Seeking Freezer Freedom

A portable standalone container that keeps frozen treats at serving temperature during special events is something of a holy grail. In summer especially, it hovers, frosty and steaming, in the minds of caterers and their clients throughout the ice cream-eating world.

Just imagine serving that sorbet at its peak flavor, texture, and mouthfeel without a thousand-pound freezer plugged into a wall or, costlier still, a portable generator? Dry ice is nice, but only for the short term, and won’t freeze product evenly at the best of times. A few highly skilled operators use liquid nitrogen to prepare treats from scratch on site. Even then, the downside potential of handling gas and, frankly, poisoning the wedding party outweighs most hosts’ insurance coverage–never mind the provider’s.

Some of us got excited when Yeti came out with their high-performance “overbuilt” coolers, only to learn that they’re only as powerful as the seal on the lid. The Yeti people themselves explain, “There are many variables that affect ice retention, such as frequent lid opening, outside environment, placement in direct sunlight, etc. Careful attention to these simple details will significantly extend ice retention.” Open the lid too often, in other words, and be prepared for a meltdown.

Tie Dye-Looking “Tech”

Carlisle’s Coldmaster products are insulated with gel that freezes like the stuff in portable ice packs. Eight hours in the freezer gives these products enough chill power to keep food below 40 degrees for eight hours, given an air temperature of 76 degrees Fahrenheit.

Now, you kids at home can reproduce the low melting point, heat capacity, and gooiness of this gel by combining water, glycerin, and a thickener such as xanthan gum. But it takes a rarer recipe to prevent the liquid’s expansion as it drops below 4 degrees Celsius, the temperature at which liquid water is most dense. Manufacturers like Carlisle may use cellulose, polyvinyl acetate, polypropylene beads, or other trade-secret substances, most of them nontoxic, to nail the freezing properties of this gel without damaging its container.

To this zesty ragout, Carlisle has added “patent-pending technology” (more trade-secret gunk?) that changes the CoolCheck containers’ color from blue to white during thaw. According to Carlisle, this “tells” workers when food temperature is safe–according to us, in the way toddlers “tell” you they needed to go to the bathroom ten minutes ago, i.e., by revealing on inspection that they already went.

Over our 8-hour test, as the frozen treats went from 16 to 23 degrees Fahrenheit, the divided tub took on a white-to-blue ombre gradation from the top down–nothing more accurate. As well, since the pans are built to insert in a cooler template, it was hard to imagine a server either levering one out of its hole or viewing it from underneath the cutout to ascertain color change.

A Risk-Averse Business

We imagine, however, that by virtue of timing alone, Carlisle should have a winner with this line, even if they do overstate its “communicative” properties. As a risk-management feature, CoolCheck allows kitchen managers to set safe-service criteria with color rather than, say, insisting on (ha!) temperature checks. Along with the arsenal of purple-lidded “allergy-aware” storage on view at this year’s trade shows, CoolCheck belongs in the armory of blunt instruments color-coded to fight public-health–and business–disasters.

On that note, we’d like to underscore that temperature is only one little variable in how food changes chemically. Indeed, Listeria holds its own in much colder temperatures than most other bacteria can survive, which is why Blue Bell and Jeni’s had to yank the supply chain from retail backwards when that bacteria was found in their manufacturing facilities.

The desserts we made–an egg custard-based Mexican vanilla ice cream and a citrus-y hibiscus sorbet–went into the “charged” (really just chilled) CoolCheck tub frozen to soft-serve temperature, around 22 degrees, and consistency. Watch the magic right here:

And with minor variations over the daylong test–at Hour 4, for example, we discovered that someone had been eating our helado (it was Cinco de Mayo so we forgave them)–they stayed on temperature: between 16 and 23 degrees.

In consistency, not so much. Both the ice cream, with its higher fat content, and the sorbet, with its higher sugar ratio, changed texture significantly over the hours of the test. What started out scoopable went to slush, then soup, but within only 2-5 degrees. Who knew?

Our Conclusions

For our part, we’ll never trust temperature alone again. And hey, Carlisle, if an easily lift-/lowerable lid could keep the contents colder, we’d suggest you add it to the CoolCheck line. Might as well do something to keep invaders at bay while we wait for a revolution.

Elaine Evans
Elaine Evans Elaine Evans is thrilled to blog for KaTom, where her work in restaurants, bars, catering, and artisanal food has caught up at last with her career in journalism and public relations writing.
  1. May 23, 2015 at 10:30 pm, Dennis Duffy said:

    For a Canadian, this talk about cold is ultimately terrifying.