I want to knit a tea cosy like shown in this picture (not affiliated; image source):
I want it to give proper insulation to my tea pot to keep the contents warm for longer. Originally I planned on using the English Rib pattern (aka Patentmuster in German), but seeing it now I'm uncertain how well it actually insulates. Due to its stretchyness it seems like a quite loose pattern.
Are there any knitting patterns that are known to be very well insulating? I would prefer to knit only with one strand, but I can do 2 strands if I must.