What is the difference between wet and dry food?
Pet food comes in many different shapes, sizes and textures these days. Food technology has become very sophisticated and allows your pet to enjoy a huge variety in the food that it eats. But it can sometimes be confusing when deciding whether to feed wet or dry food. The differences are explained here:
Dry food looks like a biscuit or kibble and comes in bags of varying sizes. It does contain water, usually up to about 11%, which is added into the mix of ingredients to make a dough, rather like bread-making. The dough will rise in the cooker and then is pushed through a small hole or die, under pressure. This process causes the dough to heat up, and it is cooked as it is pushed through. A cutter then cuts the cooked dough coming through into kibbles. The die can have holes of different shapes and sizes which is what gives the kibble its appearance. Some kibbles are simply round in shape whilst others might be fish shaped, heart or cubed depending on the manufacturer’s preferences.
If you look at the ingredients list on a packet of dry food, many of the names will be similar to those found on a wet or canned food, but with a few differences. Dry food has more carbohydrate in it and this will usually be provided by cereals such as wheat, corn (or maize) or barley. Often they will appear as the first ingredient on a dry pet food packet, meaning that this is the ingredient which weighs the most. In a dry food, carbohydrate helps to hold the kibble together (again it’s likened to bread or biscuits) and gives it structure and texture. While a cat or dog doesn’t strictly need carbohydrate in their diet, it brings an economical readily available energy supply to the food and is a source of other nutrients such as important amino acids (building blocks of proteins) and fibre.
Dry food will still contain other ingredients such as meat meal and fats, though these ingredients are ground and mixed together, so you won’t see pieces of meat in the food. Again these ingredients are providing energy to the diet, along with protein to help with muscle, skin and coat maintenance and other processes in the body. Protein can sometimes be provided to the diet through vegetable ingredients such as soybean.
Complete and complementary
Dry foods can be complete or complementary. A complete food is one which provides all the nutrients your pet will need. A complementary food needs to be fed alongside something else –for example a mixer biscuit, which needs to be fed alongside some wet food. You can check on your pet food packet whether it’s complete or complementary. If you’re only feeding dry food, then it should be complete.
It is also very important to make sure your pet has plenty of fresh water available when fed dry food, as they will not get the moisture from their food that they normally would.
The other major difference you will see with a dry food is the addition of preservatives or antioxidants. Because a bag of food is typically opened and used for much longer than a can of wet food, the fats in the diet are exposed to the air for much longer and may go rancid, affecting the quality and taste of the food. So preservatives have to be added to slow down this process of oxidation. You won’t see them on the ingredient list for tinned wet foods, as these are typically stored in the fridge once opened and used up within a few days.
Tip: Feeding dry food is very convenient and allows a greater number of days feeding to be stored. Just check that you buy the right sized bag for your pet so that it will not stay opened for months and months before you use it up. Once opened the contents will be exposed to the air and will deteriorate if left a long time.
Tip: If you buy a big bag of food for your pet, consider decanting some of the kibbles into a smaller container, and top this up when needed, so you don’t have to open the big bag so frequently. This will help keep the contents fresher for longer.
These will often take the form of soft moist kibbles and have a water content of around 35%. To help hold in the moisture often humectants are used. They also tend to be higher in sugars to help inhibit growth of bacteria. For this reason they are not suitable for diabetic animals that have a poorer ability to control their sugar levels.
These contain between 70 and 85% water, mixed in with the ‘dry’ ingredients. This means that the product, whether in a can, a pouch or tray, will weigh much more than the equivalent dry food. Transporting and shipping wet products is therefore much more costly than dry and this is part of the reason why feeding tins is a more expensive way to feed your pet.
Tip: Many pet foods come in both wet and dry versions, and it’s cheaper to feed the dry version. Just make sure you always have fresh water available for your pet to drink.
There are some other differences between the ingredients used in a wet and a dry food. Wet food often contains higher amounts of protein and fat than dry food and this is why it is often perceived as tastier by the pet. Ingredients such as meat, meat meal or animals derivatives will appear higher on the label. These protein and fat sources are providing energy and components for the metabolism, as well as building blocks for muscles, skin and hair. Often there is very little or no cereal in a wet food, although there can still be carbohydrate provided in any vegetable ingredient.
Though high in water, you won’t find it swishing around in the can. This is because the water is trapped by other ingredients such as gelatine or some sugars which hold it in place and form a jelly which helps to evenly distribute the food chunks or suspend them.
Wet foods don’t tend to have preservatives as they are intended to be used up too soon to allow them to become rancid. An opened can should be stored in the fridge and used up within a few days.
Dry food or wet food ? – some tips to help you choose
Dry food is less expensive to feed. If you want to reap the benefits of feeding a premium food, then feeding the dry version is a more economical way to do it.
Dry food is more convenient to feed as you can buy a larger quantity in one go and takes less room to store than feeding wet food for the same number of days.
If your pet likes to graze throughout the day rather than eating their meal in one go, dry food is more appropriate to leave out.
If your pet is a fussy eater, then a wet food might be more appealing and encourage eating. You can also warm a wet food gently to body temperature which increases its aromas further.
Dry food can have some benefit in helping to keep teeth cleaner as the kibbles can have an abrasive action. Some, such as Hill’s Science Plan Oral Care, is specially designed to work even harder by wiping the teeth clean when the animal bites into the kibble.
For older pets, a moist or semi-moist food can be easier to feed if they have dental problems.
Cats aren’t great at drinking water. For cats prone to urinary problems, feeding a wet food can help them to take in more water and so help them to urinate more often.
Many people choose to feed both, for example, giving dry food in the morning and leaving it out during the day, then giving a wet food meal at night.