What Is "too Hot"

Are you talking about degreasing or maceration or both? We primarily do whitetail deer skulls...We do 90-100 on maceration and 115-120 degreasing. I had a thermostat go out on one of my degreasing tanks and when I found it the temp was around 170degress and had been for a couple days. Those skulls turned out just fine.

With that said, I found no noticeable difference in degreasing a skull at 110 or 120, and the ones that were at 170, weren't any better. I don't see a need to go higher with the temp.

 

Maceration needs to be 80 to 100, preferably less than 100, more like 90 as higher temps are just not conducive to a good growth of bacteria. 120 is all that is needed for deer and other cervids. They have a harder tallow and not the soft fat of other animals. The higher you go, the more energy you are putting into the project. Water boils at 200 degrees, 185 would be a simmer. You don't want to get anywhere near those temps because you are now cooking the bone, damaging it and possibly driving grease deeper into the bone instead of removing it.

 

Would say that 165 is too high and not needed 120 is fine and I really wouldn't go over 130/140 if you were testing. Boiled skulls are already compromised and high heat will just continue the degradation of the bone.