Dogs love dry food. It’s formulated for crunch, and coated in flavors meant to tempt your dog into licking its bowl clean. If that’s just what your dog is doing, you don’t need to add anything to its bowl to spruce it up — unless you want to add some supplements or healthy veggies.

In the article “The Chemistry of Kibble” by Mary Roach on Popular Science, the author describes her visit to AFB International, a company that makes liquid or powdered palatant coatings designed to make kibble taste delicious. Palatant can include proteins, yeast and antioxidants. Roach’s article notes that the main ingredients in AFB’s dog food palatants are liver mixed with other viscera.

“AFB designs powdered flavor coatings for the edible extruded shapes,” Roach writes. She explains that kibble on its own doesn’t have much taste. “The flavor comes almost entire from the sauce—by design.”

This enables pet food companies to produce one type of kibble and coat it in a variety of flavors, ready for retail. Kibble is designed to appeal to dogs and gets taste tested by hundreds of dogs at facilities like AFB International before it hits store shelves.

So, what gives? Why do some dogs refuse kibble? Is it the dog, or are owners looking for ways to get their dog more diverse nutrients when they decide to improve on kibble?

Either way, it’s easy to add some pizazz to kibble and make it more appealing.