Pressure

Pressure is determined by the power of the vacuum packer. The vacuum packer extracts air from the sous vide bag, squeezing the bag tightly against the food, sometimes even compressing the food. The questions to ask in order to determine the desired pressure are these: Do you want the item sealed very, very tightly or even compressed? Or is the item so delicate that it will be crushed by too much pressure? Is there a bone that might puncture the bag if too much pressure is used?

Chamber vacuum packers typically have one gauge for the amount of pressure and a second gauge for the duration of packing. Because vacuum-packing machines vary, general settings for packing are recommended (low, medium, and high) in the recipes here. Many factors determine the appropriate pressure; sealing time is determined by the thickness of the bag. The gauge on the packing bar records how hot it gets. Thicker bags need more heat to fuse completely.