Spray drying is the process of converting a mixture in its liquid form to a powder. This is done by removing the moisture component from the liquid solution. The solution, sometimes called an emulsion, is sprayed through a nozzle into a chamber that simultaneously has hot air being blown into it. As droplets of the solution are released through the nozzle and come in contact with the hot air, the moisture content of each droplet is removed, thus turning it from liquid to powder form.
 
To offer a real life example of why one might have a need for spray drying, let’s look at milk. In many parts of the world, refrigeration is not as “mainstream” as it is in regions such as North America or Europe. The ability to keep cold large quantities of a product like milk is limited. In these regions, powdered milk is used because it can be made on an as-needed basis, thus increasing its shelf life.
 
Additionally, because the availability of liquid milk might be limited, it often needs to be shipped in from another location. Because milk is 80-90% water, by spray drying it, one can effectively reduce its bulk weight. Spray drying 100kg of milk could potentially reduce that weight to 12kg, which offers huge savings in shipping costs.
 
Including fat-soluble vitamins in a powdered nutrient premix is done by first spray drying these nutrients and then adding them appropriately to the premix. Spray dryers provide a quick method for drying a product compared to other available methods. Thus, a crucial advantage of spray drying is that a mixture can be turned into a dried powder in a single step resulting in not only profit maximization but also process simplification.