What do you recommend for storage of screw-capped bottles? Should they be stored horizontally or are they better stood up to keep the wine and plastic separate? Is there a guideline for how long they should be stored either way?
There's no advantage to storing them horizontally - as you should do with bottles sealed under cork. I would recommend storing them vertically, for a couple of reasons. Many fine wines designed for cellaring are now sealed with screw caps. The point is to avoid the modern scourge of cork taint, a foul-smelling defect caused by a fungus that randomly attacks cork bark.
Wines sealed with cork, if they're going to be cellared for an extended time, must be placed in a horizontal position to keep the cork moist so that it maintains a tight seal against the bottle neck. That's not the case with screw caps, which contain a synthetic liner that grips tightly around the rim of the bottle. Synthetic liners don't need moisture to maintain their seal.
One reason I like to store screw-cap bottles upright is to save precious bin space in my cellar. I even have some standing on the floor. The other reason is that the jury is still out on whether synthetic liners, over the course of decades, will impact the flavour of the wine. But I don't want to sound alarmist; it's probably not an issue to lose sleep over. Today's screw-cap liners generally are made of highly inert, medical-grade synthetics, similar to the plastic used for hospital intravenous drip bags.
The other good reason to store screw-cap wines upright has to do with serving convenience. After many years in the cellar, fine wines, which tend to be only lightly filtered if filtered at all, will throw a deposit. Horizontal bottles should be turned upright roughly eight hours before they're uncorked (24 hours is better). This will ensure that the sandy deposit sinks to the bottom. If the screw-cap wines are stored upright in the first place, there's no wait time.
Have a wine question?
E-mail your wine and spirits questions to Beppi Crosariol. Look for answers to select questions to appear in the Decanter newsletter and on The Globe and Mail web site.