Class IV Caramel Colours, identified as E150d, are commonly known as ‘Ammonia Sulphite Process Caramels’ or ‘Acid Proof Caramels.’ These E150d caramel colours are dense, dark black-brown, and thick viscous liquids produced through controlled sugar cooking, featuring a significant negative colloidal charge.

They are crafted using food-grade acids, bases, ammonium, and sulphite compounds, resulting in a colour range from light brown to dark black-brown, lending a brownish hue to the final product.

Class IV (E150d) caramel colours excel in applications requiring strong acid stability and are commonly used in soft drink concentrates. Alvin, a leading manufacturer, offers them in Single and Double Strength versions, with Regular, Premium, and Supreme grades, each featuring multiple variants to suit diverse application needs.