I have never weigh one but a full canner is all I can lift so I expect 30 to 35 lbs. You have 7 qt jars with a pound or more of food in each one, the water about 3 to 4 qts. So the weight is part of the problem but the circumference of the canner can cause problems with uneven heat distribution. All canner companies will tell you not to can on a glass top.