Make the Most of Your Perishable Foods

Keep food longer and make snacks fun by freeze-drying

By Robin Howard

Freeze dried berries and applesPreserving food has deep roots in the South. In a geography hit hard by war, political upheaval, and the Great Depression, survival often meant preserving whatever food you could grow.

With the era of victory gardens behind us, many of us became used to going to the grocery store for inexpensive canned, boxed, or frozen food.

That is until The Great Recession gave us a wake-up call.

During the recession, food became more expensive, and money didn’t go as far. For some families, preserving food seemed like a good idea again. Many of the folks who dug out their grannies’ old canning rigs to save money on food found they enjoyed the other benefits of preserving food, including reducing food waste, controlling allergens, and eliminating preservatives and chemicals.

While adventurous home chefs have revived canning, others have experimented with a more modern method of preserving food: freeze-drying.

Freeze dried berriesIf freeze-drying conjures up nostalgic images of space food, I must break the news: It’s not a new process.

The Incas freeze-dried crops as early as the 15th century. They would freeze corn and potatoes by placing them in high crevices in the cold mountains above Machu Picchu. After the crops froze solid, water vapor trapped inside slowly evaporated due to the high altitude. The result was freeze-dried corn and potatoes that would last until the next harvest.

With the industrial revolution came the first freeze-drying machine. Created to preserve scientific specimens, the device was later used to preserve blood for transport during World War II.

In 1968, freeze-drying entered the common lexicon when Apollo astronauts made the wise decision not to leave Earth without dessert. As a culture, we became fascinated with astronaut ice cream. How did they do it? How does it taste? How long would it keep? With the invention of the home freeze dryer, we now have some answers.

How Freeze-Drying Works

Industrial strength freeze dryers such as the ones NASA used to create arid blocks of Blue Bunny are about 20 feet long and 9 feet high. You probably wouldn’t want one in your pantry. However, today’s home freeze dryers are about the size of a microwave.

Inside a thick Plexiglas door are small metal trays on which you place thin slices of food. The temperature inside the machine lowers to -40 degrees F, freezing food rapidly. The appliance’s powerful vacuum then removes water vapor as it gradually warms, leaving food that has all of its original flavor and nutritional value, but is dry enough to crush into a powder.

Most freeze-dried food, such as ice cream, is fun to eat as it is. Freeze-drying makes everything crunchy and intensely flavored. However, you can rehydrate food by spritzing it or soaking it in warm water until it returns to its original consistency.

If appropriately stored in tight containers or vacuum-sealed bags, freeze-dried food can last up to 25 years with no temperature control.

Foods That Freeze Dry

While canning food has limited applications, almost any food can be freeze-dried. All fruits, vegetables, and meats can be freeze-dried, as can eggs, pasta, casseroles, and some desserts, including ice cream and marshmallows.

There are even stories of people rescuing wet smartphones and waterlogged books by running them through a freeze dryer.

The only foods that don’t do well in a freeze-dryer are foods with high sugar content, such as honey; and high-fat content, such as butter.

Is It Worth the Expense?

Portable freeze dryers cost between $2,000 and $3,000. Each 24-hour freeze-drying cycle requires about 1,200 watts of energy an hour, at a cost of about $3 a day. These mini machines can freeze dry about 4 pounds of fresh food in a batch, or about 900 pounds of food a year if run continuously.

There are maintenance issues to consider as well. Most home freeze dryers have an external vacuum pump that requires an oil change after every cycle. Changing the oil isn’t hard—and it can be filtered and re-used—but it does add to the expense.

If you’re only going to use your freeze dryer a few times a year, the cost won’t make sense. If you’re dedicated to building a cache of meals for emergencies, road trips, or everyday use, it could pay for itself relatively quickly.

If saving money is your primary motivation, the key to making a home freeze dryer payoff is organization: Plant a well-planned garden, take advantage of bulk sales, and batch cooking so there are leftovers.

Depending on your situation, there are plenty of other ways a home freeze dryer might make life easier. For example, if you own an RV, packing freeze-dried meals for road trips can quickly save you enough to justify the appliance.

Food allergies are a common reason for the growing popularity of freeze dryers. Food allergies affect 13 million Americans, or one in 12 children. If you or someone in your family has to carefully avoid certain ingredients, packing freeze-dried meals to rehydrate at home, school, or while traveling can be a lifesaver.

Pet owners also are jumping on the freeze-drying bandwagon. With the rash of pet food recalls in the past several years, more people are making pet food at home. Home freeze dryers allow pet parents to control the ingredients in their dog or cat’s food and treats, eliminating allergens and avoiding unsafe ingredients.

In the end, freeze-drying may not be any less labor-intensive or money-saving than other methods of food preservation. However, practical benefits may be a significant advantage for some people.

After all, how can you put a price on the ability to make your own astronaut ice cream?