Aerating chocolate using mass flow control
Aerated chocolate is increasingly popular because of its particular mouthfeel: bubbles in the chocolate make it lighter, with a unique texture. An aerated chocolate bar has more surface area than a standard chocolate bar, which is why it melts faster in your mouth, intensifying its taste.
How are bubbles added to chocolate?
The short answer: gas injections add bubbles into chocolate. While you can do this in your own kitchen, it involves high-performance mass flow control in commercial settings.
High pressure gas, generally nitrogen or carbon dioxide, is injected into liquid chocolate and forms bubbles. Then, the temperature-adjusted liquid chocolate is moved into molds, where the pressure is reduced and the chocolate is allowed to cool. Since the pressure drops faster than the temperature, the volume of gas increases, resulting in larger bubbles. As the chocolate cools, it solidifies, trapping the bubbles.
Automating aerated chocolate manufacturing with mass flow control
Alicat received an inquiry from a chocolate company looking to improve their flow control for the gas injection into the liquid chocolate. They were using a manual, knob-type control valve, which had proved to be both inaccurate and inflexible.
Alicat’s engineers recommended an MCH-Series mass flow controller, with a high accuracy calibration to maximally improve the process. The MCH-Series utilizes a dual side-by-side valve configuration, known as a hammerhead valve, rather than a standard, single valve design. The combination of the high accuracy calibration and the hammerhead valve ensured the most precise operation – meaning drastically improved quality assurance for the bubble formation process.
At the flow rate required to aerate the chocolate, the MCH-Series mass flow controller has an accuracy of ±0.4% of reading and ±0.2% of full scale, with a maximum inlet pressure of 10 bar (or 145 PSIA), which is sufficient for this aeration process.
This project automated the chocolate manufacturing skid and introduced a smart mass flow controller into the workflow. It included a human-machine interface (HMI), involving a standard interface for operator control on new and upgraded plant equipment and process control systems. In this upgraded configuration, the operator was able to input a flow setpoint using the HMI, which would then automatically operate and control the mass flow controller. Any adjustments required for precision regulation of gas into the aeration tank could also be adjusted easily using the HMI, making tight quality assurance for aerated chocolate easily achievable.