How do you get the perfect ice cream with flow controllers?

For most people the classic summer treat is ice cream. Around 7 billion gallons of ice cream and other related frozen desserts are produced every year worldwide, with production peaking (as you might expect) in the summer months, according to the International Dairy Foods Association. Yet, the moment you consume an ice cream, you will probably not wonder how this delicacy is being made. To get that perfect ice cream, a mass flow controller is often used.

What does ice cream have to do with mass flow meters?

Ice cream contains many different ingredients, such as fat, sugar, milk solids, an emulsifying agent, flavouring and sometimes colouring agents. But there is one main ingredient that you may not have thought about, probably because you can’t see it—air. Ice cream is made by freezing and simultaneously blending air into the ingredients. So why is air so important?

If you have ever had a bowl of ice cream melt, and then refroze it and tried to eat it later, it probably did not taste very good. Moreover, if you leave a carton of ice cream out in the hot sun and let it melt, the volume of the ice cream would simply go down. Air makes up anywhere from 30% to 50% of the total volume of ice cream, therefore, aeration in the production process is crucial.

Possible flow scheme of whipping ice cream process

The amount of air in ice cream (often called overrun) affects the taste, texture and appearance of the finished product. Higher aeration will produce a tastier and smoother ice cream. A side effect of adding air to ice cream is that it tends to melt more quickly . Thus, for attaining an optimal structure of the ice cream, it is important to have a stable inlet air flow in the production process with a constant cream/air ratio. This can be achieved by using a mass flow controller.

To get an idea of the effect of air on ice cream, think of whipped cream. Whipped cream - cream with air - has a different texture and taste than plain cream. To learn more about this process, please read the story of our guest blogger Hans-Georg Frenzel, from Hansa Mixer, where he explains how air is used to create whipped cream.

Figure 1: Ice cream microstructure

The process of whipping ice cream into shape

To guarantee the right consistency and structure which ensures a full flavoured ice cream, the cream must contain the correct proportion and composition of air bubbles. Hence, aeration mixer manufacturers use a mass flow controller to dose an exact amount of air into the cooled mixer. Such a mass flow controller will ensure a continuous air delivery, proportional to the cream flow . The mass flow controller must be capable of maintaining its performance regardless of any possible back pressure variation. Occasionally, a check valve is mounted at the mass flow controller’s downstream. If inlet pressure drops, such valve will avoid ice back stream into the instrument. A pressure meter is also used with the purpose of monitoring the inlet pressure.

Bronkhorst EL-FLOW Select flow meter

The SEM (Scanning Electron Microscope) picture (figure 1) shows the ice cream microstructure. Air bubbles are a critical ingredient. Experts claim its optimal size, distribution and quantity are one of the secrets for having a creamy texture recipe. Hence, according to meet such demands, Bronkhorst has provided efficient solutions for enhancing continuous aeration processes.

So, the next time you head to the ice cream parlor with your friends, be sure to keep in mind the importance of Bronkhorst when it comes to that delicious refreshment.