Use metabisulfate for preservation and it depends on the PH of the wine as to how much free SO2 you need. What wine are you working with? Has it been thru MLF?
I haven't been making wine for too long but ascorbic acid is reserved for dealing with sulfide stink and is very hard on the wine. Protect your wine with kmeta levels based on pH and limit oxygen exposure and temperature.
Paul
When I make up my sulphite solution, I use 8 tsp Kmeta in 4 litres of water, and add 1/4 tsp ascorbic. It is supposed to help potentiate the solution. The solution is used for rinsing bottles and other equipment, and in the fermentation locks. When I used Kmeta at crush time, I use only Kmeta in powder form.
Ken
I am not an expert but my readings have told me ascorbic acid is hard on the wine, and is used for breaking bonds when H2S issues have gone beyond simple copper treatment.
I am familiar with adding tartaric acid to super strong kmeta solution to use as a santizing/cleaning treatment. I do that to make a barrel storage solution. I'm not sure I would recommend adding any acid in any form to a wine unless taste would be improved...where are you getting your info that adding ascorbic acid will help protect the wine? I'd like to read it.