How to get "muffin" to stay inflated/solid at no vac.

I have been making wax and oil for years. When I make wax, I ball my bho in the center of my vac. chamber and inflate a muffin. Sometimes it flattens out and you have to release vacuum and ball it back up tall and pull vac. again. However I watched a you-tube video of dude releasing vacuum and he had a fully inflated muffin. Hard as a rock. Video was cut up and vague as far as temps and pressures ect. He was def. handling a hardened inflated bho muffin with his bare hands. What kind of witchcraft is this?