I've recently switched over for the cold weather to a makeshift scuttle (ceramic mug kept in a sink of hot water). The warm lather is just a great feeling, but I have noticed lately my lathers are wetter/looser than they used to be. I can't think of anything I'm doing differently compared to before, other than the mug, and keeping it warm. Is it the warmth? Or perhaps the lack of any texture on the inside of the mug (it's ceramic and glazed pretty much glass smooth).