First of all, it seems essential to specify that a vanilla bean, harvested at maturity, prepared and refined in the rules of the art does not require particular conditions of storage (like rum or alcohol) apart from an adapted container.
The Glass Tube or Jar
In addition to the advantage of a more careful presentation, it allows better conservation of the vanilla . The latter left in the open air having the disadvantage of drying very quickly.
To avoid, the cork, it is natural, but it promotes the development of mold .
It is essential to adapt the contents to the container, i.e. the least possible air to avoid accelerated drying of the pods.
The plastic sleeve
Practical, but not very airtight, it can have the disadvantage of letting the aromas through and drying out the vanilla .
To be reserved for regular consumers. Always adapt the content to the container as for the glass (little air).
Storage in the refrigerator
Vanilla pods have the disadvantage of acting like a sponge by soaking up the aromas of other foods, moreover the cold will dehydrate and dry out the pods.
The interest of such conservation is therefore really nil.
Clearly not recommended!
It is always surprising to see vanilla sellers, mainly on the web, advocating this alternative method of preservation, certainly modern, but not very suitable for vanilla.
Would it be possible to freeze a noble product which in essence does not denature?
More prosaically, to decide on this debate, it suffices to say that freezing did not exist at the time of the Aztecs and that it is not applied either by the producing countries, which are in great difficulty to already have systems of conventional refrigeration.
Remember that freezing neutralizes & blocks the natural development of aromas (a pod continues to mature over time).
Ex: frost, this does not express itself at best before 12 months under optimal storage conditions. As soon as your pods are frozen, no frost can be expressed. Remember that the developed frost is pure vanillin.
The only interest for a salesman not very sure of the quality of his products is indeed to advise you to freeze and to apply the precautionary principle, by stopping the possible development of moulds for badly refined pods.
The alcohol background
Same as for freezing, the interest is zero except to want to prevent bacterial development on pods that are too wet or poorly ripened.
Remember that alcohol acts as an aroma extractor, this is perhaps the only interest in obtaining a vanilla rum for example.
The acceptable alternative - Sugar
You will certainly obtain a vanilla sugar but this will automatically dry out your vanilla bean, it will not be unfit for consumption but will have lost some of its aromatic power.