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What if you could tweak the recipe on ice cream to keep it frozen at higher temperatures? The idea comes from massive conglomerate Unilever. Among other things, the brand owns a wide variety of ice cream brands, from Ben & Jerry’s to the Magnum and Cornetto lines. Instead of running freezers at the industry standard of -18 °C (0°F), the company is experimenting with upping the temperature to -12 °C (10 °F) instead.
First off, you’d save a lot of electricity. Thanks to the way the industry works, the company actually owns the vast majority of the three million or so display freezers that are used to sell its stock to customers. Running at a higher temperature could slash the freezer’s energy use by 20% to 30%, according to the company’s calculations. The company also estimates that the energy used by these freezers makes up around 10% of its total greenhouse gas footprint, so it’s better for the environment too.
Of course, there’s savvy commercial reasons behind the idea. Unilever had noticed its ice cream sales dropping in 2022. The company believes this was in part due to retailers unplugging their freezers earlier than usual as winter approached, due to high energy bills. If the company’s freezers aren’t humming, they’re doing less business. If shaving down the freezer’s energy use helps retailers keep them plugged in and the lights on, that’s a net bonus to the company’s bottom line. It could also make their freezers unhospitable places for rival products, giving them an edge in the marketplace.
But this is all business intrigue. Let’s instead take a deeper look at ice cream.
Oh, Sugar, Sugar
If you know anything about ice cream, you’ll know that this idea is fraught with challenges. Conventional ice cream starts to get soft and liquid around -14 °C (6.8 °F). Warm pre-packaged ice creams are no fun. They tend to fall apart, slide off their sticks, or just generally form a gooey mess in the wrapper.
Thus, Unilever couldn’t just change the set point on its freezers and call the job done. Instead, it has had to modify its products to stay frozen, solid, and stable at higher temperatures. It’s a food technology and a chemical engineering challenge. The company wishes to save energy without compromising on the taste, quality, and mouthfeel of its products.
From a structural perspective, ice cream is made up of air cells, ice crystals, and fat globules. The relative compositions of these components and the ice cream as a whole influences the melting temperature and the rate. Current publicly available research shows that ice cream with high air content tends to melt slower, a useful attribute for ice cream that is served closer to room temperature. As per a paper from Goff & Hartel (2013), smaller air cells are also correlated with a slower melt rate. However, the very techniques that create smaller air cells can also create larger ice crystals, which have a negative effect on texture on mouthfeel. Meanwhile, higher fat content can slow melt rates, but can affect the flavor profile of the ice cream.
At the industrial level, playing around with ice crystal size and fat content is mere child’s play, the mainstay of the undergraduates in Ice Cream Fabrication 101. Cutting-edge food technologists have far fancier tools to play with, from advanced binding agents to useful emulsifiers like polysorbate 80 or diglycerides. These components can do all manner of wonderful things to a food’s structure. They play a serious role in finessing a product for the ultimate customer satisfaction and ease of manufacturability.
Thus far, Unilever is tight-lipped on the cost of this exercise, and the manner in which it achieved its goal of developing so-called near-room-temperature ice cream technology. It cites recent developments concerning sugar as key to its success. It bears noting that Junior and Lannes (2011) found that choosing different sweeteners could drastically alter an ice cream’s freezing point. If you’re working at Nestle, and the bosses upstairs have just yelled at you to figure out how to make warmer ice creams, it might be worth starting there.
Melting Like An Ice Cream
The company has managed to bankroll the effort as part of its usual expenditure on ice cream research and development (ICR&D, in industry parlance). According to the company’s head of ICR&D, Andrew Sztehlo, the effort has been a decade in the making, with the full project expected to take 15 years in total.
Initial pilots were pursued in Germany, where Unilever aimed to discover which of its products could live at -12 °C (10 °F) without reformulation. The next stage will take place in Indonesia, where reformulated lines will be put through rigorous testing. This will involve blind taste tests to ensure quality isn’t compromised, as well as investigation around melting behavior and sensory responses to the new ice cream.
The company hasn’t yet committed to warming up the majority of its freezers just yet. If it does, it could give the company a surprise competitive advantage. Many shop owners will use freezers provided by Unilever to also stock goods from the company’s competitors. If those items aren’t designed to live at the new higher temperature, they could suffer in quality, pushing customers towards Unilever’s reengineered lines. Speaking to the Wall Street Journal, Sztehlo says the company plans to share its findings with competitors in the event it succeeds in its quest. That’s easy to say in a press release, but something an astute adult might expect Unilever executives to balk at.
If the project goes ahead with a public rollout, expect Unilever to remain quiet on the reformulation angle. Instead, it will have to find a way to thread the needle: simultaneously espousing its green values to customers while avoiding the negative perception of warmer ice creams. It’s an interesting path to take, given that much of the energy savings will be enjoyed by individual shop owners, rather than Unilever itself. Regardless, if the gambit works, expect rivals to rush to match the company’s work. If not, expect your local store’s freezer to stay locked at a cold and frosty -18 °C (0 °F).