Originally Posted by ODaniel
Important thing I learned about thermometers:
If you use digital, make sure it is at least 8" long. Grill thermometers have about a 3" probe. I was having FG issues, so I got another thermometer, a lab type ($5 at LHBS) and there was about a 10 degree difference in thermometers, due to the amount of penetration. They read the exact same if at the same depth btw. The digital just can go down far enough to get a good reading. Make sure whatever you get, get a long thermometer.
Maybe, but be careful here. Lab-type thermometers come in two different types: partial immersion and total immersion. Partial immersion will have a line printed all the way around between the bulb and where temp gradations begin. The fluid level should be at this line for proper measurement.
If the lab-type thermo in this pic is partial immersion, it is probably reading high.