Should wines topped with screwcaps be stored on their sides? What about sparkling wines?

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Dear Dr. Vinny,
Should wines topped with screwcaps be stored on their sides? What about sparkling wines?
—Stan, Auburn, N.Y.
Dear Stan,
As you know, wines topped with cork should be stored on their sides, to ensure that the cork remains in contact with the wine so that it won’t dry out, which can result in premature aging.
Champagnes and most other sparkling wines are sealed with cork, but some experts say that the high pressure inside the bottle eliminates the need to store them on their side. However, we store sparkling wine on its side anyway because that’s how all the other bottles in the cellar are stored, and we think it’s better to be safe than sorry.
Wines topped with screwcaps obviously don’t have corks that are at risk of drying out, so it’s fine to store them upright, but again, the rest of the wines in the cellar are stored on their sides, so we store screwcap-topped wines that way as well.
—Dr. Vinny