What is crude ash in dog food?

Health and Wellbeing

Ash in dog food is not the kind of ash you’d find after a fire but rather relates to the number of minerals that are in the dog food. It’s described this way as when the food is incinerated at very high temperatures the only thing that’s left is the minerals. These are things like calcium, iron, magnesium, potassium, zinc and other minerals like these that dogs need in their diets to grow and be healthy.


Dog food cannot be produced without ‘ash’ and when testing dog food scientists will use a bomb calorimeter to burn the food. This will then allow them to work out what the energy density or Kcal/100g the food is, as well as how much protein, fibre and fats are in the food. After this process, they’re left with the mineral content of the diet, or ash. And of course, this is only for testing purposes and the actual food you buy won’t be burnt or include ash in it.


Usually, dry dog foods have between 5 and 8 per cent ash and wet foods have between 1 and 2 per cent. Percentages have even gone up to the 10 per cent levels in some dog foods. Higher quality meat will have lower levels of ash because it will contain less bone than other meats. These levels could also vary depending on the type of meat with chicken and fish having lower ash content naturally whereas red meats have a higher ash content.

Lower ash content is typically better as it means the meat that’s used in the food is of higher quality and there are fewer filler ingredients. What is more important though, is knowing how much of each mineral is in your dog food and how these minerals can affect your dog.


Ash in dog food is safe and good for your dog as it means there are minerals in the dog food you’re feeding (not actual ash from a fire), that are good for your dog’s health and growth. But you should be wary of food with percentages above 8% as this generally means the meat is of lower quality and there are more filler ingredients in the food. Many large corporate dog food companies don’t disclose how much ash is in their recipes so it can be hard to understand whether the food you’re feeding is good quality or not.

Dr Andrew Miller BVSc MRCVS

Written by: Dr Andrew Miller MRCVS

Andy graduated from Bristol University in 2010 and sees nutrition as a foundation for our pet's wellbeing and takes a common-sense approach. We are what we eat, and it shouldn't be any different for our pets.