temperature probe set point

So my new routine is to tape the temperature probe from my dual stage controller to the side of my carboy with some insulation in it. I'm assuming that set up like this, I'll be reading closer to the internal temp. That being said. Should I set my controller to the exact degree that I want to ferment at? or should I set it a little below and assume that fermentation will be a little warmer than what my probe reads. (i.e. if I want to ferment at 64, set the controller to 62).

A few comments that may be of use.

There will always be some undershoot during a cooling cycle and overshoot during a heating cycle. Determine what these values are for your setup. Select your differential value a smidge above the highest of the two so you don't have the two cycles fighting one another. Unless your heater is oversized, these values should be fairly close to one another. This will result in your set temp being the average temperature of the wort through the cycle. The average temperature being your desired fermentation temperature.

You can always check out the Thermowell stopper from MoreBeer. I have one and love it. It maintains the temperature in the center of the wort.

http://morebeer.com/products/stopper-thermowell.html

Funny you mention that. I have one. Doesn't fit a carboy at all. It pops right back out and doesn't seal.

I took my 6.5 gallon bucket, got a new lid, cut a hole in the top with a spade bit. Problem solved. works like a charm.

The method you use has worked very well for me for a couple of years, with one small process adjustment. I almost completely ignore the numbers on the dial on my controller. In addition to attaching the bulb to the Better Bottle, I put a good thermometer along side it. I adjust the dial to maintain the temp I need, as read from the thermometer on the Better Bottle. Think of the dial as the gas pedal and the thermometer as the speedometer. Sounds like it would be tricky, but it's really very easy if you check in on the fermentation chamber from time to time as I do. If you're a "set and forget" brewer it won't work, but my experience with my controller is that that approach just won't deliver the results that I want.

is the thermometer your using the kind that reads ambient temps? or a lab thermometer?

Sgraham, I use a large dial analog thermometer that has been calibrated to water's boiling and freezing points. I usually have a "Fermometer" affixed to the Better Bottle as a double check, and I find that they are quite close.