What's tooth enamel erosion from?

From acids : Enamel erosion is from acids in the mouth. These acids can be from foods and beverages ( such as sodas, lemons, candies) or from the intestinal system ( such as acid reflux).

Grinding, bruxism: Sometimes grinding and clenching your teeth may cause erosion, stomach reflux and regurgitation will cause it, certain foods, like citrus in excessive amounts.

Acids: The most frequent cause of tooth erosion is acids in your diet. Acidic foods, citrus, soda, even diet, energy drinks, juice drinks, iced teas, etc. All are highly acidic.