How long can you store them, and will they keep their quality?

The oils/fat will be getting yellow by next summer, and the buyers will call them "stale". That doesn't necessarily mean there is a problem with them though, if they are kept in cold storage. The auction houses and larger dealers are capable of doing this, however, if you hold them over a year or two, potential buyers might be a little hesitant, not knowing if you stored them properly.
They will still turn yellow in cold storage, nothing you can do about that.

Thanks. As far as hair/fur falling out that would okay? Could you hoop one if not tanned?

Scrape them grease free and dried pelts will keep for a long time in the freezer.
Greasy skins go stale because of the grease left on or in the leather.
Dried greasy skins will go stale in one summer if not kept in a freezer.This yellowing of the skin is called grease burn by tanners,since it will negatively affect the tanning process.
beaver pelts can be scraped grease free by either frost scraping if you live in a subartic climate or by scraping out the liquid grease after boarding conventionally.Cold water applied to the leather side of a stretched beaver skin just before the final scraping on the board breaks up the blood corpuscles in the skin and helps to remove the liquid grease from the skin. A handful of snow does the same thing.
Some fur handlers use a rag dipped in a pail of soapy water to wash down the stretched beaver pelt just before scraping out the liquid grease or in prep for frost scraping.
The best way to keep beaver is to keep the pelts frozen,rolled up in a plastic bag with the air squeezed out.
Board and scrape them a few weeks before your fur pick up or before you ship for sale or to the tanner.

I have several hundred (or more) left that I've had frozen for a decade at least. been shipping them to the dresser with no problem. Let me preface that with my freezer is set at -20 which keeps them in pretty good shape.

If its hooped and untanned its likely to get bugs, and eaten, and hair falling out from the bugs.

Stale beaver that are stored at room temps for a year or two, and the fat goes rancid and turns yellow, will come back from the tannery with hard spots that are brittle and will actually crack and break. Not good.

Storing stretched and dried beaver pelts in cold storage will delay the deterioration of the pelt, which is the cause of the yellowing.

In climate controlled cold storage, such as a fur vault, the yellowing can be delayed for a long time. Even in an ordinary chest freezer, the yellowing can be slowed down for 3 to 5 years.

Just because a pelt, be it beaver or coyote or badger or skunk, has turned yellow does not mean it will not tan up ok. The more yellow, the chances of problems increases. I have had tanned badger and skunk that were almost orange and the bulk of them turned out fine. Yes, there were some pelts that didn’t make it. But over all it was worth the gamble. I’m talking about pelts tanned at a commercial tannery. Not some home tan method using brains and battery acid.

Deducting for pelts that are slightly yellow (slightly stale) is a fur buyers gimmick that has been around for a long time. It has become “accepted” by the trapper. At this point there isn’t much that can be done to change that situation.

I bet these would be good for this...

Thank You all for sharing your experience and expertise advise. I have a couple tanned hooped ones but through the years I just sold and diidn't bother skinning. Time was always my enemy.

Are these pelts ruined? They don't smell and the fur is not falling out..

Never mind I found some pictures and mine look like theirs. I got 3 beaver and they looked really nice and white. Then it got cold last night and they turned color. These are my 1st beaver so I have no idea what they are supposed to look like.

You did great. The fur is still a bit unprime that's why the leather is blue yet. They turn from white to blue as they dry if unprime.

Nice and even, looks pretty good!

The pelt in the pic looks good.
There appears to be a few white spots near the tail where some residual fat is preventing the pelt from drying at the same rate as the clean parts of the pelt.
These fat pockets can be carefully scraped off with a round ended beaver knife and they will dry promptly,or you can leave the pelt on the board until they eventually dry.