Overview
Spray drying is one of the most widely used processes in the dairy industry to manufacture milk powders and dried dairy ingredients. As milk is highly perishable, its conversion into powdered form significantly extends its shelf life while retaining its nutritional value.
This advanced food processing technique is integral to modern dairy plant operations and is a core focus area for food processing consultants and dairy engineering experts involved in food factory design.
Spray drying
Spray drying involves the atomization of a dairy liquid—such as milk, whey, or cream-based solutions—into fine droplets using an atomizer. These droplets are rapidly dried with hot air in a controlled environment, producing fine powder with desirable moisture content and stability.
It is commonly used by food technology consulting firms to create:
- Skimmed milk powder (SMP)
- Whole milk powder
- Whey protein concentrate (WPC)
- Infant milk formulas
- Cheese powders
- Caseinate preparations
Products which are manufactured using spray dryer
Varieties of dairy products are manufactured using spray dryer including; Skimmed milk powder (SMP), Whole milk powder, Whey protein powder, Whey protein concentrates (WPC), Milk-based infant foods, cheese powder, powder cream mixes and dried caseinate preparations.
General steps of spray drying:
(a) Concentration
Increase solid content
Reduce the amount of liquid that must be evaporated.
(b) Atomization
(b) Atomization
Inc. SA for optimum evaporation.
To leat to a dried prod. Having desired characteristics.
(c) Droplet air contact
Atomized liquid is brought in contact with the hot air in the drying chamber.
Rsults in evaporation of >95% water.
The way in which spray makes contact with the hot air influences the behavior of droplets in the drying phase and directly affects the properties of the dried product.
(d) Droplet drying
Fine droplets are introduced into a hot air chamber.
Evaporation of over 95% water occurs within seconds.
(e) Separation:
Large particles fall by gravity.
Fines are captured using:
- Cyclone separators
- Electrostatic precipitators
- Filter bags or scrubbers
Single Pass System:
The simplest form.
Atomized droplets are sprayed into hot air.
Dried particles fall into a collection bin.
Basic flow system:
Product is pumped through a feed tank to an atomizer.
Drying gas is introduced simultaneously.
Powder is collected in the base while air is vented out safely.
Let’s discuss different types of Atomizers:-
(a) Rotary atomizer
Uses centrifugal force of high-speed blades.
Produces uniform particle sizes.
(b) Pressure nozzle
Converts pressure energy into kinetic energy.
Ideal for free-flowing powders.
(c) Two fluid or pneumatic nozzle
Combines compressed air with liquid feed.
Used for high-velocity drying.
(d) Ultrasonic atomizer
- Uses vibrating surfaces.
- Produces ultra-fine droplets (<50 microns).
Advantages of the spray drying process:
· Efficient drying process.
· Heat-sensitive and oxidizable materials.
· It can be designed for drying under sterile cond.
· Dried particle has uniform size and shape.
· Good flow property can be easily compressed.
· Used for coating and encapsulation of solids and liquids.
· Labour cost is low, drying in a single operation.
Disadvantages of the spray drying process:
. Solid materials can not be dried.
· Costly and bulky equipment.
· Cleaning is time-consuming.
· Uses lots of heat.
Safety protocols that need to be taken care:
Asphyxiation: Drying gases that are used in the drying process are considered risky, so preventing the factory labor from asphyxiation caused by gases is a must.
Powder contact: This process is considered potent on inhalation and can pose a risk to machine operators.
Explosion control- dust gas and heat are all potential trigger points, prevention is a must for the workers working around the setup.
Conclusion:
Spray drying is a vital technique in the processing and preservation of dairy products, transforming perishable liquids into shelf-stable, nutritious powders. It is an indispensable method for any modern dairy facility looking to scale production efficiently.
By optimizing spray drying through expert food processing consultancy, manufacturers can ensure product quality, regulatory compliance, and market competitiveness.
References:
Back 
PMG stands for Projects Management Group. We provide state-of-the-art Engineering Services to build world-class food processing factories. 
Engineering is the difference between Chaos and Excellence. If you are going to do it, do it right. 
Explore the diverse range of Products in the Food Processing Industry. 
Explore the technologies at the heart of the the Food Processing Industry. 
