Best Practices: Start with the end in mind

Freeze-dried food has entered the home food preservation scene! Domestic freeze dryers have been introduced to homeowners within the past 10 years.  More preservation enthusiasts have ventured into this form of food preservation.  Once a machine has been chosen and placed in your home, there are a few things that you should keep in mind for the best results for your family. 

As with any food preservation method, be sure you start with decent quality food. The better quality of food you use, the better results you will achieve when freeze drying your food.   

Often, we think of food preservation as a means of saving food for an extended period of time, with freeze-drying extending that time beyond other methods. Freeze drying is effective for preserving your garden as well as preparing for possible food shortages or natural disasters. Freeze-drying can offer short-term benefits for immediate enjoyment as well. Fruit freeze-dried today can be enjoyed as a snack tomorrow. Leftover meals can be freeze-dried for a quick family dinner on a busy night or preserved for a camping or hiking trip in the coming months. Garden herbs and vegetables can be freeze-dried and used in recipes for meals throughout the year.  

The process of freeze-drying food has minimal preparation, the processing time may be longer but does not require constant attention, and food may be immediately packaged from the freeze dryer for short-term or long-term storage. While the steps may be simple, there are several tips to make this process more effective.  

Consider these tips:  

• Freeze-drying times are not a fixed number. The amount of product on the tray will impact the processing time, but the good news is that the freeze dryer will adjust without human intervention. 
• Uniformly prepared food pieces optimize drying time. When placing trays into the freeze-dryer, place denser items in the center for the best results. 
• The higher the water content in the food, the longer the processing time. Pre-freezing the food may help reduce processing time.    
• A warmer room temperature will increase the processing time.   
• 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. 
• Be certain to label your jars and bags as “raw” if you have freeze-dried any uncooked beef, poultry, fish, pork, or eggs, don’t assume the freeze-drying process makes your food bacteria-free.  Raw meat should be used right away because freeze-drying does not kill bacteria.  
• Freeze-drying is not considered cottage food.  

Track your journey 

While freeze-drying is not an exact science, it is recommended to keep a journal of all your successes and lessons learned. Keep track of what works for you and your family and document your freeze-drying journey! For more information on freeze-drying, check out the Freeze-Drying: Consider This blog series.  

 Resources: 

Utah State University: https://extension.usu.edu/preserve-the-harvest/research/buying-a-home-freeze-dryer-what-to-know-before-you-go   

https://harvestright.com/wp-content/uploads/2019/09/GUIDE-TO-FREEZE-DRYING.pdf (retrieved on 11-2-2023) 

Melanie Hausch, food preservationist and subject matter expert, Bryan, Ohio  

Written by: 

Emma Horstman, Extension Educator, Ohio State University Extension, Paulding County 

Melissa J. Rupp, Extension Educator, Ohio State University Extension, Fulton County 

Reviewed by: 

 Ohio State University Extension, Food Preservation Team  

Photo Credit:  

Laura Halladay, Extension Educator, Ohio State University Extension, Greene County.  

Good reasons to freeze-dry 

Freeze-drying has long been used by outdoor enthusiasts for lightweight snacks and complete meals on the trail; but did you know freeze-dried foods are also great for quick and healthy snacks, traveling, easy meal preparation, emergency preparedness, and even homemade pet food.  

Freeze-drying is a terrific way to reduce food waste and preserve the harvest. You may be asking “What types of food can I freeze-dry?” Fruits, vegetables, meats, dairy products, desserts, and complete meals can all be effectively freeze-dried. 

Good Health 

Freeze-drying is a food preservation process, not a food safety process. It will not make unsafe foods safe. It is important to remember that freeze-drying does not destroy enzymes or microorganisms. Enzymes are less active but are still present and can lead to reduced food quality over time. If the goal is long-term storage, consider blanching vegetables and treating fruit that is prone to browning. Microorganisms will become inactive but are not killed.  

If raw, fresh produce is contaminated, those same contaminants will be on the food when it is eaten. Special considerations must be made when eating freeze-dried animal products that have not been cooked (eggs, meats, poultry). These foods should be labeled “raw” and must be heat treated prior to consuming. 

Good Nutrition 

Color, flavor, shape and approximately 90% of the nutritional value of the food are maintained. The freezing process occurs very quickly thus reducing nutrient loss and retaining food quality. The drying process allows the food to be lightweight and shelf stable. While food weight is reduced, the volume of food may not be reduced. Many items retain their shape when freeze-dried. An exception is high-water content liquid items like soup, milk, and eggs which become crumbly and powder-like. These foods are often rehydrated back to their original volume before being consumed.  

The calorie content by volume may be similar to the original food item for products that retain their shape, or it may be higher for foods that crumble or become powders. Additionally, salt and sugar become more concentrated, so salty foods will taste saltier and sweet foods will taste sweeter. The vitamin and mineral content will be unchanged. You may need to increase your fluid intake when consuming freeze-dried foods. 

Please note that freeze-dried foods are not allowed as cottage foods in Ohio. 

These are just a few things to consider as you explore freeze-drying. It is up to you to determine the benefits and drawbacks for you and your family. Please read each of the Freeze-drying: Consider This blog articles for more information! 

Freeze-Drying: Consider This 

Freeze-Drying: Consider This – Food Dehydration, Freezing, and Freeze-drying 

Stay tuned for the final article in the series! 

Resources: 

Bhatta S, Stevanovic Janezic T, Ratti C. Freeze-Drying of Plant-Based Foods. Foods. 2020 Jan 13;9(1):87. 

Geiger, M. Iowa State University Extension Preserving by Home Freeze Drying Blog. 2023 June 13. https://blogs.extension.iastate.edu/answerline/2023/06/13/preserving-by-home-freeze-drying/  

Kupletskaya, M.B., Netrusov, A.I. Viability of lyophilized microorganisms after 50-year storage. Microbiology. 2011; 80 (6): 850.  

Yukie Miyamoto-Shinohara, Takashi Imaizumi, Junji Sukenobe, Yukie Murakami, Sugio Kawamura, Yasuhiko Komatsu, Survival Rate of Microbes after Freeze-Drying and Long-Term Storage. Cryobiology. 2000 Nov; 41(3):251. 

Written by: 

Christine Kendle, Extension Educator, Ohio State University Extension, Tuscarawas County and Kate Shumaker, Extension Educator, Ohio State University Extension, Holmes County. 

Assisted by Tiffany Haney, Intern, Stark State University Dietetic Technician Program. 

Reviewed by: Ohio State University Extension, Food Preservation Team. 

Photo Credit: Laura Halladay, Ohio State University Extension, Greene County