Preservation 101: Drying and Dehydration | Skillshare Projects

Scott Owens

Physicist, Programmer, Brewer, Preserver



Preservation 101: Drying and Dehydration

This class is intended to be the first in a longer series, each looking at individual techniques used in food preservation. This first one is one of the simplest, dryaing and dehydration.
Its broken down into four core units:

  • Theory explaining the practical approaches
  • Demonstration of the basic technique
  • More indepth and complete theory and explaination of advanced techniques
  • Demonstration of an inbetween technique that requires specialised (but available) equipment

Which translates into the following class outline:

Video 1: Intro

  • Introduction to the course
  • What will be covered

Video 2:  Basic Theory

  • Why drying?
  • Removing moisture to prevent microbial growth
  • Drying methods:
  •     Air drying
  •     Gentle heat
  • Drying tools and approaches:
  •     Air drying rack
  •     Ovens (talk about temperatures and airflow)
  •     Dehydrators

Video 3: Demonstration 1

  • Oven dried tomato's

Video4: Advanced Theory

  • What to dry how:
  •     Most fruit and vegetables should be dried with gentle heat
  •         Most have a lot of moisture and a dense structure, will go mouldy before they dry sufficiently
  •     Beans and similar things with a hard fibrous outer layer, and herbs air dry well
  •         Usually lower moisture content, or designed to resist mould.
  • Kicking air drying up with Desiccation
  •     Why: when volatile oils are involved gentle heat can ruin a crop, but air drying can sometimes be to slow to protect the crop
  •     Explanation of technique
  • Freeze Drying
  •     Basic principles of operation
  •     Explanation of simplest home technique

Video 5: Demonstration 2

  • Dehydrator dried fruit (apples and strawberries)

Video 6: Storage and closing remarks

  • Information about storing for different periods of time
  • Introduction to the project

which in the provided template comes out as the following outline:

The dificult part was to decide on a project for the class, I decided to go simple with the project itself, but in the video content encourage the students to go ambitious with their project, and back this up with a more complex demonstration project


Don’t bring the burn: dehydrate your own goods and show us the tasty results

After some consideration I wrote a class description that targets both the reason for writing this class, as well as describing what the students will do through it:

Preserving food was a critical technique for human survival and population growth through much of our history. However, today these techniques are often overlooked as they are not critical to our food security. This ignores one of the most important aspects of these techniques, they often make interesting new or more concentrated flavours when they are made.

This class is the first in a larger series exploring the different techniques in food preservation and how you can use them to make new tasty treats to enjoy. Starting here, with what is arguably one of the simplest techniques, drying and dehydration of fruits and vegetables.

We will cover the different common home drying techniques, as well as talk about some of the more advanced techniques used in industrial settings, and how to apply them at home.

Finally culminating in an opportunity for you to make some dried tasty treats of your own.


When writing the class description I also worked on a project description that would better express what I would like the students to attempt, and came up with this:

Now that you’ve seen some of the basics and we have discussed some of your other options when dehydrating fruits and vegetables. Why don’t you test things out.

Find a fruit or vegetable you think would be interesting to dry out,  the weirder the better, then let us know what your going to make, and what techniques your planning to use.

Test out your idea and get back to us, show us your setup, what the results were, and how it tasted, good or bad, and we can all try and find new tasty combinations, and help each other make even better things next time.

Keep us updated on your attempts, let us know if your try anything new or different.

Better yet, tell us how you’ve then gone on to use your dehydrated goodies, whether just as snacks on their own, or used them in a larger recipe to add a punch of flavour, or to overcome issues with too much liquid.

Lastly I have been working on editing together a introduction video for the class, due to limited processor time right now I have rendered a lower quality version to check that everything stitches together well, then uploaded it for you to view.

The final cut will have a much higher visual and auditory fidelity, I was just pushed for time and didnt want to wait for a full quality render on a test version.

And finally If this course is of interest to you, you can find it here

There are a few elements of it Im still not happy with but I dont know editing particularly well, Ill be visiting a friend who specialises in editing in a week or so, and they have agreed to help me fix the errors that are really bothering me, and to add an animation to help explain the graph in theory module 2. So some small tweaks to come.


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