We’ll take a break from this instructional series tomorrow before returning for a few more posts on the fundamentals of dehydrating food. Feel free to add additional questions to the comments below and we’ll try to add them to this series of key dehydrating concepts.
The question of temperature comes in many different forms. Know that some dehydrators don’t have a thermostat, some people want touse their ovens (understandable if that’s what you have) and others are wondering what temperature to set the dial for their dehydrator on. We’re going to assume, for this article, that you have the ability to change your temperature and are using a dehydrator.
If you are using an oven, the same knowledge applies (the difficulty being that many ovens don’t drop below 200 degrees which is hot enough to cook your product without drying it). We’ll have a separate post later in the week (or next) to discuss oven drying.
Dehydrators with a variable temperature setting offer so much flexibility to the home preserver. Namely:
- They allow you to dehydrate things hotter than most fixed temperature units which allow you to dry things like jerky without needing to finish in the oven at a higher temperature.
- They allow you to dehydrate things cooler than most fixed temperature units which allows you to dry things like herbs without turning them brown and losing their flavor.
- They allow you to precisely dry food below 105-158 degrees (more on this key temperature in a moment).
Many people don’t understand the thermostat on their dehydrator (I didn’t for a long time). The temperature on the dial generally (always in the case of the Excalibur line of dehydrator that we use) refers to the temperature of the FOOD and not the air inside the box. It is, of course, an approximation but it’s very different from the setting on your oven which refers to the ambient temperature of the air around your food. The air temperature is generally 20 degrees warmer than your product while dehydration is happening (the process of evaporation will lead to cooler food temperature).
Another consideration is that the natural enzymes in food (these are good for you) are destroyed with a certain amount of heat. I’m certainly not an expert in the field of RAW food but understand this to be a core component of the diet (there’s a great FAQ here) which describe the benefits of raw food.
Key concepts involved in cooking food under very hot temperatures:
- Too much heat kills healthy enzymes in food
- Destroys vitamins
- Changes the pH level of food
The actual temperature at which this happens is still debated. Some claim:
- Enzymes die when food temperature raises higher than 105 degrees
- Enzymes die when food temperature raises over 120 degrees
- Enzymes will die when food reaches more than 140-158 degrees in a wet state
- Enzymes are much more resilient when food is in a dry state
The ability to use a thermostat is a significant advantage if you’re trying to preserve much of the nutritional benefits from your dried foods. I can’t tell you which of the four contradicting statements above are correct but will point you to this article from Excalibur which details their research and names scientific sources they have used to reach their conclusions (and the ones I follow). This isn’t about safety – it’s simply about preserving as much of the ‘goodness’ that you can.
Having said all of that, here’s some rough guides for dehydrating different things and the food temperatures I use:
Pasta 135 Degrees
Fruit 135-145 degrees
Vegetables 125-135 degrees
Herbs 95-100 degrees
These are rough guides and many recipes will call for starting at one temperature and then reducing as the process goes on. The key is to understand the advantages of varying your temperature and to know that there is a point when heat can kill much of the benefits of the produce you are working with (though it will still be safe and tasty).
This is part of a series of posts dedicated to the fundamentals of dehydrating and sharing tips that will ensure success as well as traps to avoid. Make sure to check out the comments as they add to the discussion. Additional information can be found through some of our posts on dehydrating or in our Facebook Group where a vibrant community with plenty of discussion can often be found!