A winemaker in the USA can add any of these acidity adjusters to their wine without disclosing the info to the consumer.

calcium carbonate
malic acid
tartaric acid
lactic acid
potassium bicarbonate
sodium bicarbonate
potassium hydroxide
sodium hydroxide
ammonium carbonate
ammonium chloride
ammonium hydroxide
magnesium carbonate
sodium carbonate

The only way to know what is in your wine is to ask the winemaker directly.
Shake your Winemaker's Hand