[cherry]

re Propane....is it stable enough to store....can you buy now and will it keep until next winter?

[stars & stripes forever]

Does Propane Go Bad - Propane Shelf Life - How Long Can ...

Different from fuel types that degrade with time, like gasoline and diesel, propane fuel does not expire nor does its effectiveness deteriorate with time. You can store propane forever, if you are talking about the gas itself. Propane tanks typically need re-inspection every 10 years.

https://www.elgas.com.au/blog/1995-does-lpg-propane-go-bad-shelf-life-diesel-petrol-shelf-life#:~:text=Different%20from%20fuel%20types%20that%20degrade%20with%20time%2C,Propane%20tanks%20typically%20need%20re-ispection%20every%2010%20years.