that when the next session begins you can leave her on for an extended period without fear of running the boiler dry. Be sure that the steam valve is completely closed.

2) Once she is fully warmed up, grind, dose, tamp, lock and load. Position your glass under the PF, ready for the shot.

3) Hold your steaming pitcher or other suitable vessel under the steam wand to catch the water and open the steam valve.

4) Turn on the hot water switch. Leave it on until the heating lamp comes on indicating that the brew thermostat has been closed and the heating element is heating the water. This does three things: it bleeds the system of steam, brings the water in the boiler to about the same starting temperature each time you are about to pull a shot and it turns on the heating element. *1

5) The instant the light comes on do the following things as simultaneously as possible:
A) Turn off the hot-water switch.
B) Begin timing. I have a clock on the wall with only a second hand (I have removed the hour and minute hands) specifically for this purpose.
C) Close the steam valve.

6) Have your finger on the brew switch and when your timing (from "5B") shows your pre-determined time has elapsed, begin the pull by turning on the Brew switch.

I have tried 20, 30, and 40 seconds, and at this point, my machine and palate seem to like 30 to 40 seconds, but experiment with yours to see what works for you. Later Silvias (fomr mid to late 2001 and newer) with the cooler thermostat seem to like as much as 50 to 60 seconds.

What I can say is that since I started using this procedure my shots have been amazingly consistent. Try it and see for yourself.