I know this thread hasn’t been active, but hope I can still get some feedback. I’m curious about kettle material in this build. Seems aluminum is good when heat source is external due to thermal properties, but may fight against us when heat source is internal as it may lead to more heat escaping. Do you think SS is best for electric kettles? Is the heat transfer out of aluminum negligible? I know jkarp insulated his aluminum kettle in the original build. I assume for these reasons. Would it be necessary to do the same with a SS kettle?