How to Use a Freeze Dryer & Tips

We have freeze dried thousands of pounds of food over the years. So it’s about time I wrote out a basic guide of how to use a freeze dryer. It’s a pretty simple process, but there are some things to know about maintenance and additional helpful tips. 

What is Freeze Drying?

First off, let’s start with some basics. Freeze drying requires a freeze dryer. It’s not like dehydration where you can substitute your oven for a dehydrator. 

This post contains affiliate links. Here is the full disclosure.

The reason for that is freeze drying is a process in which a completely frozen sample is placed under a vacuum in order to remove water, allowing the ice to change directly from a solid to a vapor without passing through a liquid phase. 

The more scientific word used to describe that process is called sublimation.

How to Use a Freeze Dryer

I use a Harvest Right Freeze Dryer. Harvest Right has a TON of information on how to use a freeze dryer to and I recommend following the manual for basic set up. However, I wanted to add some pictures of how easy it is to run and use.

First Time Use (Bread Batch)

Before you get started… This guide assumes you have everything set up and ready for your first use of the freeze dryer by following the manual included with your freeze dryer.

We have a premier oil pump but you can also get electric for an added cost.

For your first batch, remember to do a test run. This is done to make sure the freeze drier is in working order and it gets rid of the factory smell.

To do the bread test batch, get some very cheap bread at the store. Since you’ll be throwing it away after, quality doesn’t matter. Then get the bread moist by dipping them in water or spraying them with a spray bottle.  Follow the steps below to run the freeze dryer!

Side note: Since the bread is absorbing factory smells and off gassing, I don’t even feed it to my animals after it’s done.

Running a Normal Freeze Dryer Cycle

During a normal batch, before adding any food to the freeze dryer you have two choices. You can freeze the food in a freezer, or you have the freeze dryer freeze it for you.

The reason to freeze the food in a freezer is energy savings and it saves time. A designated freezer’s sole purpose is to freeze food and keep it frozen. Therefore, it’s much more efficient at performing that action. 

If freezing trays in advance, all trays must be frozen. You can’t mix non frozen food with frozen in one batch.

When it comes time to freeze dry the food, you don’t need to specify that your trays are already frozen. There is some pretty cool technology that senses which type of food you put in.

How To Use a Freeze Drier: Step by Step

That’s it! Isn’t it so simple? I was intimidated the first time using it but quickly realized it would be hard to mess it up.

Freeze Dryer Tips

Don’t Skimp on the Accessories

First, get some key accessories. I highly recommend silicone mats and tray lids. They don’t come with the freeze drier but I use them often. Actually, we have both a medium and an extra large freeze drier and I don’t have the mats for the medium.

The other day I was freeze drying cranberries with apple cider and I regretted not spending the extra money to get some mats! The cranberries were delicious but they stuck to the trays like glue. 

You can always use some parchment paper in a pinch. I ordered the silicone mats right after but until they get here I’ll be using the parchment paper to run another batch.

Get the Right Size Freeze Dryer 

While there isn’t a goldilocks of freeze dryers, do your best to get the right size freeze dryer at the outset. We initially got a medium freeze dryer. Since we are a family of 7 (almost 8) and have a large garden, we do mostly big batches of food. 

I felt like the medium freeze dryer was constantly running because we couldn’t fit everything in one batch. 

Later, we got an extra large freeze dryer and it’s the right size about 90% of the time. 

Here is some additional information on freeze dryer pounds of food for each size. This is sourced from Harvest Right’s website.

• Small Freeze Dryer the capacity of each batch is a 6 to 10 lbs. of fresh food.
• Medium Freeze Dryer the Capacity of each batch is 10 to 15 lbs. of fresh food.
• Large Freeze Dryer the capacity of each batch is 18 to 27 lbs. of fresh food.
• X-Large Freeze Dryer the Capacity of each batch is around 40 to 50 lbs. of fresh food.

I think these numbers are inflated. Based on my personal experience, if you are spreading food on the trays evenly or freeze drying slices of fruit, you don’t get near these numbers. 

What matches up better realistically is if you look at the pounds on the next size down. For example, my medium size freeze dryer can do about 6 to 10 lbs of fresh food per batch.

A Note about Freeze Dryer Electrical

We were a little surprised that once you get into the Large and XL freeze dryer size you need a 110 volt (NEMA 5-20) outlet. Our extra large is considered “Commercial Size”.

A dedicated 20 amp circuit is required too. For the small and medium size freeze dryer you can use any normal outlet.

We hired an electrician to put the 110 volt Nema 5-20 and dedicated circuit in our garage. It was a couple hundred dollars if I remember right and didn’t take long to install. I think it was very worth it for the added capacity of the XL freeze dryer! 

I say all that because I wouldn’t let that electrical requirement stand in the way of getting the size you actually want. As long as you know of a good electrician, it’s no hassle at all. 

Foods You Can’t Freeze Dry

There is a pretty wide variety of foods you can freeze dry. So it’s faster for me to make a list of what you can’t freeze dry. These are noted in the book, Discover Home Freeze Drying by Harvest Right.

1. Peanut butter
2. Jams
3. Butter
4. Honey and Syrups
5. Chocolate
6. Oils

These foods can’t be freeze dried alone. However, if they are included in other foods and recipes with several ingredients, they will often freeze dry with no problems.

Where our Freeze Dryer is Located and The Set Up

The ideal scenario is a room that is climate controlled but isn’t in your home. There are a couple reasons for this ideal. One reason is that the freeze dryer doesn’t like it when a room is too hot. It still works but says it’s going to take longer.

Another reason to have in a climate controlled area outside your home is that the freeze dryer is loud. It sounds about as loud as a clothes dryer. The third reason is the freeze dryer needs to drain out water. I’m not comfortable having a tube with melting water coming out in our home (even if it has a bucket under it).

We have both our freeze dryers in the garage. The garage is good place until it gets hot in summer. Otherwise, it’s perfect in my opinion. There is a concrete floor that isn’t ruined by the occasional water spill and the noise is outside.

When we had a medium size freeze dryer we had it on a table. I was always afraid the table would buckle under the weight of the freeze dryer. It never did thankfully.

Freeze dryers are HEAVY and you need a table that is strong and sturdy. When we got our extra large freeze dryer, I told Cam we needed a different set up.

He was going to build a table but because the freeze dryer came quickly and we wanted to test it out, he put together a table made out of pallets. It is very sturdy and strong!

Even though it doesn’t look pretty, I was so happy with how strong it was and the functionality of it, we never built the other table.

Cam drilled a hole for the hose to go through so we could put a bucket under the table to catch the water when it defrosts. It works great.

What we Make With the Freeze Dryer

Most of what we freeze dry is simple one ingredient foods. Our favorites are freeze dried fruits like strawberries, peaches, blueberries, and apples. However, we also freeze dry herbs, vegetables, and meat too!

When I had an over abundance of sweet potatoes, we made freeze dried sweet potato chips. We’ve also freeze dried pizza sauce and made different foods in to powders like hatch chili powder and freeze dried garlic scape powder.

I use our freeze dryer all the time. But it’s not the only way we preserve food. We like to have some variety so we also do some canning, dehydrating, freezing, and fermentation.