I'm surprised no one else is reporting this, but I just built a small cooling room, added some wheeze worts and within a minute the room was a complete vacuum.
When I uprooted the wheeze wort though I got all the gas back in a canister.
So it looks like they're eating gas but instead it is just storing a huge amount of gas I guess.
build a small gas tight room with gas in it.
Plant a wheeze wort in it.
The room will go to vacuum very quickly