Dave Freer asked me to talk a little about dehydrating – so here it is.
Dehydrating is one of my favourite ways of preserving the harvest for several reasons: it preserves most of the nutritional content (often destroyed in heated means of preserving, like bottling), you need add no sugar or vinegar (again, like bottling, or canning), it is chemical free (unlike many commercial products), and it requires no electricity to keep it (like freezing). I love dried fruits, and always try to get in bulk fruit in season and do great batches of apples, peaches and cantaloupe, my favourite fruits.
Apart from fruits I dehydrate most of my excess vegetable harvest, carrots, zucchini, onion (sometimes), tomatoes, potato, capsicums, chilli, whatever I have left over and would like to keep. You can reconstitute them by soaking them in water, or just chuck them into casseroles and stews and soups as they are. You can keep cubes of dehydrated vegies as soup stock (just add water), or instant soups.
There are some vegetables that are best left to dry naturally – bush beans and peas being the principle ones. These I generally leave to dry on the bush/vine, or pick once the pod is drying out and leave them in the greenhouse. If you do them in a dehydrator they tend to lose colour.
The kind of dehydrator you buy is important. You need a model that will give you an adjustable drying temperature – because it is far, far better to dehydrate at 42 C or lower (a cool temperature) than to destroy the nutrients in the food at 80 C or above (which is where most fixed temperature dehydrators are set). At that temperature you are virtually cooking them. If you dehydrate at the lower tempt (42 C or lower) then you preserve most of the nutrients. It may take longer, but you get better food with a brighter colour than if you fry it at above 42 C.
You should also consider how much food you want to dehydrate. My dehydrator (an Ezidri Ultra FD1000) expands to 30 trays – and I can be using all of those trays often. A single large pumpkin can take up those 30 trays.
Some people use salt to help dehydrate their vegies – I don’t at all. I may sometimes add herbs, but not salt.
You can prevent pale fruits (like apples) from discolouring in the dehydrating process by give them a brief soak in water with added lemon juice or citric acid (I use either – maybe a couple of lemons’ worth of juice to a 5 litre bowl or a couple of tablespoons of citric acid). All fruits will discolour a little when dehydrating, but I find this keeps apples to a deep cream. Don’t worry about discolouration – it doesn’t spoil the food, and is better than the bleaching processes of commercial dried fruits and vegies.
Storing the dried foods – I always use airtight glass jars, either very clean and dry or I sterilise them in the oven for 30 minutes (wash jars in hot water, place in oven on a towel at about 110 C for about 30 minutes – they will dry and sterilise). Make sure the lids are clean and dry as well. Sometimes I use moisture absorbers – I started this last year as an experiment – half of my apple jars had moisture absorbers in them, the other half didn’t, and all fruit kept equally as well.
Overall I love dehydrating – it is quick and simple, and is an excellent way to keep the harvest – retains nutrition, you add no chemicals (unlike many commercial products), and you don’t need electricity to store it.