Want to learn more about freeze drying foods? I can help

I am a bit of a food processing nerd. My master’s thesis was titled “Effects of high pressure processing on the microbiological, physical and sensory properties of pasteurized fluid milk products.”

High-pressure processing was a newer technology in the early 2000s. Now, we enjoy foods from the grocery store that benefit from this type of processing rather than high heat processing like juices, baby foods, seafood and, especially, guacamole and other avocado products.

This high pressure technology is only used on a commercial scale. Consumers are not rushing out to buy gigantic machines for hundreds of thousands of dollars to use at home. But they are rushing out to buy a different kind of food processing technology. The freeze dryer has gained huge popularity in just a few years as smaller units are being produced here in the U.S. and around the world.

According to the FDA, freeze drying is known technically as the process of lyophilization. This is “a process in which water is removed from a product after it is frozen and placed under a vacuum, allowing the ice to change directly from solid to vapor without passing through a liquid phase.”

It is a multistep process with three separate, interdependent processes. The first step is freezing. Then there are two different drying steps – sublimation and desorption. One thing that makes freeze drying unique is many of the food products retain their original texture, flavor and nutrients once reconstituted.

People get interested in freeze drying for a variety of reasons. It can allow you to have shelf stable food in case of emergencies. It is a way to produce healthy snacks with fruits and vegetables. It can help to reduce food waste, especially when you have an abundant garden. And freeze-dried foods are light and portable, making them perfect for camping, hiking and hunting.

The freeze drying process is similar to dehydrating, but it is much more involved and requires special equipment. A home freeze dryer looks like a small front load washing machine. It contains racks on which trays can be loaded. Depending on the food you are freeze drying, the process can take a few days. The freeze dryer will adjust the time without human intervention. Almost all foods can be freeze-dried, but for the best results, avoid oily foods including butter, peanut butter and chocolate. Also, for more success, refrain from using honey, syrup and jam.

Currently, a home freeze dryer costs from $2,000 to $6,000. One of the most popular brands is Harvest Right, a company in Idaho. But there are several other brands producing home freeze dryers including Stay Fresh and Blue Alpine. They can weigh from 100 to 200 pounds depending on the size of the unit. Most companies are making a smaller and larger capacity machine and some have a medium option and even an extra large option. This is definitely not a machine you keep on your kitchen countertop.

This summer, I will teach a freeze drying fundamentals class from 6 to 7:30 p.m. July 16 at Schumaker Farms, 52441 County Road 16. We'll talk about equipment, logistics and taste some freeze dried foods.

Ohio State University Extension in Morrow County is generously lending us their freeze dryer to prepare food for the class. Participants will be able to view the equipment and see how the controls work during the class. The class is free, but pre-registration is required at go.osu.edu/coshoctonfreezedry. You can also learn more about freeze drying on the OSU Extension Live Healthy Live Well blog at livehealthyosu.com.

Today, I’ll leave you with this quote from Pearl S. Buck: “Praise out of season, or tactlessly bestowed, can freeze the heart as much as blame.”

Emily Marrison is an OSU Extension Family & Consumer Sciences Educator and may be reached at 740-622-2265.

This article originally appeared on Coshocton Tribune: Freeze drying foods is on the rise with consumers