The Art of Ice Cream Engineering
How the Babcock Dairy Plant achieves dairy manufacturing education and outreach
By Steve Wishau Photos by Alex Steinhauer Print Design by Austin Kaiser
Built in 1951, the Babcock Hall Dairy Plant and Store is the oldest university dairy building in the United States, maintaining a long and rich tradition throughout its history. By producing signature dairy products, the operation of the plant helps support the UW-Madison food science department mission of dairy research, education and outreach into the community and industry.
Within the realm of Babcock Hall, there are three separate entities: the department of food science, the Center for Dairy Research and the famous Dairy Plant and Dairy Store, whose operation is stewarded by the food science department. Each group within the building has slightly different goals to achieve on a day to day basis, but there are numerous overlaps for the benefit of all parties involved. Professor Scott Rankin, the chair of the food science department, oversees the interactions between each entity. “The facilities give our students an intimate exposure into dairy foods manufacturing,” says Rankin. “Dairy is a $26.7 billion dollar industry just in Wisconsin. It is critical for food science students that come from Wisconsin to learn about dairy foods manufacturing.”
In addition to educating university students, Babcock Hall has the necessary accommodations for welcoming community members. “We even have parking spots outside Babcock Hall for buses, because all year round, we accommodate tours for preschool classes to retirement homes who can come in and have an ice cream cone or go upstairs to the overlook and gallery to see what a dairy manufacturing plant looks like,” says Rankin. “It’s valuable exposure to the public to see how complex it really is.” Based on trending community or seasonal topics, the plant can make specialty ice cream. Berry Alvarez was introduced when the head coach of similar name was with the football team and continued in production to follow his stint as athletic director. Products that include pumpkin flavors for Thanksgiving or candy cane flavors for Christmas are only a few of countless examples.
One of the advantages of working as a researcher within the department is that one can go right from an applied science approach in a lab setting to manufacturing the product in the plant. “For instance, let’s say I want to work on sensory performance on a new ice cream through a new ingredient that can provide a new functionality to the frozen dessert,” says Rankin. “I can figure out the chemistry of the product in the lab and then go into the plant to actually make some of it. I can then demonstrate to industry that yes, the product works, and give either drawbacks or new efficiencies.”
This produces a legally licensed product as opposed to academic research in a lab. Without the dairy plant, the food science program would be somewhat limited. Because the plant can make a product and describe how it works in a real setting, evidence is supplied to the patent process to verify a new or novel way of doing something. Professor Rich Hartel, a professor within the food science department who has worked in ice cream research for over twenty years, is involved in a new frozen dessert center startup within Babcock Hall. “There are several people within the department that work on ice cream. They do outside services for companies that want to manufacture ice cream,” says Hartel. “In my lab, we do ice cream structures analysis and do service for industry, as we are one of the few places that can measure ice crystals and air cells in ice cream.” Companies are able to send in samples to be analyzed that are sent back after completion. For sensory and flavor applications, companies can send in samples to Professor Rankin’s lab. In addition to the facilities within Babcock, an industrial refrigeration consortium facility is located within engineering. Essentially, the areas of manufacturing, structures analysis, sensory analysis and industrial refrigeration have come together to form one center where companies can come together.
“We already have the facilities needed for the center project,” says Hartel. “We have an ice cream lab with six to eight different smaller scale ice cream makers. We have the dairy plant, a large scale facility that we’re looking to renovate to purchase another freezer for more time and resource availability. In my lab, we have structural analysis equipment and sensory panels.” There is an upgraded freezer that is used in pre-aeration and recirculation of ice cream which can give unique characteristics to ice cream. Everything is in place, Babcock Hall just needs to communicate to companies that the center is open for business and that all functions are available for use.
The main focus of research with ice cream has changed from ice crystals to air cells within the mix and now concentrates on fat globules within ice cream. The fat globules start as individual droplets in the ice cream, mix and arrange until they become clusters in the finished product. The clusters lock the air bubbles and help stabilize the air bubbles content and change how the ice cream melts. “Some ice creams melt quickly or drip fast and others drip much more slowly or not at all. This is related to the nature of the fat globules on how they coalesce and cluster,” says Hartel. “Most products are tested through the standard drip through test. A chunk of ice cream is placed on a screen and we watch it drip. Sometimes it flows right through or it remains solid on top, again depending on the clusters.”
Fat globules are the forefront research topic within ice cream, but some companies are interested in adding or subtracting ingredients depending on the final goal. There has been developmental research done on adding more protein to ice cream to measure nutritional and freezing effects content. A popular idea within the industry is replacing sugar or fat within the product. “Companies want to use stevia, an alternative sweetener designed to replace sucrose. It is a high intensity sweetener, which allows a fair amount of sucrose to be removed and replaces it with only a small portion of stevia,” says Hartel. “However, one of the key attributes of ice cream is the freezing point. If the sucrose is removed, the freezing point changes.” It is important to achieve a freezing point of the mix, but even more importantly, as the ice cream freezes, the freezing point changes to a freezing concentration. It must be correct or, after freezer insertion, the product will turn into a block of ice. Overall, it will be a challenge to replace sugar with stevia to get the sweetness but still achieve the same freezing point. “Ice cream is a pretty complicated material. It is important to understand the idea that changing one thing will change a multitude of things, which can impact the final finished product.”
The overall quality of ice cream depends on the fat content. The store brands hover around 10 percent, the lowest amount to still classify the product as ice cream, and the higher quality more expensive brands are at 16 percent. A technique is used by the industry to remove the fat content and still achieve the same quality. “A really cool example of this is found in Edy’s slow churned ice cream. The idea is that you can make the ice crystals smaller to create a creamier texture that can offset the reduction of fat content,” says Hartel. “Five years ago, you could go to the grocery store and the regular 12 percent content dominated. Nowadays, there is significantly more slow-churned product and only a small portion of the regular.” This process of slow churning involves dynamic freezing followed by packaging and placement into a hardening room for static freezing. This represents the most recent breakthrough in ice cream. “This process was developed in the 90s, but it really has picked up steam within the last five years,” says Hartel. “It’s not inexpensive, roughly the price of a new freezer, but it’s commercially available and reduces the fat content.”
To educate companies on this ice cream manufacturing, Babcock offers courses geared towards educating industry members on dairy manufacturing. “I teach a course on ice cream manufacturing about what it looks like, the chemistry of the product and manufacturing in the plant,” says Rankin. “For the class, we’ll make about 300-400 gallons of ice cream. If an engineering student goes off to work at a company like Ben & Jerry’s, it might not be a bad idea to come back and learn about ice cream science.” Some companies may be able to manufacture the product but they are unsure as to the hard science behind what’s actually going on with the formulation. Having a good understanding of mass balance and heat transfer is helpful, but companies can send their employees to learn about the chemistry and structure specifics. At its core, the Babcock Dairy Plant can educate both university students and members of industry about ice cream engineering.