Freeze Drying Temperature Range

[Edco Haglund]

Looking to know more about the Harvest Right freeze dryer? This home freeze-drying machine makes it easy to create freeze dried food at home! Here is my personal review of the Harvest Right freeze dryer after FIVE YEARS of using it non-stop!

After many years of waiting, dreaming, and drooling, I finally purchased my own Harvest Right home freeze dryer. I had originally shared my review after a few months of using the home freeze drying machine.

First, freeze-dryers use extremely cold temperatures (-40 F) and a vacuum to remove 99% of the moisture from a given food. This works because it allows the ice to change directly from a solid into a vapor without passing through the liquid phase.

In turn, the food them becomes shelf-stable for about 20-25 years with proper storage. Until recently, this process of freeze drying was only available to large corporations and operations. Then along came the Harvest Right home freeze dryer!

If you follow me on Facebook, you've seen the many videos I've done since getting my own freeze dryer. There are many items, both whole foods and prepared items (casseroles, desserts, and more) that I have freeze dried live on my Facebook page!

Home freeze dried raw milk, bananas, strawberries, peaches, apples, avocados, gummy bears, cheese, and chocolate chip cookie dough. They are all stored in clean, air tight mason jars with a silica pack to ensure the humidity from the air doesn't lessen the lasting power of the freeze dried food.

While many freeze drying enthusiasts use store bought freeze dried food to show savings, my family (and most families, I would say) doesn't use freeze dried foods on a regular basis. So for me, those comparisons fell flat.

Being able to preserve fresh milk and other dairy products, fresh meat (raw and cooked), as well as fruits and vegetables that don't can well, frees up my freezer space and allows me to fully utilize my entire harvest!

I know there is a lot of talk about freeze dryers being the end all be all of food preservation, and I agree that the shelf life of freeze dried food is far greater than that of canning or dehydrating.

Yes, the freeze dryer main unit hooks up to a vacuum pump that sits to the right, and has a drain hose that routes off the left/bottom. This is included in your purchase. You may choose to purchase a different pump style later on, we never have, but you might!

No. The reason is that during the freeze drying process, ice builds up on the walls of the freeze drying chamber. Attempting to freeze dry more than 10 pounds of food will result in the ice build up getting too thick for the unit to work properly.

The freeze dryer unit has a digital panel that will tell you what phase the process is in at any time, it will also tell you when the final dry time (7 hours) has started and includes a countdown which you can see below! Once the final dry time has finished, you will hear an alert beep to let you know the food is finished! Easy!

Almost anything can be freeze dried! Including: fruits, vegetables, meats, dairy products, full meals, desserts, bone broth, and more. Freeze drying, unlike canning, is safe for pasta and grain based dishes as well!

Generally items that are mostly sugar or fat cannot be freeze dried. Sliced fruit and most desserts are just fine, however, you can't freeze dry things like honey, solid chocolate, or jams/jellies.

And you can freeze dry items like bone broth, milk, cheese, and cream cheese (which all contain fat), but items such as butter that are PURE fat cannot be freeze dried.

Yes, but I would group like items on the same tray. Keep fruits together on a tray, veggies on another, meat on still another... and so on. I've also found that placing stronger flavored items on the upper shelves and milder items on the lower shelves helps keep flavors from mixing.

IMPORTANT: As SOON as the freeze dry cycle is complete, check to make sure that the food is completely dry (if not add more time as shown in the manual), package the food in containers that are moisture and oxygen proof.

This would include mylar bags, mason jars, and tin cans. A silica packet (moisture absorbing packet) is "recommended", but I would say it should be required! Here are the silica packets we use!

The reason for this being that as the temperature rises where your freeze dryer operates, so does the amount of time it takes to finish each batch of food. This happens because in hotter operating temperatures it becomes more difficult to reach the extreme cold required for freeze drying.

Likewise, where you want to avoid extreme heat, you want to avoid extreme cold! Don't operate the unit below freezing as this may cause the water within and below the compressor to freeze and destroy your freeze-drying compressor.

I had a question about my unit, even after reading the entire manual. But I was so excited to get started that I didn't want to page through the internet for the answer. So, I called them up, was connected to a rep in about 15 seconds, and had an answer within another 30 seconds!

Fabulous support and they can help you with questions, as well as getting any replacement parts you might need. They also offer a no interest layaway plan and a no-hassle return policy... though I can guarantee you're not going to want to send it back!

Great article! Thank you for your detailed explanation! We just order our Hatvest Right freezer dryer and it will be delivered in a few weeks! So exciting! I plan to use the Mylar bags but do have one question, should the bags be stored in any certain manner? Hot v cold, light v dark etc ? Thanks !

Freeze-dried food lasts longer and is more lightweight than dehydrated food. Freeze-dried food also retains its color and shape better than dehydrated food. Additionally, more types of food such as ice cream, milk, eggs, and complete meals can be freeze-dried. Despite these advantages, freeze-drying systems are an expensive initial investment, take up a lot of counter space, and use more electricity than a dehydrator.

Trays of food are placed in the freeze dryer's chamber. The machine freezes the food to a temperature between -30 and -50F (-34 and -45C). Next, a vacuum pump pulls the air out of the chamber and the trays are slightly heated. As the water in the food heats, it sublimates (ice is directly converted from solid to water vapor) and is removed from the product. This process automatically removes up to 98 percent of the water in the food.

Some vacuum pumps use oil that must be filtered, while other vacuum pumps are oil free. If the pump you choose uses oil, it is a good idea to purchase extra oil before your initial setup in case you spill any when filling it. Additionally, as the oil is filtered and consumed by the running pump, it will need to be replenished. It is also helpful to purchase a funnel to use when filling the pump with oil.

Start with clean countertops and utensils. Wash hands with soap and warm water. All produce should be properly washed before it is consumed or preserved by rinsing, gently rubbing, or scrubbing with a clean vegetable brush under cold running water. Do not soak produce in water.

Some foods need to be pretreated before they can be freeze-dried to prevent browning. This color change is due to the action of enzymes that act like chemical scissors and cause the food to break down. An example of this process is when an apple is sliced; the exposed flesh turns brown and begins to soften. To control enzymes, follow the same process to pretreat fruits and vegetables for dehydrating as described in "Let's Preserve: Drying Fruits and Vegetables." Food should also be cut into equal-sized portions so that the product freeze-dries at the same rate. The rate at which food freeze-dries should also be considered, and foods with a similar drying time should be processed together. Drying times can vary from approximately 24 to 48 hours. Consult your machine's manual for average drying times.

Raw and cooked meat and eggs can be freeze-dried. However, the freeze-drying process does not kill harmful bacteria that can cause foodborne illness. Therefore, it is important to carefully label raw meat and handle it appropriately before and after freeze-drying.

Freeze-dried food has many uses, including fast meal prep, emergency preparedness, harvest preservation, and outdoor recreation. The food can be eaten "as is" (except for raw meat, poultry, seafood, and eggs), added directly to recipes, or rehydrated and used the same as you would fresh food.

When eating freeze-dried food as is, be sure to drink water since freeze-dried food has a very low water content. Freeze-drying concentrates the flavor of most fruits and vegetables, making them great snack in their freeze-dried state.

Vegetables can be rehydrated and prepared by adding them to a bowl of hot water (or warm water that you microwave or cook on the stovetop). They can also be used directly in cooking, especially when making something like a soup or stew. Do not soak leafy greens because they may get mushy. You can either spray them with some water to rehydrate them or crush them up to be included in sauces, meatballs, or smoothies for added nutrition.

Fruit can be rehydrated by either soaking in a bowl of water or spraying it with water. Fruit is great to use in pies and smoothies, on cereal or oatmeal, or cooked in recipes that call for fresh fruit.

Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process[1] that involves freezing the product and lowering pressure, thereby removing the ice by sublimation.[2] This is in contrast to dehydration by most conventional methods that evaporate water using heat.[3]

Because of the low temperature used in processing,[1] the rehydrated product retains many of its original qualities. When solid objects like strawberries are freeze dried the original shape of the product is maintained.[4] If the product to be dried is a liquid, as often seen in pharmaceutical applications, the properties of the final product are optimized by the combination of excipients (i.e., inactive ingredients). Primary applications of freeze drying include biological (e.g., bacteria and yeasts), biomedical (e.g., surgical transplants), food processing (e.g., coffee), and preservation.[1]

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