Well, the good news is they
don’t. If you’ve read or been told that dog food manufacturers use actual ash as a cheap filler, ignore it. It’s a lie — one of those internet horror stories. (Please don’t write in telling me it’s not, because it is.)
For the truth, please read this article that we’ve recently expanded and updated (because some people were still confused): Why Is There Ash
in Your Dog’s Food?
In short, ash is a measure of the nutrients left if you were to completely incinerate a dog food (which would be a weird thing to do at
home). The protein, fat and carbohydrates would burn away, leaving just the minerals behind, such as the calcium from bones. This is the ash.
It’s a useful measure, but a
terrible name.
I encourage you to read the article and absorb all those lovely facts. You’ll find them very useful when speaking with someone who believes the horror stories.