James, there is a lot of good information in this recent post:
But in a nutshell, viability goes down very quickly at room temps after the pollen is dried, and keeping it at the lowest freezer temp you can muster will prolong viability the best. I’m very small time, and use small cheap cosmetics jars (Amazon) for every flower I harvest, although it might hold 2 or 3 flowers worth of undried anthers. I dry 24 hours, or until the pollen bursts, and then either use immediately or freeze. These jars are also just the right size to wrap an index finger around, while holding tweezers or a brush in the other.
https://www.amazon.com/dp/B00TT70OME?psc=1&ref=ppx_yo2ov_dt_b_product_details
