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SURVIVAL KITCHEN

How to Know When Dehydrated Fruit or Vegetables is Done? How Long?

Dehydrated food – dehydrating your own food is one relatively easy way to preserve some of your garden harvest. It’s also a great way to advantage when vegetables or fruits may be on Sale.

A common question when dehydrating fruit or vegetables is, “How do I know when it’s done?”

Dehydrated food is that which has been heated at low temperatures to remove most of the water content (moisture). This enables a longer shelf life. Since there is no high temperature ‘cooking’, dehydrated food preserves much of the food’s nutrients compared to some other methods.

The process of dehydrating food is fairly easy. Generally, you slice the food into pieces 1/4″ thick or thinner. Place them on the dehydrator trays. Set the temperature and timer (per recommendations for said food). And wait until they are done.

But how long to dehydrate fruit or vegetables?

Many fruits or vegetables may take as long as 12 hours (more or less, depending on a few things). With that said, here’s more of what you need to know…

Moisture Content

Generally, most professional dehydrating processes use the following percentages as a measure of being ‘done’…

Meats at about 20% moisture content or less.
Fruits about 10% moisture.
Vegetables 5%.

Residential dehydrators (compared to professional commercial dehydrators) cannot measure and control the moisture content. Therefore the only method for do-it-yourself is to periodically test the pliability of the food by hand. With experience you will learn what is ‘right’ for the various foods, fruits and vegetables.

Pliability

Fruits should be pliable (almost brittle), but not quite brittle. To test your dehydrated fruit, take a piece you have dried and cut it in half. There should be no visible moisture. If there is too much moisture remaining, you run the risk of them developing mold.

Generally speaking, fruit is considered to be sufficiently dry when, after you cut a piece of dried fruit, you cannot squeeze any water out of the piece.

Vegetables should be brittle when done.

Meats (Jerky) should be dehydrated using one of the two methods listed in the following article:
Safe Jerky In A Home Dehydrator

Moisture Test using Jar or Bag

Here’s a great trick to help know when dehydrated fruit or vegetables is done. When you think they’re done, remove some from a tray and immediately put them in a mason jar or a ziploc or sandwich bag. Close it up. If moisture develops on the glass or bag within a few minutes, then it’s not done yet.

Ceramic Bowl Test

Someone here had recommended this for vegetables and most fruits.

Throw them in a ceramic bowl; you should hear a ‘ping’.

Anyone else with examples of how to know when a given food is ‘done’ when dehydrating them yourself at home?

[ Read: NESCO Food Dehydrator | 1st Choice for Entry Level ]

[ Read: Food Dehydrator Basics ]

How to:
Dehydrate Bananas
Dehydrate Strawberries

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21 Comments

  1. I use a Corell bowl, a tempered glass product–if the food pings when I throw it in, it’s dry.

  2. First, I set my Excalibur on the kitchen scale and write down the weight of the empty dehydrater.
    Second, I load my dehydrater and again write down the weight of the veggies+scale. I actually know the weight of the dehydrater from previous use.
    Third, I subtract the two weights and that is the moist weight of the veggies.
    Finally, I turn on the dehydrater and watch the weight read-out on the scale begin to drop. When the read-out shows that 90% of the veggie weight above has been lost due to evaporation I know the veggies are ready.
    I wrote this out in long form (a lot of detail) so that the procedure is easy
    to follow. This process works for anything except the percentage loss above changes based on what food is in the dehydrater.

    1. I would think that the original moisture content would highly affect that…

      Comparing tomatoes (~95% water) vs potatoes (~80% water) for example.

      1. The original moisture content within the food does not effect the mathematics(the results) but there is one thing to watch out for. If the food has been washed it must be dried off before it is weighed in the dehydrator. Failure to dry the food before loading it in the dehydrator will result in too much residual moisture in the final product.

    2. It might be a problem if your dehydrator dries unevenly, or some of the food has more moisture than others.

    3. I wonder if I wood moisture meter could be calibrated to give an accurate reading on fruit? Has anyone tried something like that?

  3. I’m just gonna mess with you Ken, cuz that’s just the kind of guy I am. 🤪

    It’s 1/4” thick, not width.

    For the other side of me.
    Thanks for the info.

  4. I like to pat fruit and veggies dry with a paper towel before I start them in the dehydrator. Takes less time to dry. Especially strawberries and apple slices with cinnamon on them. And I dry everything ‘crisp.’ I also place them after drying in a large mason jar for a few days (with a lid). Roll them around a bit in the jar once or twice a day. This helps distribute any remaining minuscule moisture evenly throughout the pieces of food. Then pack away using your favorite method.

  5. I still use the Excalibur for tomato’s and when done put them in jars with olive oil. The rest goes into the freeze dryer, the only trouble this year is going to be the amount of product, It takes along time to freeze dry everything up to 30+ hours. Were prepping for the food shortage is winter so the old Excalibur will be humming along to. Don’t want to see the electric bill after were done.

  6. This article is perfect timing. I just ordered and received some reusable nonstick sheets for my Excalibur. I want to try to dehydrate pears for the first time. I thought using the nonstick sheets will make cleanup really easy. I have dehydrated bananas before and they stuck to the trays so badly I said never again. I’ll let you know how the sheets work.

    1. Terra, not certain, but I think I have read of folks using parchment paper or messy jobs in the dehydrator, then just chucking them…might be easy …

      1. Jane Foxe,

        I have just read that somewhere and it sounds like a really good tip. I’m going to try that. I paid $25 for 3 sheets, so parchment paper is a more reasonable approach. Thanks so much for the great suggestion. Hugs

      2. We use parchment and it works perfect. It comes in rolls of different widths 30cm, 45cm etc and you can tear/cut off lengths to suit your dryer. Not expensive.

    2. A light spritz of oil will also do the trick. But what ever way you do it a thin spatula proved helpful for me.

  7. What does it do to Fruit if one dries it completely, like a vegetable? Will it soak up moisture after drying? Or is it inedible?

    Also, will a dried item keep longer if stored in Mason Jars with an O2 absorber with it?

    Thanks for answering any of my questions.

    1. Caliche Kid
      When dried properly you must then store it in a container to prevent moisture in the air being reabsorbed into the fruit.
      When I did banana’s for our niece, after they cooled down. I placed them in a glass canning jar for consumption. Let them set 24 hours to make sure all moisture was removed. If moisture showed up inside the jar I would place the fruit back into the dehydrator for longer processing.
      When I knew the fruit was complete dry, jar test method. Then I would vacuum seal the jar closed. I did not use the 02 absorber but that was do in part the dried banana’s with her around did not last very long. To her it was like eating candy.

      If you wish a longer storage time then “yes” I would recommend the absorbers. Because you are putting a lot of time & effort into this storage item. In a glass jar vacuum sealed you can should be able to use the smaller absorber, I would believe.

  8. Caliche Kid
    Banana’s
    Discovered it is better to use NON metal utensils when working with this fruit except for slicing them. Place the fruit into a plastic bowl with water and lemon juice to keep the fruit from turning brown to black when processing.
    Same as if you were canning fruit.
    Pull the fruit out of the mix, let the fruit drain well then place on your dehydrating sheets. Part way through the drying process you may wish to flip the chips over, then continue the drying process. (you can keep using your original lemon water for your entire batch of banana’s without replacing it)

    I would take mine out do the jar test before putting them up.

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