Heat Source

Has anyone used an induction cooktop for brewing?

there's probably no reason why it couldn't work. However, it takes a lot of heat to boil 6 gallons of water, so you will need a fairly high wattage unit, just as if you were brewing on a regular electric stove.

Also keep in mind that the cheaper stainless kettles probably don't work well on induction cooktops. Induction cooktops work by inducing electromagnetic fields into magnetic metal, and it helps to have a lot of that metal. If a magnet doesn't stick firmly to the bottom of your kettle, you probably won't get past a simmer - some stainless steel is not particularly magnetic. You'd want one of the ritzier thick bottom kettles as well, for best efficiency.

I tried that when canning with about four gallons of water an it was tough to keep a boil I would imagine brewing would be worse since you are maintaining a certain temp. The ceiling fans an ac affected ours.

Just try it with water as a dry run. I was also scared of all that weight on the stove and cracking it.

I ended up getting a propane burner.