There are basically three categories of dog food – canned, kibble or raw — but there various sub-categories and distinctions within the categories. The healthiest category of food is “raw” but is also the category that gives most pet owners pause. Beyond uncooked raw food — fresh meat, vegetables, fruits, etc. — there are the “freeze dried”, “dehydrated” and “air dried” varieties.
Typically, a dehydrated dog food is one that has had the moisture removed from it through a process of low heat for a long period. The raw meat and other raw ingredients are prepared then subjected to warm air, under 200 degrees, that is circulated over and around the food. The food is not cooked and retains most of its nutritional value and enzymatic properties. Dehydrated food falls into the raw category because dehydrated food’s nutritional value is extremely close to that of raw and because the dehydration process does not cook the food. The Honest Kitchen is a great example of a wholesome dehydrated pet food.
Since freeze dried food has not been subjected to temperatures above freezing while it was being processed, it is almost nutritionally identical to its uncooked counterpart, except with no water in it. Essentially freeze drying, in terms of pet food, is removing the liquid from the food, while keeping it frozen, thus never moving the food beyond its raw (uncooked) state. Through a process of super low temperature and low pressure, the liquid in the raw food is phased directly from a solid (frozen) to a gas (water vapor), thus removing the moisture from inside the food and bypassing the liquid state all together. Stella and Chewy’s is a high quality freeze dried dog food.
Air dried pet food has had the moisture removed from it via evaporation. It essentially IS dehydration, but heat is not always used. Many raw pet food companies are using air drying, or a patented form of air drying, to preserve the nutritional value of meats while maintaining it’s “rawness”. ZiwiPeak is a quality air dried food.