Al,
I would agree that temperature is way more important than orientation. Interestingly, the CIVC did use temperature as a variable in their study of bottle storage orientation and they found bottles to show better (based on taste) when they were stored upright without regard to temperature. IIRC, the greatest differences between horizontal and upright storage were shown in high temperature storage.
Eric,
Space constraints are the main reason you won’t see a winery store upright - it isn’t an efficient use of most spaces. What you will see is plenty of upright and upside down storage of bottles in the treasure cellars of older bottles where space isn’t at a premium.
I will also add that I don’t think studies have been done on orientation of bottles still under crown cap. If you were to do one I am not sure the same theoretical advantages would exist - possibility of cork failure/weakness and cork taint (regardless of whether or not these turn into real world, actual occurrences).
I once read some theoretical reason why standing the bottles upright is better–it that it had something to do with the flared cork (unique to champagne corks) and the way the Champagne cork seal works. I think the idea is that a normal cork can become soft, weak, soggy, crumbly, etc., over time (requiring an “ah so” to remove the cork without crumbling/breaking apart), without causing any real issue for wine storage…whereas the flared cork requires that the cork material itself maintain some strength, since it always has significant pressure against the cork. So the claim is that a “dry” cork is better in this case–almost exactly the opposite of a regular cork, where a cork could become too dry, leading to seal failure.
However, this seems pretty far fetched (a concern that would be rare to come into play) compared to the immediate demands of practical storage. Upright storage is incredibly inefficient…
No producer does this for the practical reason of space…science has shown that upright is indeed the very best way to store sparking wine… How much better is it??? only us nerds would be able to tell in the most negligible way the difference … My knowledge of this is a priori one via science, not practice … For disclosure… Being a science man the other arguments are moot …
Cheers !!!