Although indicated by the title, PIDs do not actually have a taste of their own- any more or less than any other electrical device. This test was to show whether or not the adjustment of the PID's set point affects the taste of the espresso made with a Silvia. I attempted to test a range of temperatures with the PID equipped Silvia this morning. It has been a few hours since the testing ended, but I can still feel the residual effects of caffeine overindulgence.

      Testing will be ongoing. There are so many other variables that it is difficult to control everything and vary only temperature. Just getting a grind/dose/tamp the exact same every time for six or eight consecutive doubles can be a challenge for us non-professionals.

      I did learn that my house blend and roast is more suited for milk-based drinks than for straight consumption. It's not terribly exciting, has little in the way of varietal flavor, and the dark roast (I take it into active second with a few drops of oil showing after ejection) can be a bit much straight for my personal taste. Yes, some roast a lot darker with a lot more oil showing, and that's fine if that's what you like.. I generally don't. Moving on-

      I tried about six different pulls after the morning's coffees were consumed. The ranges I tested included the following temperatures in this order:

232
234
229
225
236
232

      To generalize I found the following- The low temperature shots were unspectacular. My impression of the 229 was "cardboard." Don't know why, but that's what I tasted behind it. The 225 had a bit of a bite to the finish and was unspectacular with nothing to recommend it. The 234 shot was OK, with very little bitterness behind it, but not real special. The 236 was over-extracted and had an indescribable taste behind it- words like industrial, plastic, solvent, cleaning fluid, or such bounced around in my head, but I couldn't place it. The 232 shots were the best. They had a touch of a chocolaty aroma deep inside them with a hint of it in the taste and low bitterness in the follow.

      I will say that I need to get some quality green, pre-blended for straight espresso and test that, but even with this simple blend I used for this test (6 parts Sumatran, 3 parts Colombian, 1 part Costa Rican) I could taste the difference in the shots as I varied the temperatures. Could I do it in a blind taste test? Not likely. My palate has not had the training for that. At least to say that I couldn't tell you "this one was too hot," or, "this one was too cold." Who the heck do you think I am? Goldilocks!?

      On the other hand, with a different, darker-than-normal roast, I pulled at 232 and found that the taste was quite dark, the taste of the roast over-powering the taste of the coffee. The next day I dropped the temp to 228 and the taste was much smoother and richer. Another thing I have noticed since the installation of the PID is that the under-extracted, bitter shots are no longer a problem. I have to assume that these were a result of underextraction caused by low brew temperatures. In other words, temp surfing works to some extent but isn't dependable. PID works all the time and is extremely repeatable.

      The fact that over a twelve degree range (225-236) I was able to discern the different tastes isn't terribly remarkable in itself, but does seem to indicate that the installation of a PID is a good one. Let's remember that in preparation, the key to quality espresso is control of the variables:

Grind
Dose
Tamp
Water Temperature
Water Pressure
Time

      A PID on a Silvia seems to be a great way to control temperature and a lot more economical than spending huge amounts on a double boiler machine (which may or may not get you better temperature control and stability).