Neni has started drying her herbs for winter use. She told me she recently gathered wild thyme in the hills near her beach house on the Aegean and washed it in the sea before taking it home to dry. That’s just about as romantic a culinary notion as I’ve ever heard.
She’s drying mint, thyme, wild fennel, rosemary, marjoram, and oregano. Neni says she’s seen wild fennel growing all over Los Angeles—here’s what it looks like, via the awesome blog http://jmjamison.wordpress.com/.
The thyme, marjoram, and oregano are dried while in blossom. Drying is a simple task, with very tasty results: home dried is significantly tastier than store bought herbs, which are not always dated. Herbs lose their oomph after a year.
Here is Neni’s technique, and below, some overall tips for drying fruits and vegetables.
Cut long stems, wash them, remove any leaves with dark spots on them, tie them together with kitchen twine and hang them upside down in a room that gets air but no light. (I hang them in a pantry cabinet.) Leave them for about two weeks and they are ready. If you have enough storage space put them in large Tupperware, stalks and all, transferring about a cup of leaves (stripped of the stalks) each time to a smaller container for everyday use. If you are strapped for space separate the leaves from the stalks but in the case of mint and fennel, don’t throw the stalks away! They are very good for tea.
How Nutritious is Drying? About the same as frozen foods. However, some foods retain their nutritional content better if they are canned, like peas, but we aren’t talking about super significant differences in values.
How Does Drying Work? When you remove the moisture from foods you remove from the foods one of the things spoilers need to survive: water. In the case of fruits, 80% of the water must be removed in order to make the fruit inhospitable to spoilers. In the case of vegetables, you need to remove 90% of the water. The reason why you don’t have to remove as much water from fruits as you do vegetables is because fruits are naturally high in acid, and it is the combination of dehydration and acidity that creates a safe product. Vegetables are low acid foods, so they must be dryer than fruits in order to retard the growth of spoilers. The sweet spot for drying foods is a temperature between 95 and 140 degrees. Ninety degrees is too low, and mold and other spoilers could grow on your food during the 4 to 24 hours it takes to dry food; 145 degrees is too high: foods will cook at that temperature on the outside, but the inside of the food will still be too moist. Air circulating around the food wicks moisture away from the food.
How Do I Tell I’m At 80% or 90% Dehydration? The best method is by feel. Fruits should be leathery and somewhat pliable. Vegetables must be crisp.
What Equipment Do I Need? The best thing is to get is an electric dryer. When purchasing one, be sure is has an enclosed thermostat which ranges from 85 to 160 degrees, a fan or blower to circulate air, and trays made of plastic.
You can also dry outside. You can purchase or make drying trays for sun drying. These trays may be framed in wood but the drying surface must be nylon or plastic or even cheesecloth, not metal screen, which can throw weird tastes onto your food. If you buy outdoor drying racks, or make them, then be sure you have an insect-proof top. When drying outside, consider your region: you will need three sunny days with low humidity to dry foods outdoors. The USDA does not recommend solar collectors because they can easily cook your foods (it’s a fine line between cooking and drying in a solar collector). To reiterate: cooking the foods is a problem because while they may look dry on the outside, inside the foods are still moist enough to welcome spoilers.
If you want to use your oven the food can be laid directly on the oven racks, or a finer rack can be inserted, or you can string and hang the food in the oven. Either way set your oven to bake. Most ovens don’t go below 200 degrees, so set to 200, or whatever the lowest option is, and open the door. Or, if you have a warm feature, use that. Turn on the convection feature if you have one, to move around the air. You will need to use an oven thermometer to determine whether your oven is too hot. 140 degrees is your goal.
You can microwave small amounts of foods, but like solar collectors, it is hard to control the temperature.
How Do I Dry Fruits and Vegetables? First of all, it takes about 10 pounds of fresh food to produce 1 pound of dry food. Here are the steps.
Prep the Food. Cut into uniform pieces or slices. To make vegetable chips, slice with a mandolin.
Blanch the Food. Fruits and vegetables need to be blanched first to stop the enzymatic action. When you cut into a fruit it activates a naturally occurring enzyme that breaks down the pectin in the fruit—it’s the enzyme that causes decomposition. When you blanch the fruit—by dunking in boiling water for a minute or two—the heat deactivates the enzyme. Pat the fruit (or vegetables) dry. You don’t have to blanch the following foods: herbs, garlic, onions, peppers, and tomatoes.
Pretreat the Food. This is an optional step for fruits. Commercial operations will sulfur fruits to retain color and elasticity, but you can make a simple bath composed of Fruit Fresh (ascorbic acid) and water, or a honey dip of ½ cup of honey, ½ cup of sugar and 1 ½ cups water.
Dry the Food. Fruit should be leathery, vegetables should be crisp. Times vary. I like The National Center for Home Food Preservation online http://www.uga.edu/nchfp/, and Preserving Summer’s Bounty, published by Rodale (get the most current edition: I updated the science and can vouch for it).
Condition the Food. Place the dried food in a large jar and shake it up every day for about a week. This distributes the moisture—that 10 or 20% that remains–throughout the food.
Pasteurize the Food. This is optional, and really makes more sense for sun dryers. Pasteurizing kills any little insect larvae or eggs that might be on the food. To cold pasteurize, place the dried foods in a freezer-safe jar or vacuum-packed baggie and bring to 0 degrees for 48 hours. Then bring to room temperature and store. To heat pasteurize, place the foods in an oven safe jar and heat at 160 degrees for 30 minutes. Bring to room temperature and store.
Store the food. Place the dried food in an airtight container in a cool, dark place, like your pantry. I recommend you put up dried foods in small packages or jars because if there is any spoilage—and it only takes one under-dried apricot to get the mold going–then at least only a small percentage will spoil. In warm, humid regions like Florida it may be best to keep your dried foods in the refrigerator. Food stored at 52 degrees will last two to three times as long as dried foods stored at 70 degrees. In general, dried foods last about one year.