Some priests are in recovery from alcoholism, and may have permission to consecrate with mustum (which is not quite Welch’s, but close).
It might be better described for the circumstances as, “wine of very minimal fermentation which, left to itself, would continue to ferment.” (Even that I’ not sure of, as I think [but am not sure] that the yeast can filtered out and still use it in the liturgy. Note that yeast naturally occurs on grapes, of the correct type, although all but a small handful of modern vintners add yeast to accelerate active fermentation.)
A couple of years ago, err, many years ago, I thought that the cup I was holding as a Eucharistic Minister at my Jesuit college smelled strongly of grape juice.
After communion, the priest explained that if you’d encountered that particular cup, there was a reason. Part of the treatment he’d received involved giving the subject alternating glasses of their favorite drink and warm salt water to drink–conditioning the priest to vomit on smelling his preferred poison . . . and the further comment that this was a really bad idea at the altar
Note that this was in the '80s, before the rules were settled. Also, I doubt that the salt water thing was actually a good idea therapeutically, but what do I know?
As a side note, I used to get an occasional glass of canned zinfandel grape juice from my grandmother (after the winery folks paid & picked from their vineyard, she’d go in a couple of weeks later an pick the late ripening ones). You would
never mistake that kind of “big red” for Welches . . . it would actually etch the mason jar! (and once my grapes out back produce enough, some will get held back from winemaking for juice production).
And while on Welches . . . my baptist Protestant Theology professor was raised in one of the “unfermented wine” Baptist groups. He said he got in trouble growing up for not understanding why Jesus got flack for “too much Welches”
AMDG
hawk