The interior is stainless steel, and the lid fits tight

I have not, and do not intend to, use this product directly on a stove-top to heat water, and therefore cannot speak to its performance in that regard.)I recently replaced my defective 1 L Bonavita gooseneck electric pour-over kettle with the 1.7 L Cuisinart PerfectTemp cordless electric kettle, the Rolls-Royce of electric tea kettles for variable temperature control