Your outdoor gardens and your foraging are likely to produce more herbs and greens than you can use fresh daily. Even indoor plants may bear so bountifully that you can't keep up with them. To ensure a delicious variety of herb flavors year-round without wasting any of your crop, you can preserve your herbal harvest in various ways.
Here are some herbal harvest basics before you get started:
• Herb flavors are generally strongest just before the plants flower.
• Pick healthy growth and discard damaged leaves.
• Gather herbs and greens in the morning - after the dew has dried but before the sun gets hot.
• If necessary, wash and dry herbs and greens before preserving them.
My favorite way to preserve many herbs and greens is to freeze them with other foods. When winter comes, my freezer overflows with green beans and summer savory, herby tomato sauce, spinach lasagne, pesto and other good dishes already flavored with fresh-tasting herbs.
Unfortunately, summer is so short and demanding that many of us do not have time to make up complicated dishes to freeze. Start simply:
• Add a few rosemary sprigs to each corn packet, some chopped dill to broccoli or peas, marjoram and oregano to squash. Freeze some easy-to-make pesto and end-of-the-herb-garden tomato sauce. Then, if you have time, try some other recipes.
• Chives, dill, marjoram, mints, oregano, parsley and tarragon can be frozen in small packets to use as needed. Place sprigs or chopped leaves in small plastic bags or fold them into squares of plastic wrap. Seal and label them. Add whatever you need, unthawed, to the dish you are cooking. Frozen herbs become limp when they thaw, so they are not satisfactory in salads, but you can chop them into salad dressings or blend them into mayonnaise.
• Herbs and greens can be spun in the blender with water to cover, then frozen in ice-cube trays. Break out cubes, pack them in plastic bags and label. A mixture of herbs is good done this way - you can pull out as many cubes as you want to add to soup, tomato juice or sauces.
• Freeze mint or lemon balm leaves and borage or violet flowers in containers filled with water to make decorative ice cakes for punch bowls or mint tea.
• Get a head start on stuffing for the holidays by freezing a seasoning mix when everything is fresh in the garden. Chop onions and celery (or lovage) fine in the combination you like in stuffing. Add herbs to taste: parsley, sage, marjoram, savory and thyme. Freeze in small containers. Thaw and add to bread crumbs when you're ready to stuff the bird.
Dried herbs take up little space, they're convenient to have near the kitchen stove, and you may have to make do with them if you don't have a freezer or indoor herb garden. No dried herbs taste quite like fresh ones, but many have a flavor that is just as good in a different way.
In many recipes that call for fresh herbs, you can substitute dried herbs, using one-third to one-half the amount specified - use your taste to tell you how much. Dried herbs vary greatly in potency, depending on the herb itself and how long it has been stored.
It is almost impossible to determine how long dried herbs have been sitting around since they were picked. If you have a choice, frequent stores that seem to have a good turnover in herb sales. Look for dried herbs that look fresh, with good color. When in doubt, I don't hesitate to unscrew jars and sniff the aroma. And I complain to the manager when herbs are brown, smell like hay and don't have pull dates.
Do an annual spring cleaning of your herb rack, using the same look-and-sniff method you use in the store. If any herbs smell like hay, that's what they may taste like when added to food. However, there may be enough essence left to rescue for certain purposes. Empty all your stale herbs into a saucepan. Cover with water, bring to a boil, steep for a while and sniff again. If you get a good fragrance, freeze the mixture in ice-cube trays to add to vegetable soup or stews. This may sound like an indiscriminate use of herbs, but it probably won't hurt the soup, and it's better than continuing to use one decrepit herb that's too far gone to do what it's supposed to.
The major goal in drying herbs is to eliminate the moisture as quickly as possible while retaining the oils that give the leaves color and flavor. As soon as herbs are dry, strip off the leaves, keeping them as whole as possible. Save dried twigs for use in the charcoal grill or to throw in the fireplace for fragrance. Pack leaves in airtight jars and store them out of sunlight.
• Hanging long-stemmed herbs is the easiest method of drying. Gather a small bouquet, rinse only if leaves are dusty and tie the ends of the stems together. Hang them upside down in a shady place that has good air circulation. To protect them from sunlight or dust, hang the bundles inside brown paper bags punched with ventilating holes. In one or two weeks, leaves should be dry enough to remove from stalks. If the leaves can be easily crumbled, they're ready to pack in jars.
• Screen drying is suitable for small herbs, large single leaves and seed heads. Use old window screens or stretch cheesecloth over picture frames - anything that allows air to circulate freely. Place a single layer of herbs on the screen (if you place another screen on top, it makes it easy to invert the entire layer). Put herbs in a dry, shady place. Turn after a few days so they will dry evenly, which they generally will do in about a week.
• Oven drying can be an added expense, but it works. Place clean leaves in a single layer on trays in a 100-degree oven. Check them frequently and remove as soon as they are brittle. Freshly picked herbs that don't need washing can be placed in a hotter oven, about 400 degrees, with the door ajar. They will dry in 5 to 10 minutes, but you must watch them carefully to prevent burning. Herb sprigs placed between paper towels in a microwave oven will dry in 2 to 3 minutes.
• Silica gel drying is more amusing as an experiment than practical for drying a large amount of herbs. I tried it just for fun and got lovely green fresh-tasting dried parsley and chervil sprigs. Silica gel, the substance used to preserve color in dried flowers, is available at greenhouses. Follow the directions that come with it, except: don't allow edible herbs to touch the silica gel (although nontoxic, it's sandy). Put the silica in a cake tin or other sealable container. Place several layers of cheesecloth or a perforated metal rack above the silica and arrange a layer of clean herb leaves on top. Seal container tightly. Check every day and remove herbs when brittle. Most will dry in three days. One container of silica gel costs several dollars, and you can't dry many herbs at a time, but it can be used over and over if dried out as directed on the package.
Other Ways to Preserve Herbs
• Herb butters are good in any dish that uses herbs and butter - which means they have thousands of possible uses. Packed in crocks or other attractive containers, they make nice gifts. Herbs that are easily chopped by hand, such as dill and chives, can be creamed into soft butter. It's easier to spin other herb leaves or greens in the blender with melted butter, salted or unsalted, until they are finely chopped. Or use a food processor, and you needn't melt butter. In general, use about 1/2 cup roughly chopped herbs or greens to 1/2 cup butter. Add some lemon juice, a few drops of Tabasco or grated cheese for variations. Most refrigerated herb butters will stay fresh-tasting for up to a month, and they can be frozen. Add herb butters to vegetables, pairing flavor: savory butter with lima beans, tarragon butter with asparagus, sorrel butter with potatoes. Top poached eggs with spinach butter. Brush an herb butter on grilled meat, fish or hot bread. Melt it into sauces. Cream it into cheeses. You'll find herb butter disappearing so fast that it's a good idea to make up a big batch at a time.
• Herb vinegars add subtle flavor to salad dressings and sauces. I like rice-wine vinegar with dill, purple basil, tarragon, chervil and shallots, to use with delicate lettuces and greens. Cider or red-wine vinegar is fine for robust herbs such as rosemary, sage and oregano, to use for salads with pungent greens. Garlic is good in any vinegar. Try a variety of vinegars and herbs to make an interesting row on your shelf or to use as gifts. To make flavored vinegar, fill a glass jar with clean herbs. I usually just twist a handful of herbs, stems and all, to release their oils, then drop them into the vinegar. Or I mix the tough leaves and stems left over from making salads or green mayonnaise - basil, parsley, tarragon, chives or dill. For garlic or shallot vinegar, spin several whole cloves in the blender with each cup of vinegar. Let herb vinegars stand in a warm spot for a few weeks, then strain liquid into clean bottles. Fresh sprigs of herbs now can be added to the bottles to identify the vinegar and make it prettier.
• Herb mustards can be as mild or tangy as you like. Try adding fines herbes to Dijon mustard, or ground horseradish and chopped sage to lusty German mustards. Pep up bland American mustards by blending them with a handful of mixed herbs. Make your own special mustard blend: Stir enough white-wine vinegar into dry mustard to make a paste. Add a little sugar and salt to taste, then finely chopped herbs, minced garlic or shallots, grated horseradish or hot peppers. Experiment with combinations until you have the taste you like and one appropriate to the food you're serving the mustard with.
• Salt layering works on the principle that salt removes moisture from herb leaves. I dislike the use of so much salt, but it's an effective way to preserve certain herbs whose leaves are very moist or oily. If you want to try it, pour a thin layer of kosher salt in a jar, add a layer of clean dry leaves, then another layer of salt and continue alternating layers to fill jar. Press down firmly, cover and store in a dark place. Wash leaves when you remove them to use, or take their saltiness into account when you season dishes.
• Homemade herb salts are slightly to be preferred over commercial ones. Crush very dry minced herb leaves with an equal amount of salt in a mortar, or whirl them together in the blender. Spread mixture on cookie sheets and dry for an hour in a 200-degree oven.
• Herb cheeses flavored with your own fresh herbs are distinctly better than any you can buy. They're really special if you make your own cheese. Add finely chopped herbs to cream cheese, Boursault, cottage cheese or cheese spreads. Let herb cheeses stand at least several hours to develop their flavor.
• Herb jellies and syrups are made for gifts at our house, since we rarely eat sweet things. You can enhance many ordinary jellies, jams and syrups by using herb infusions as part of the liquid called for in recipes. Lemon balm is good with apple jelly, sage with cider jelly, mints with wine jelly.
Excerpted with permission from A Cook's Guide to Growing Herbs, Greens, & Aromatics (The Lyons Press) copyright 1978 by Millie Owen.