I bought two plasic big mouth bubbler fermenters with the dual port top. I also bought a stainless steel thermowell to put in the second port of the lid so I can monitor and adjust the wort temperature during fermentation. Do I have to put liquid or silicon paste in the thermowell for it work properly or will it propoerly conduct temperature with just air it it? I also have a conical fermenter with a thermowell and the manufacturer recommended puting silicon thermal paste in it which is the reason for my confusion. Any answers, thoughts would be appreciated.