In my area, cooking wine does not exist. I can only easily find Sherry (for drinking) at 15% alcohol. I was told it should have 20% to be shelf-stable for ~6—24 months.
There is white port at 19½% alc. Not sure if that differs much from sherry in taste, but I suppose 19½% is close enough for shelf-stability.
Should I add table salt to the sherry to make it shelf stable? Or add brandy? Or switch to white port? Or even just brandy?
My main use: less than ~½—¾ shot mixed with corn starch as the thickening basis for stir-fries. I don’t really use sherry for anything else. I don’t even drink it because I so commonly use it in stir-fries that as a straight drink it’s like drinking Kung Pao Chicken because I can’t mentally dissociate it.
I also wonder if I should be looking for dry sherry, or simple sherry. I want the stir-fries to have the sweetness of strong sherry, so I guess dry variants would be contrary to that.
update -- still unclear
Folks are saying ~12—15% is enough for shelf-stability. The non-fortified wines I have are in that range. So I’m baffled because I believe normal wine turns to vinegar if left at room temp after opening.
I also wonder if Sherry is only very slightly fortified since 15% isn’t much more than normal wine.
Cherry tastes different then wine so I wouldn't just replace it. Even more important to your question is: 12% alcohol is enough to be shelf stable. You will get oxidation which matters little if the wine will see a lot of heat anyway. Bacteria hardly attack wine, especially if it contains sulfur like most wines I know.
Glad to hear about the 12% threshold. All the cheap sherry I have easy local access to are 15%.