It does defy logic. When I posted on Facebook that I was going to try the infamous "boiled peanuts in a crockpot" technique, I had a friend immediately post, "It's not gonna work. You need a rolling boil. Crockpots are great for keeping them warm but not for cooking them."
But guess what? It works!
It turns out a crockpot on high is about equivalent to a simmering boil, and that's obviously all you need. (This also fixes the tendency of some to literally boil the hell out of the peanuts until they lose all peanut-like consistency...unless that's your thang, of course.)
I modified this recipe because I only had 2 lbs. of peanuts. I recommend only two pounds too. I have the huge crockpot and, with water, two pounds was close to the limit.
The great thing about this discovery? Thursday night football! Wash your peanuts and put them in the crockpot. Put 3/8 cup of salt on top of the peanuts (or more or less, depending on how you like them). Fill the crockpot with water as far up as you feel safe leaving it on high. Put it on high when you go to work and switch it to keep warm when you get home! (This time, I cooked mine on high for seven hours and switched to keep warm overnight because I was too lazy to fool with them before bed.)
Lagniappe: An elderly lady at the grocery story was picking through the peanuts very carefully. Of course, I had to ask - and I'm glad I did. Seems that the ones that I've always thought looked almost dried are the ones that you need to find. The wetter, darker ones (that I always thought were the ones I wanted) are the ones that cook to mush in the end. Honestly, I didn't quite believe her but she seemed like she knew more than me, for sure, so I tried it. She was right! Pick out the ones that look almost dried and use those. I have 2 lbs. now of boiled peanuts and not one pound of peanuts and the other of boiled mush in shells!