Fellow Joule owners, try this if you're interested in minimizing evaporation from your water bath. This should work with any polyethylene lid and utilizes tools that you most likely already have on hand. Gather the following: blowtorch, crappy dinner knife, 48mm round cutter. Warm the edge of the cutter w/ torch and carefully melt the lid in your desired location. Do the same thing with the knife for straight cuts. Easy as pie.