As we looked at in Part 1, pet foods now come in all sorts of formats, from your common or garden tins and extruded biscuits to the much newer innovations like freeze-dried and complete raw foods. While this enormous variety can seem a bit overwhelming at first, it’s actually great news since, with so many choices available, you can now be more sure than ever that there will be something out there that suits your dog, your lifestyle and your budget.
In this article and the next we’ll compare the different methods that are used to make store bought foods, how they can affect the end product and their pros and cons for both you and your dog.
Dry foods are, by a long way, the most popular category of pet foods globally. They generally offer good value for money and, crucially, they are about as convenient as it gets. There are five main ways of making dry pet foods:
The vast majority of dry dog foods are made by a process called extrusion. Extrusion basically involves the ingredients being ground, mixed and passed though what is essentially a giant steam cooker before being cut into biscuit shapes and dried with currents of hot air. It is quick, consistent, relatively easy and relatively inexpensive so an obvious choice for many manufacturers. It does, however, involve some pretty high temperatures and pressures which may result in the loss of some of the natural nutrients which is why some manufacturers have opted for other production methods.
Like extrusion, baking starts with ground ingredients being mixed into a dough and formed into biscuit shapes. The cooking phase is different though as it typically involves the biscuits passing slowly through a long oven atop a conveyor belt.
Baking allows biscuits to be made using lower pressures than extrusion which may leave more of the natural nutrients intact but it also tends to require the inclusion of wheat gluten to bind the biscuits which might not agree with all dogs.
Cold-pressed complete pet foods are still fairly new on the scene but their popularity is growing fast. Although the pressing process can vary from one manufacturer to another, it generally involves the dry, powdered ingredients being mixed with oils and pressed into a small bite of food before the quick application of heat (usually just a few seconds at 45-70°C) to make the final biscuit.
Cold pressing presents all of the advantages of more conventional dry foods but without the potentially damaging high temperatures.
Ingredients do, however, still have to be dried and ground before pressing and some, like grains, also have to be pre-cooked so cold-pressing still involves a certain level of processing.
Air drying takes things one step further as the ingredients usually start the process fresh rather than ground or pre-cooked. The food is exposed to a current of heated air, gently removing the water through evaporation which is thought to reduce the damage to nutrients compared to conventional cooking methods. Some air dried foods need to be rehydrated by adding water so, while the packs might seem small, the volume of food you get from them is considerably larger.
Freeze dried foods are created by first freezing and then gently heating the ingredients within a vacuum to remove any moisture. In this way, the nutrients undergo very little damage making it arguably the most ‘natural’ form of dry food available. Another pro is that they have an incredible shelf life without the need for any preservatives.
Freeze-dried foods do, however, tend to be eye-wateringly expensive but since many require rehydration with water, the final volume is often a lot more than you might think.
Dry food are great but they are just the tip of the iceberg! Make sure you take a look at Part 3 where we’ll be taking a look at all the alternatives including wet, fresh and, of course, raw foods!
Author: David Jackson, All About Dog Food