What are the ingredients for red wine?

Red grapes, sugar, water, and mother yeast.

When put together, the juice of the grapes ferment and form wine (or vinegar eventually). The first three ingredients are well known, the last not so much. Mother yeast is a living yeast culture that every vineyard keeps on hand. It is closely guarded and cared for. Each batch or vintage of wine produced receives a small portion of the mother. This is what begins the fermentation process and ensures consistency of product.
It depends on the type of red wine. Some are blends of different grapes to give a certain taste while others are one type of grape. The principal ingredient in wine is the juice from the grapes that are used.