In the mid -'80's, the two most popular soft drink manufacturers provided their product in 16-oz. glass bottles.These worked very well.I, being stupid, placed a tin can lid on the hot-plate and the bottle on top of it.Never did I have a bottle to break...if heated slowly to the desired temp.Today...we have the Ya-Hoo chocolate drink available in 16-oz. glass bottles, and I've also descovered the oil bath.Again,no popped bottles if heated from room temp to target temp, gradually. This is Not pyrex...so don't immerse the bottle in 150*F. oil suddenly...you will get a cracked bottle.As a point of information...I neglected to be there during the whole thing and when I returned...my CANDY Thermometer read 500* F. and a cloud of vegetable oil hung over the whole scenario...but, like the "Eternal Phallis' symbol that it is...my YA-Hoo bottle was stil erect and intact.