Okay I have had my flat top for approx 12 yrs now and can on it every season but here is the catch. My caner only holds 4 quart jars not the huge 7 jar caner. In the book it talks about aluminum, cast iron and copper bottom pots. The copper bottom pots, aluminum are both conductors of electricity and can make the element under hotter then it is to be and will crack it and the cast iron pretty much the same way. I can do a run of green beans and have another one ready to start by the time it takes to do a run and them to cool off by using the 4 quart caner and mother is only getting 7 quarts done and it only taking about 5 minutes more. The 4 quart are hard to fine and I have had mine about 20 yrs. Hope this helps