Deconstructing Dehydration

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One of the oldest forms of food preservation, dehydration has been a part of the human diet since the birth of civilization. Before refrigeration and other modern forms of preserving food, It was a necessity to make a large hunt or harvest last longer than one sitting. Food scarcity is even a life or death issue in today’s world, so every method is used to prevent food waste. The dehydration process removes water from food that would be an ideal environment for foodborne pathogens to grow. 

Historically, the first dehydrators were the sun and outdoor fires where meat would be hung and dried. The modern dehydrator can be as simple as a mesh basket that is left in the sun to a convection heated box with a temperature dial and timer. The primary advantage of a modern dryer is that it isn’t weather dependent (a cloudy or rainy day can stop the dehydration process cold). As long as you have a box or container made out of food safe materials and a heating element, you can dehydrate at home (DIY or store bought). The diversity of what can be dehydrated is only limited by the imagination of the person prepping. 

Fruits and vegetables are extremely common for dehydration and lean proteins can even be turned into delicious jerky that keeps for ages. There are a few rules of thumb to use when trying to select the best pieces of produce to dehydrate. For fruits, it is best to choose something that is at peak ripeness and heavy for its size. Vegetables should be dehydrated as close to harvest date as possible to ensure freshness and that fiberouse (overripe) flavors are not present. When selecting the perfect piece of protein for dehydration, choose any cut that is lean (fat does not dehydrate and will spoil so trim away what you need to) and cut to a ¼ in thickness. 

Anyone who has sliced an apple and let any time elapse knows that a rapid change in coloration (browning) due to oxidation can occur. So how do dried fruit producers keep their dehydrated fruit and produce at peak quality both before and after dehydration? Pretreatment of fruits and vegetables are what halt this process and allow your dehydrated product to retain its crisp color and flavor. Fruits can undergo several different treatments to help retain its color,  an ascorbic acid bath (1.5g per quart of water), citric acid bath (1.5g per quart of water), honey bath (1:4 honey to water ratio), and a sugar syrup blanch (1:2 ratio sugar to water). All fruit can be pretreated with any of these methods and have a product that is better suited for dehydration. Vegetables are usually treated with a steam or water blanching that is effective at stopping enzymatic browning. 

Fruit leather is a fun and easy treat that can be made in the dehydrator with fruit that may be bruised or not visually appealing. Pureeing 250g of any variety of fruit mixed with a tablespoon of lemon juice and 100g of Ultra Stick (corn syrup solids) will produce a fruity puree that can be spread to ¼ in thickness and dehydrated for 4 hours at 135°F. 

It’s important to understand that treating protein that is going to be made into jerky is the only way that it will be safe for consumption. Meat should be treated so that it’s brought to a temperature that will kill food borne pathogens, this can be done either before or after dehydration, and is contingent on this to ensure preservation. Pretreating jerky involves bringing your desired marinade to a simmer and dipping strips of meat into the solution for 2mins to heat and essentially cook each piece, and is safe to eat after dehydration. Post-treatment involves simply placing your dehydrated jerky into a preheated oven at 265°F for 10 min or until an internal temp of 160 is reached. Alternatively using a 5% acid bath (all vinegars state their percentage of acidity on the bottle) for 10 min will kill any present bacteria before dehydration and doesn’t need to be heated to be safe to consume (*note, this method is not recommended for game meats due to their higher risk of parasites). 

When your jerky is finished dehydrating, a test for dryness can be performed by bending a slice of jerky, which should bend and snap slightly like a green stem of a tree. If using a water activity meter, a reading between 0.7-0.8 is considered a preserved jerky that is safe to eat. Too dry and it would be unpleasant to eat and too moist would be prolific in the spread of bacteria. 

The dehydration process is basic and a method as old as human civilization. It can produce sweet or savory products that can be enjoyed well after they are prepared and can decrease food scarcity when carried out properly.

TypePrep(*Pre)Treatment Dehydration
FruitCut ¼ in pieces*Ascorbic acid bath (1.5g Ascorbic acid to 1qt of water) 5min
*Citric acid bath (1.5g citric acid to 1qt water) 5min
*Syrup blanch(1 part sugar 2 parts water simmering) 5min
*Honey bath (1 part honey 4 parts water) 5min
@ 130°-145°F(6-36 hrs depending on fruit type).
-Apple 6-12 hrs
-Banana 8-12 hrs
-Cherries 24-36 hrs
-Grapes 12-20 hrs
-Peaches 24-36 hrs
-Pineapple 24-36 hrs
-Strawberries 6
-12 hrs
Vegetable Cut ¼ – ½ in pieces *Water or *steam blanch until vegetables are tender but still retain some snap. Should not be fully cooked.6-18 hrs depending on cut of veg and elevation
-Beets 10-12 hrs
-Carrots 10-12 hrs
-Tomatoes 10-18 hrs
Meat Jerky Slice ⅛ – ¼ in strips*Vinegar soak (soak meat for 10min in 5%acid before marinading for 24 hrs), *Precook (simmer marinade solution and dip each strip for 2 mins reach internal temp of 160°F) Post heating (Place dehydrated strips into oven @ 265°F for 10 min)~6 hrs @ 155°F
  • Drying times are guidelines only, monitor dryness and end or extend if needed.