Trends in Retort Processing: Goodbye Canned Food, Hello “Retort Pouches”
By: Priorclave North America
Categories: Front Loading Autoclaves Steam Autoclaves
For hundreds of years retort processing (i.e., “canning”) has made it possible to prepare spaghetti sauce in minutes—instead of hours—eat tuna regardless of how many thousands of miles you live from an ocean, and have veggies year-round.
In terms of the production workflow and equipment, food and beverage retort processing has changed very little since the early 1800s:
- food is loaded into steel cans
- the cans are sealed
- the sealed cans are dumped into baskets
- the baskets are loaded into “retorts” (i.e., room-sized steam autoclaves)
- the sealed cans are autoclaved at about 235º for about two hours
- the cans are cooled, inspected, labelled, and shipped
- you buy the can, opened it, heat up your SpaghettiOs, and, Voilà! Bon appétit, mon chéri!
It’s a good technology, but an old one: Cans are heavy and bulky. Not only are they resource intensive to process, but also to ship and handle. On top of all that, they’re plagued by “retort flavor“—the the flat, often metallic taste typical of canned foods. Subsequently, they’re often loaded up with salt and sugar to make them more palatable—and, unfortunately, much less healthy than they could be.
Increasing Efficiency and Convenience while Eliminating Retort Flavor
The solution is the increasingly common “retort pouch.” These are heavy-duty plastic pouches, originally developed for the U.S. Army’s MRE (“Meal, Ready-to-Eat“) field rations. They’re processed almost identically to canned foods (i.e., fill, seal, heat, ship, eat), but offer three key advantages:
- Efficiency—Because the retortable pouches have both a thinner profile and better thermal conductivity overall, they heat considerably faster in the retort.
- Flavor—Shorter heating times doesn’t just save energy, it also protects flavor and aroma; people invariably report that pouched foods taste “fresher” or just plain “better.”
- Convenience—This isn’t a matter of the lazy consumers who can’t be bothered with cranking a can opener. Children, those with limited mobility, and especially elders are often unable to open traditionally retort-processed cans without assistance.
The one downside is that, while durable, retort pouches will burst during retort processing, due to the pressure changes that come with that high-heat process. The solution (as with autoclaving sealed flasks) is an air ballast system (in food processing this is often called “air overpressure”).
Production scale overpressure retorts are a big investment. This has slowed the shift to retort pouches. Because of our experience building custom research-grade autoclaves, Priorclave has been able to partner with food and beverage producers to outfit them with air-ballast autoclaves for new product development. These can precisely mimic the conditions in a large overpressure retort, but at a smaller scale. They can work out all the kinks—from packaging issues to audience testing and fine-tuning their recipes—before taking the plunge into the pouch.