Still, a square piece of plastic is still more portable than carrying around a 2 liter bottle full of fermenting yeast. I'm not about to strap that to my backpack when I go hiking.

That was interesting, except I don't understand why it calls for a candy thermometer when the highest temperature you are asked to measure is 90 F. The first temperature where sugar does something interesting in candy making is 230 F, and so many candy thermometers don't even go down to 90 F.