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Before you take the foods out of the dryer, it is important to test a representative sample for dryness. Take a look at this page that describes typical drying problems.
Know when your food is dry:
Some foods are more pliable when cool than warm. Foods should be pliable and leathery, or hard and brittle when sufficiently dried. Some vegetables actually shatter if hit with a hammer. At this stage, they should contain about 10 percent moisture. Because they are so dry, vegetables do not need conditioning like fruits.
Take a few cooled pieces (pick from the middle, edges, etc. You want to get samples that are fully representative of all pieces. Cut the pieces in half. There should be no visible moisture and you should not be able to squeeze any moisture from the fruit.
Fruits may remain pliable, (e.g., leathery) but they should not be sticky or tacky. They also should not be hard. If a piece is folded in half, it should not stick to itself. similarly, when a few pieces are squeezed together they should fall apart when the pressure is released. They should have a leathery or suede-like feel. High sugar fruits, like figs and cherries, may feel slightly sticky. Fruit leathers can be peeled from the plastic wrap. Dried fruits are generally eaten without being rehydrated, so they should not be dehydrated to the point of brittleness. Most fruits should have about 20 percent moisture content when correctly dried.
Berries should be dried more; until they rattle when shaken.
Vegetables are generally brittle or tough when they are dry enough. If there is a question as to whether vegetables are dry
enough, reduce the temperature and dry the product a little longer, using a low temperature toward the end of the drying period. Unlike fruits,
there is little danger of damage being done to vegetables by this extra drying time. The USDA says "Some vegetables would actually shatter if
hit with a hammer. At this stage, they should contain about 10 percent moisture. Because they are so dry, they do not need conditioning like
|Vegetables||Characteristics when properly dry|
|Beans, green||Leathery, brittle|
|Carrots||Tough to brittle|
|Corn, cut||Dry, brittle|
|Mushrooms (obviously, stick to known edible varieties only!)||Leathery|
|Peppers and pimientos||Leathery to brittle|
|Spinach and other greens (kale, chard, mustard)||Crisp|
|Hubbard squash||Tough to brittle|
|Summer squash||Leathery to brittle|
|Tomatoes, for stewing||Leathery|
|Tomatoes, sliced||Leathery to brittle|
In most cases, you want to dry fruits to 80% and vegetables to 90% of their dry weight. This sounds confusing... but for best results for both plumpness and safety, you can calculate the percent solids in the dried product to determine if the product is adequately dry. Here's how:
* 90% solids is a good value to use for vegetables. Fruits are moister if 80% is used for calculation purposes. Do not use a lower percent value for solids.
Let's say we want to dry sour cherries to 80% solids (which means 20% water).
Looking in Table 3 below, we see the solids in raw cherries are 14%
Let's say we weigh our container and find it weighs 5 oz.
And we weight the raw cherries in our container and it is 45 oz.
So, then the weight of our raw cherries is 45 - 5, which equals 40 oz.
Our desired dry weight should be:
(40 oz. times 14%) divided by 80% = 7 oz. final dry weight
Above is the
most recent version of
the Ball Blue Book