u/Beneficial_Advance69

I have a few gallons of blackcurrant wine that has become incredibly tart. Just finished fermenting and i have siphoned into another fermenter to allow to clear. Added stabiliser (sodium metasulphite and potassium sorbate) but due to the tartness i will need to add a significant amount of sugar. How long should i wait to ensure all yeast is dead and added sugar doesn’t ferment?