Just had a most instructive weekend.
I've been producing thin, bitter stuff since installing the PID and farting about around the 102C mark, messing with tamp and pack to no avail.
I started using a spreadsheet to record temps at the thermocouple throughout the pull...
Look. If you're going to laugh, I'm going to get all huffy and walk out :)
As long as the machine had heated for a while (I've had mine on a timer for ages so it wakes up an hour before I do then puts itself to bed, waking only to preheat for a mid morning double and the post lunch livener) temperature at the thermocouple would drop by around 10 degrees during the 22 second pull.
Then I worked out the difference between temperature and heat and started using my laser thermometer (stop bloody sniggering at the back!) to check the temperature at the brew face. Crucially, while the PID read out a drop from 102 to 92 near the heating element, the temp at the coffee surface remained a consistent 97. This, I guess, is the advantage of the brassy mass of the Silvia - it holds heat.
Anyhoo, I leaped on one of the Baristas at Borough Monmouth on Saturday and asked what the temp was at his brew face. He laughed at my geekiness, pointed me out to his friends, raised his eyebrows and made several humiliating asides before gazing straight into my eye and whispering "87, plus or minus 2" - such is the tragic, secretive cameraderie of the truly afflicted.
I immediately dropped my PID temp to 92 and, on first pull, produced the kind of sustained, self-supporting crema that a pornstar would describe as 'Serious Wood' - about 7mm deep, tiger-striped and wouldn't quit after a minute of waiting.
Now I'm messing with pack and tamp but, frankly, it's making much less difference - really just refining.
Up till now, I've been buying my stuff preground from Monmouth for consistency and freezing it in 100g baggies so it looks like I'm going to be asking Santa for Mazzer to further perfect my life.
Why on Earth didn't I start a cheaper habit - like crack
Edited by Tim Hayward, 28 October 2007 - 01:29 PM.