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How to Freeze Dry Mashed Potatoes (4 Ways) + Rehydration Instructions

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With their starchy, hearty texture, there is no doubt potatoes are a filling and comforting food, and what better way to eat them than mashed with lashings of milk and butter?

In an attempt to develop the perfect method of freeze-drying (and rehydrating) mashed potatoes, we have tried four different methods.

Discover what worked, which methods we would repeat and the best technique for freeze-drying mashed potato in this article!

Freeze-Drying Mashed Potato – 4 Ways

Before I get into the technique for freeze-drying mashed potato, here are the four variations we tried:

Tray 1: Potato, skin on, mashed with water, freeze dried and left chunky.

Tray 2: Potato, skin on, mashed with water, freeze dried and roughly powdered with a Vitamix.

Tray 3: Potato, peeled, mashed with butter, chives and milk, freeze dried and left chunky.

Tray 4: Potato, peeled, mashed with butter, chives and milk, freeze dried and roughly powdered with a Vitamix.

Freeze dried mashed potato - Four Ways
Four different methods of freeze-drying mashed potato.

The purpose of trying all 4 methods was to establish whether powdered or chunky mashed potato was easier to rehydrate.

We also wanted to see how well ‘complete’ mashed potato – that is, potato already mashed with butter, milk and chives – would freeze dry and rehydrate versus potato mashed with just water and rehydrated with a combination of water, milk and butter to make it a more traditional mashed potato.

Due to the higher fat content, and therefore possibly diminished shelf-life, of the potato mashed with butter and milk, we don’t plan to add that variation to our long-term (2+ year) emergency food stores.

We will use this in the shorter term for camping trips as it is an easy way to have mashed potato in the bush while carrying fewer supplies. However, the water mashed version will definitely be added to our long-term stores.

Don’t have a freeze-dryer yet and wondering if this appliance is right for you? Read my two-year, hands-on, no-holds-barred review of the Harvest Right freeze dryer here.

Harvest Right Freeze Dryer
  • Freeze dry up to 10,000 lbs of fresh food every year.
  • Preserve your gardens harvest & prepare for emergencies.
  • Make your own camping & hiking meals.
  • Freeze dry your own pet food.

Step-by-Step Guide to Freeze Drying Mashed Potatoes

For all variations of the mashed potato, steps 1-3 were (almost) the same and are as follows:

1. Wash and/or Peel the Potatoes

First off, give your potatoes a good scrub with a vegetable scrubber. We found you can fit between 3.3-4.2 lbs (1.5-2kg) potato per medium freeze dryer tray once mashed.

You might also like to peel them at this point (this really comes down to personal preference). We did half/half, leaving the skin on the water mash batch, and peeling the milk/butter mash batch.

To peel the potatoes, we used the peeling attachment in our Breville Sous Chef. It was our first time trying this function on the machine and we were thoroughly impressed (peeling 6 potatoes in less than 30 seconds is a win for me)! The Sous Chef is also very handy for making freeze dried shredded potatoes (hash browns).

If you have large amounts of potatoes to process, do yourself a favor and check it out.

Clean and peel the potatoes
Washing potatoes (left) and peeling in the Breville Sous Chef (right).

2. Dice the Potatoes

Next, it is time to dice the potatoes. You can do this by hand but again, the Breville Sous Chef is fantastic for this job.

We were processing large amounts of potato (26.5 lbs / 12kg) and using the 16mm dicing attachment on the Breville we had uniformly diced potato in no time.

Potatoes diced in Breville Sous Chef
Potato cubes diced by the Breville Sous Chef.

3. Cook the Potatoes

Add the potatoes to a large pot of water with 1 tspn salt, making sure the water covers the potatoes. Bring to the boil and then reduce the heat and simmer for about 15 minutes.

The potatoes should fall apart a little when stabbed with a fork.

Once cooked, drain the water and return the potatoes to the pot.

Cook and drain potatoes
Cooking the potatoes (left) and adding drained potatoes back to the pot (right).

4. Mash the Potatoes

Here is where our method started to deviate.

Tray 1 & 2:

For the first two trays, we used a hand mixer to roughly mash with water.

We didn’t worry about trying to get the potato smooth and creamy since this will be part of the rehydation process when adding butter and milk.

Tray 3 & 4:

For the next two trays, we added the following to 6.6 lbs (3kg) of potatoes (pre-peeled weight):

  • 100g butter
  • 1 cup milk
  • 1 tspn salt
  • Chives (to taste)

Using the hand mixer we got the mashing process started, then completed it with a hand potato masher to avoid over mashing and making the potatoes gluey (which can easily happen when using an appliance).

This time we mashed until smooth and creamy and divided this mixture onto two freeze dryer trays.

Mashing potatoes
Mashing potatoes with water (left) and butter, milk, chives and salt (right).

5. Prepare Your Freeze Dryer Trays

With the potatoes mashed, it is time to add them to your freeze dryer trays.

It is good practice to record the wet weight of the food before freeze-drying – especially if you plan on rehydrating the food.

This will provide a guide as to how much liquid you will need to add back to the food to rehydrate sufficiently.

Wet and dry weight of freeze dried mashed potato
Wet weight (left) and dry weight (right) of tray 3

To do this, we place each tray on a scale, tare the weight of the tray and then add the food, recording the weight.

In this case, each tray was filled with mashed potato and smoothed out to a roughly even level to aid in uniform drying. You can check our tray weights in the rehydration section below.

Mashed potato on freeze dryer trays
Mashed potato ready on freeze dryer trays.

6. Pre-freeze the Mashed Potato

We always pre-freeze our trays of food to reduce the time in the freeze dryer.

If you have room in your deep freeze, it is a good practice to get into as it also helps to prevent food ‘explosions’ in your freeze dryer.

Because the trays were heavily loaded, we allowed 48 hrs in the deep freeze.

Mashed potato on freeze dryer tray in deep freeze
Pre-freezing in deep freeze.

7. Load the Mashed Potato into the Freeze Dryer

Next, it is time for the actual freeze-drying part!

We loaded all four trays of mashed potato into our medium Harvest Right freeze dryer – about 14 lbs (6.35kg) of potato in total.

If you are lucky enough to have a newer medium model of the Harvest Right freeze dryer, I believe you now have five tray slots but ours is an older 4-tray model.

We ran the cycle on default settings and the freeze dryer screen talks you through the process so you can’t really go wrong here (just don’t forget to shut the drain valve when instructed).

We do have our machine adjusted so our default extra dry time is 24 hours. This is so we can pick and choose when we package our food, rather than have a cycle finish in the middle of the night or work day!

Mashed potato in freeze dryer
Beginning the freeze dry cycle.

8. Check Your Mashed Potato is Completely Dry

Once the cycle is complete, it is time to check your mashed potato is completely dry. Don’t turn your machine off or set it to defrost until you are sure it is!

We have found that food is rarely completely dry when the machine says it is, so we routinely let it run for at least 6-8 extra dry hours, checking periodically and adding more time as needed.

You will know your mashed potato is completely dry when it is light, airy and slightly warm to the touch. There should be no cold spots or dampness when you touch test the food.

Our cycle ran for around 54 hrs, about 7 of which were extra dry time. Use this as a guide only, yours may take more or less time depending on the water content of the potatoes you use and the volume of food you have on your trays.

Two types of freeze dried mashed potato on trays
Completed freeze-dried mashed potato.

8. Package the Mashed Potato for Storage

Because we had different end goals in mind for each tray, once again the process here deviated a little:

Tray 1 & 3:

One tray each of water mashed potato and milk/butter mashed potato were broken into chunks and packaged into separate Mylar bags.

Packaging chunky freeze dried mashed potato
Packaging trays 1 & 3 by breaking into chunks.

Tray 2 & 4:

The remaining trays of water mashed potato and milk/butter mashed potato were powdered using a Vitamix before being packaged into separate Mylar bags. Keep in mind these were only roughly powdered to reduce packing size. The goal wasn’t to get the potatoes powdered as finely as possible.

Powdering and packing freeze dried mashed potato
Powdering and packaging trays 2 & 4.


All Trays:

We used small Harvest Right Mylar bags with a 300cc oxygen absorber in each. These were then sealed with a heat sealer.

Adding oxygen absorber and sealing Mylar bag of freeze dried mashed potato
Adding oxygen absorbers and sealing the bags.

Optional:

You can also store your mashed potato in Mason jars with an oxygen absorber if it is your preference. Just be sure to store you jars in a cool, dark place to reduce heat and light exposure (which reduces shelf life).

Both bags and jars can be vacuum sealed but Harvest Right states that this is not necessary in their ‘Guide to Freeze Drying’.

How to Rehydrate Freeze-Dried Mashed Potato

Now for the fun part – rehydrating and taste testing the results!

Mylar bags of freeze dried mashed potato
Mylar bags of different versions of freeze dried mashed potato.

Working Out the Ratio

First, here is the weight of the food in each tray before and after freeze-drying in pounds:

Wet WeightDry WeightDifferenceWeight Ratio (Dry:Wet)
Tray 14.191 lbs0.569 lbs3.622 lbs1:6
Tray 24.191 lbs0.562 lbs3.629 lbs1:6
Tray 32.879 lbs0.505 lbs2.374 lbs1:4.5
Tray 42.879 lbs0.509 lbs2.370 lbs1:4.5

And the same in kg:

Wet WeightDry WeightDifferenceWeight Ratio (Dry:Wet)
Tray 11.9 kg0.258 kg1.642 kg1:6
Tray 21.9 kg0.254 kg1.646 kg1:6
Tray 31.3 kg0.229 kg1.071 kg1:4.5
Tray 41.3 kg0.230 kg1.070 kg1:4.5

Trays 1 & 2 (potato mashed with just water):

These weights mean that approximately 86% of the weight was lost as water.

To rehydrate you will need to add 6 parts liquid (water, milk and/or butter) to every 1 part potato.

To make up a 150g serving this equates to about 21 grams of potato to 129 grams of water.

Trays 3 & 4 (potato mashed with milk, butter and chives):

Approximately 82% of the weight was lost as water.

This means to rehydrate you will need to add 4.5 parts liquid (water) to every 1 part potato.

To make up a 150 g serving this equates to about 27 grams of potato to 123 grams of water.

The Rehydration Results

I have seen people talking about rehydrating mashed potatoes at a 1:1 potato to liquid ratio, so when I worked out the above numbers I was a little perplexed.

But, my calculated ratios worked perfectly!

Here is how we reydrated and the results:

(Note: I am unlikely to be this specific about weights in the future and will instead just gradually add the liquid until it looks the right consistency).

Tray 1 (Potato, skin on, mashed with water, freeze dried and left chunky).

Rehydration Ratio: 1:6

First, the following was heated up in a saucepan (you can use a microwave if you have one)

  • 29 g butter
  • 50 g milk
  • 50 g water
  • (total of 129g liquid)

This was added to 21g chunky freeze-dried potato to make a 150g serve. After about 10-20 seconds of mixing through and another minute left sitting, the potato was rehydrated.

Result: The taste and texture was spot on. Of the four, this version was our favorite. You get the rich flavor of the peel and because quite a bit of butter and milk is used in rehdyration, the end product is very tasty.

Downside: Being chunky it takes more storage space than powdered, you also need butter and milk to have a flavorsome rehydated mashed potato (although just water would be perfectly edible).

Rehydrating Tray 1 freeze dried mashed potato - chunky
Rehydrating tray 1 – skin on, mashed with water, freeze dried and left chunky.

Tray 2 (Potato, skin on, mashed with water, freeze dried and powdered):

Rehydration Ratio: 1:6

The same volume of butter, milk, water and potato were combined as for the version above.

Result: The texture of this version was not as nice or as true to fresh mashed potato – it was slightly grainy even though the potato was rehydrated. Taste was still good but we detected less of the peel flavor because it was powdered and mixed through rather than present in chunks. This is still a very viable option if you want to reduce storage space by powdering.

Downside: Requires butter and milk for a flavorsome rehdrated product.

Rehydrating tray 2 freeze dried mashed potato - powdered
Rehydrating tray 2 – skin on, mashed with water, freeze dried and powdered.

Tray 3 (Potato, peeled, mashed with butter, chives and milk, freeze dried and left chunky):

Rehydration Ratio: 1:4.5

To rehydrate a 150g serve we added 123g of water to 27g of potato. After about 10-20 seconds of mixing through and another minute left sitting, the potato was rehydrated.

Result: Taste and texture were spot on. This version was our second favorite when it came to taste, but our favorite for convienience since all you need to rehydrate is boiling water.

Downside: Requires more room to store than the powdered version and will have a reduced shelf life compared to potato just mashed with water.

Rehydrating tray 3 freeze dried mashed potato - chunky
Rehydrating tray 3 – peeled, mashed with butter, chives and milk, freeze dried and left chunky.

Tray 4 (Potato, peeled, mashed with butter chives and milk, freeze dried & roughly powdered):

Rehydration Ratio: 1:4.5

To rehydrate a 150g serve we followed the same method as above.

Result: The taste was good but the texture was slightly gluey, probably due to powdering the potato. Although it was our least favorite of the four methods I would still recommend it if you are short on storage space and only needing hot water for rehydration appeals to you.

Downside: Texture is not as pleasant and will have a reduced shelf life compared to potato just mashed with water.

Rehydrating tray 4 freeze dried mashed potato - powdered
Rehydrating tray 4 – peeled, mashed with butter chives and milk, freeze dried & powdered.

To Recap the Results

Best Taste + Texture: Tray 1 (Potato, skin on, mashed with water, freeze dried and left chunky.) – this will be our preferred long-term storage option.

Convienience + Taste: Tray 3 (Potato, peeled, mashed with butter, chives and milk, freeze dried and left chunky.) – this will be our preferred camping & hiking option.

Space Efficient + Taste: Tray 2 (Potato, skin on, mashed with water, freeze dried and powdered).

Space Efficient + Convenient: Tray 4 ( Potato, peeled, mashed with butter chives and milk, freeze dried and powdered).

Don’t have a freeze-dryer yet and wondering if this appliance is right for you? Read my two-year, hands-on, no-holds-barred review of the Harvest Right freeze dryer here.

Mish-Mash of Results!

So there you have it, freeze-dried mashed potato four different ways!

The best method for taste in our opinion was the skin-on potato mashed with water and rehydated with butter, milk and water.

But all of them were perfectly edible so choose what works for your tastes, storage space and rehydration requirements.

Have you tried another method of freeze-drying mashed potato you think we need to know about? Let us know!

Freeze-Dried Mashed Potato Recipe

Freeze-Dried Mashed Potatoes

Try these methods of freeze-drying mashed potatoes to find the best rehydration and storage option for your needs.
Prep Time: 1 hour
Cook Time: 1 hour
Freeze-Dry Time: 2 days 6 hours
Course: Side Dish
Cuisine: American
Keyword: Gluten Free, Vegetable
Servings: 40 150g servings (when rehydrated)

Equipment

  • 1 Freeze Dryer and trays
  • 1 Breville Sous Chef (optional)
  • 1 Blender (optional for powdering)
  • 1 Mylar bags or Mason jars in sufficient quantity for storage
  • 1 Oxygen absorbers for each bag or jar
  • 1 Heat sealer

Ingredients

  • 6-8 kg potatoes adjust for your freeze dryer size

If Making Butter & Milk Mashed Version

  • 100 gram butter
  • 1 cup milk
  • 1 tspn salt
  • 1 bunch chives

Instructions

Mash Potatoes

  • Wash the potatoes and peel if desired.
  • Dice into cubes for cooking.
  • Boil until tender, drain and return to the pot.
  • Option 1: Mash with water only.
  • Option 2: Mash with butter, milk, chives and salt.

Freeze Dry

  • Spread mashed potatoes evenly onto freeze dryer trays and pre-freeze for 48 hrs.
  • Weigh each filled tray and remove the weight of the tray to get a 'wet' weight of the food.
  • Load trays into the freeze dryer and run the cycle.
  • Ensure potatoes are completely dry, they will be light, airy and slightly warm to touch.
  • Weigh each tray and remove the weight of the tray to get a 'dry' weight of the food.

Package

  • Option 1: Break into smaller pieces.
  • Option 2: Roughly powder the mashed potato using a blender – this will affect rehydration texture somewhat (see notes).
  • Package into Mylar bags or Mason jars with oxygen absorbers.

Rehydration

  • Use your wet and dry weights for each tray to work out an average rehydration ratio.
  • As a guide, our potato mashed with just water requires a 1:6 reydration ratio (1 part freeze dried potato to 6 parts liquid – water, milk & butter).
  • As a guide, our potato mashed with butter and milk required a 1:4.5 rehydration ratio (1 part freeze dried potato to 4.5 parts hot water).
  • Boil the water or heat milk, butter and water in the required quantity for your rehydration needs.
  • Add to the freeze dried potato, stirring to mix in.
  • Let rest for 1 minute after which your potato should be rehydrated.

Notes

Here are the four method variations we used:
  • Tray 1: Skin-on potatoes, mashed with water, freeze-dried and left chunky.
  • Tray 2: Skin-on potatoes, mashed with water, freeze-dried and powdered.
  • Tray 3: Peeled potatoes, mashed with butter, chives, and milk, freeze-dried and left chunky.
  • Tray 4: Peeled potatoes, mashed with butter, chives, and milk, freeze-dried and powdered.
And here were the results of the rehydration to help you choose which to make:
  • Best Taste + Texture: Tray 1 (Potato, skin on, mashed with water, freeze dried and left chunky.) – this will be our preferred long-term storage option.
  • Convienience + Taste: Tray 3 (Potato, peeled, mashed with butter, chives and milk, freeze dried and left chunky.) – this will be our preferred camping & hiking option as it only requires hot water to rehydrate.
  • Space Efficient + Taste: Tray 2 (Potato, skin on, mashed with water, freeze dried and powdered).
  • Space Efficient + Convenient: Tray 4 ( Potato, peeled, mashed with butter chives and milk, freeze dried and powdered).
Tried this recipe?Let us know how it was!
How to Freeze Dry and Rehydrate Mashed Potato
Simon Cuthbert

Simon Cuthbert

I am a passionate gardener and outdoor enthusiast who has been working on building food security through gardening since 2017. My 6 acre homestead encompasses well over 100 different fruit and nut trees. I also keep an extensive vegetable garden that keeps the freeze dryer and dehydrator running almost constantly. When not in the garden or the kitchen preserving the harvest, you will find me hanging out with my German Shepherd.