It also doesn't affect the fermentation in any way. However, fermented apple juice with ascorbic acid may taste slightly tart. ... But if the product has ascorbic acid, don't worry. It's just vitamin C added to prevent the juice from turning brown.

Is ascorbic acid OK for brewing?

Ascorbic acid is completely fine and is often added to balance the acidity of the juice (see my comments on malic acid below). There are a few things that you can add to your cider that will create a better finished product, but aren't really ingredients.

What preservatives prevent fermentation?

Sodium benzoate is the sodium salt of benzoic acid and is widely used as a food preservative, particularly in acid foods like salad dressings and soft drinks. Sodium benzoate can also be used in winemaking to stop fermentation and prevent spoilage.