Keep cool this summer and get the scoop on NH3 in ice cream production

As the summer heats up many of us will indulge ourselves with an ice cream. To ensure impeccable temperature control, essential in the manufacture of this summer treat, ice cream plant operators need a refrigerant that can reduce energy consumption, save money and helps them adapt to restrictions on the use of HCFC-22. Ammonia, which meets all these criteria, is often selected as the preferred refrigerant.

We have come a long way since one of the first recorded versions of ice cream, a snow, grapefruit-concentrate-covered creation produced by the Persians around 400BC. Ice cream’s worldwide popularity today, is largely thanks to the advent of refrigeration and in particular the continuous-process freezer, perfected in 1926.

Ammonia-cooled barrel freezers key component in ice cream making process

In the process of making ice cream one of the penultimate steps involves pumping the pasteurised, homogenised and aged ice cream mix into a metal barrel, surrounded by a very cold refrigerant, often ammonia. Such barrel freezers are essentially tubular heat exchangers, jacketed with boiling refrigerant. Inside, barrel freezers have rotating blades that keep the ice scraped off the surface and whip the mix.

During this dynamic freezing process 50% of the water in the ice cream is frozen, and at the same time air is whipped in, which can amount to up to half of the mixes’ volume. Today’s fully automated freezers can produce thousands of ice cream tubs per hour.

Pralines & cream, rocky road and butter pecan… favourites frozen using ammonia refrigeration

General Mills global ice cream phenomenon, Häagen-Dazs, first started as a family-owned business in the 1960s. From its humble beginnings with only three flavours: vanilla, chocolate, and coffee, Häagen-Dazs has expanded to around 50 flavours, sold in 50 countries.

Throughout its North American locations, approximately 90% of Gerenal Mills refrigeration needs are met with ammonia, which includes the Häagen-Dazs ice cream manufacturing facilities.

Nestlé, which has joint venture with General Mills and is a world leader in the ice cream business, also uses ammonia refrigeration in over 90% of its factories worldwide, including its ice cream manufacturing plants.

NH₃ preferred at Unliever

Quirky ice cream brand Ben & Jerry’s ice cream, which features flavours such as Phish Food and Cherry Garcia, is the daughter company of Unilever, which uses ammonia as the preferred refrigerant for industrial refrigeration.

For example, Unilever’s Covington Tennessee plant features a 10,000 ton, two stage/three suction level ammonia refrigeration system. The compressor room provides cooling for production, mix silo, storage freezer, HVAC and distributed glycol systems. A centralised control system allows for critical process temperature control and integration of an ammonia monitoring system.

Weis Ice cream replaces HFCs with naturals & NH3 used by McDonald’s sundae supplier

Well-known Australian manufacturer Weis Ice Cream in Toowoomba, Queensland upgraded its existing hydrofluorocarbon (HFC) based refrigeration and air conditioning systems to a solution using ammonia that gives them almost complete immunity from any commercial risks associated with loss of HFC refrigerants, and future national and international phase-down measures in relation to HFC refrigerants.

Avondale, which has been supplying McDonalds’ outlets in South Africa with their ice creams (the well known McFlurry), milk shakes and other milk products for ten years, also has facilities that include an ammonia cooling plant.