Cool runnings: Cryogenic sauce chilling in an instant

Linde’s ACCU-CHILL SC® uses liquid nitrogen to cool scalding sauces – serving seasonal trends and convenience food industries worldwide.

It was the image of a typical 20th century Western society household: father, mother, son and daughter, referred to by sociologists as nuclear family. But times are changing – and so are people.

In fact, households are increasingly living in non-traditional ways. One of the key changes: singles living alone. About two thirds of EU households consist of one or two persons, with single households alone accounting for 33%, according to Eurostat. This has profound implications – for the food business in particular.

Along with living alone, there has been a trend towards more flexible meals due to factors like busy lifestyles and work-life-blending, Euromonitor found. People take to consumable convenience cuisine, light meals and healthy snacks, often picked up at city stores and take-away eateries.

A step change in cooling foodstuff

With ACCU-CHILL^® Sauce Cooling (SC), Linde is taking efficient chilling of hot liquids such as soups to the next level, serving increasingly diverse tastes and trends in a growing market.

The ACCU-CHILL SC^® is a step change in chilling foodstuff – perfect for in-line as well as batch productions to meet modern society’s nutritional needs. Its key advantage: Efficiency. Conventional cooling tools such as kettle chillers, traditional heat exchangers or scraped surface heat exchangers demand much energy, space and time, which can result in low daily output. ACCU-CHILL SC^® tackles this challenge – by pioneering cryogenic gas cooling with an unprecedented energy efficiency of up to 90%.

The ACCU-CHILL SC® – ideal for rapid, reliable in-line sauce cooling.

Smoothie — The ACCU-CHILL SC®’s secret formula? Direct injection of liquid nitrogen.

Food-chilling in a flash

The secret formula? ACCU-CHILL SC^® uses BiogonN nitrogen (N₂) as a refrigerant. Extracted from the air, the (purified) gas is chilled to -196°C. It becomes a liquid. By injecting nitrogen directly into hot sauces, soups, dips, marinades or fruit purees, the temperature of the products is reduced from around 90°C to 4°C in just a few seconds – without freezing them.

That helps cut cooling times by more than half compared to traditional solutions. With a 280°C thermal delta between the cryogenic and the hot liquid, ACCU-CHILL SC^®’s injection system reaches high heat transfer rates in a very efficient manner, leveraging the nitrogen’s full cooling power.

Preparing ready-made smoothies, for example, just got a whole lot easier: Heated up to 80°C for preservation, pineapple puree, for example, can quickly be cooled down to a 10°C liquid. Put into a pellet freezer, it can be shipped to serve summer trends and seasonal occasions.

In the (mixing) zone: The perfect whirl

But how does the process work? After heating the sauce in a kettle, it is pumped into the tubular mixing chamber. This is where the magic happens: Liquid nitrogen is injected into the stream of simmering sauce through 24 specially designed nozzles, creating a perfect whirl. In this turbulence, both parts instantly blend into a chilly mixture.

As the volume of one kilogramme liquid N₂ is eight times smaller than that of gaseous N₂, it rapidly expands once it hits the hot fluid, supporting the blending process. Once the chilled mixture reaches the cooling kettle, an agitator ensures a smooth heat distribution in the sauce. Meanwhile, the system monitors the sauce’s temperature at all times and adjusts the pump speed, if needed. And the nitrogen? Just about 0°C cold, the gas escapes into the air through overhead vents – a natural cycle.

There is just one catch. Whether it’s sauce, soup, dip, gravy, condiment or custard you’re cooling: The product must be pumpable. A sauce’s viscosity, determined by a viscometer, should be above the value of five to be suitable for nitrogen injection. Pastes, mashes and bakery doughs are usually chilled through a different technique (Bottom Injection).

Minimising cost, maximising output

Not only is the ACCU-CHILL SC^® portable and space-saving, it’s also rentable. Merging right into customers’ production lines, it helps them maintain maximum flexibility. That makes it the ideal solution for those planning to increase production volume – and those preparing cool commodities for short-term markets without extra investment costs. There’s a total of four ACCU-CHILL SC^® up and running, two in the U.S. and two in Europe. It’s not without reason that it has taken home the International FoodTec Award 2018’s gold medal, awarded by the DLG (German Agricultural Society). Our eating habits and diets may be changing – more flexible, more individual –, but our preference for quality nutrition and healthy meals remains the same.