For as long as people have been eating, we’ve been searching for healthy, efficient ways to preserve food longer. All around the world, every culture has developed its own techniques for specific foods: Whole eggs smothered in oil, vegetables buried underground to ferment, and meats wrapped in gelatin. These days, the foods you find in a grocery store can be preserved in a multitude of ways including canning, dehydration, refrigeration, freezing, or brining. And then there’s freeze drying.
The wonder of freeze drying
One of the first documented instances of the freeze drying process was developed several thousand years ago atop the towering Andes mountains, in the Puna grasslands of Peru. Local indigenous peoples noticed that if they allowed potatoes to freeze in the frigid mountain nights and then set them out in the sweltering daytime sun, the vegetables would dry out quickly and remain unspoiled for much longer. Thanks to this discovery, the peoples of the Andes were able to eat nutritious and flavorful food year-round. But it would be thousands of years before the rest of the world caught up.
Today we use these same concepts and apply 21st century technology to get even better, more consistent results. What the indigenous people knew — and what has recently been confirmed by scientific researchers — is that freeze drying locks in nutrients (along with flavor) much better than other drying methods.
During World War II, freeze drying was used on a large scale as a way to transport plasma to and from hospitals in Europe. Freeze drying safely preserved blood plasma, made it lightweight for travel, and preserved it perfectly, ensuring that it was ready to rehydrate without degrading. If this method could preserve plasma long term, the next logical step would be to apply the same technology to food.
A nutritional powerhouse
One key advantage of freeze drying is that the food is preserved at the peak of ripeness and nutrient content. This compares favorably with fresh produce. To ensure that produce is ripe and ready to eat at the grocery stores, it must be picked days or even weeks earlier, long before it’s actually ripe. The assumption is that the produce will continue to ripen as it travels, but the ripening of produce is an inexact process that keeps fruits languishing in the produce bin at the store. Imagine if produce was allowed to ripen on the plant, picked it at peak ripeness, and then preserved until consumers were ready to eat it? This is the benefit of freeze-dried foods.
A 2004 study of fresh blackberries found that levels of antioxidants were four times greater in ripe blackberries compared to underripe versions of the same fruit. With freeze drying, fruits and vegetables can be picked at their ripest, when produce is packed with nutrients. In this way, freeze-dried foods can be even better for health than fresh foods.
Vitamin A (which has an important role in the health of your eyes, bones, and immune system) along with vitamin C starts to break down fast in traditional dehydrators. But freeze drying halts that degradation and keeps the vitamins intact.
Freeze drying is so effective, in fact, that studies on the potential for cancer prevention are often done with freeze-dried food. You’ve probably heard that multiple studies have found cancer-fighting properties in berries; Much of that research was led by Dr. Gary Stoner at the Medical College of Wisconsin, using freeze-dried strawberries and black raspberries.
The problem with sulfites
Sulfites are preservatives, often added to dehydrated fruits and vegetables. Though these chemicals change the flavor, they’re added to dried fruit because they help fend off microbes, halt discoloration and retain certain vitamins. But the flip side is that sulfites destroy other vitamins. While vitamin C is preserved well when sulfites are added, vitamin B1 degrades in the presence of sulfites. On top of all of this, many people find their digestive systems are sensitive to the sulfites, while others can actually be allergic to it.
And don’t forget about dairy
Cheese and yogurt might not be the first food products you think of when you think of freeze drying, but in fact, freeze drying is the best way to preserve the nutrients and probiotics in dairy. Freeze-dried cheeses rehydrate easily, and once rehydrated melt just like fresh cheeses. Freeze-dried yogurt is even easier to eat. Many people love to snack on it while it’s still in its freeze-dried state. Fresh yogurt requires a spoon and bowl, but freeze-dried yogurt is a no-mess snack with a delightful crunch. Even more importantly, though, freeze-dried yogurt actually retains the probiotic cultures that are so important for healthy digestion.
From ancient civilizations to cutting-edge labs, there has been a never-ending journey to develop food preservation techniques that provide the best flavor and most nutritional value. Mercer Foods is thrilled to be at the forefront of this endeavor, constantly perfecting the methods we use. What we’ve learned along the way is what the indigenous peoples of the Andes knew all along: Freeze drying keeps food fresher and healthier than any other preservation method.