Methane has no odor, which is why your gas company has to mercaptans to the gas so you can smell it.
PURE methane has no odor, but a lot of times it isn’t pure and the stuff that is mixed with it stinks.
WOW Karl......I think I was drinking too much wine the night of my post. I do know better as I owned a propane company for many years.
You did cause me to do some further investigation along the lines of my gaseous thinking that night. I found some interesting reading on the subject at this site
http://www.heptune.com/farts.html