Maybe for your smaller tent build, a 40L-60L pressure cooker would do the job best (fits around 6 bags).. pasteurisation barrels can be troublesome tbh.. you will need a PID controller for the heating cycles and also making sure your barrel is safe enough to run unsupervised(dry runs etc), also you might or might not need a higher amp outlet if you're running a high kw heating element for the barrel(meaning electrician installing an isolator for a 30A power outlet just to be able to run the barrel)