(Editor's Note: This article was originally published on September 4, 2007. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
There are several methods for preserving herbs for later use. The simplest is to use them in pasta sauces and other recipes to be frozen or canned. But when you’re baking a chicken or simmering a hearty stew, looking out the window at a monotone winter landscape, it’s wonderful to know you have a special stash of fresh tasting garden herbs waiting to add some summer sun to your meal!
Many people dry herbs over low heat in their oven or in a dehydrator (see this post). This works as long as you are careful to get the leaves completely dry before storage. However, many of the flavors of fresh herbs can be lost in the drying process, especially under home conditions.
I prefer to freeze herbs, adding oil to protect their flavor during storage. I don’t use pesticides in my herb garden, so I don’t wash the leaves – but I do check them for hitchhiking bugs! Strip the fresh leaves from the stem, and stuff them into a food processor. Process leaves to a rough paste, just as if you were making pesto (see the previous article in this series). Add enough olive oil so the herb bits look shiny and slightly damp (about a tablespoon per loosely packed cup of un-minced leaves).
I freeze minced herbs in ice cube trays, just as I do for pesto. Basil goes into regular trays, while intensely flavored herbs like rosemary or lemon thyme get frozen in mini-cubes. Pop the cubes out into freezer bags, and they will keep for at least a year. The taste is nearly the same as freshly minced herbs and far better than dried, store bought herbs. If you measure the herbs before processing and count cubes, a little math will let you mark your bags. For example, if 2 cups of basil leaves yield 8 frozen cubes, your label would say, “1 cube = ¼ cup fresh basil leaves.”
You can freeze combinations of herbs, just as you’ll use them in your recipes. Other ingredients can be added to the herbs as you process them. Thai basil, ginger, garlic, and Thai chili peppers are a great combination for stir fry. I freeze vast quantities of herbs for spaghetti sauce according to my mother-in-law’s recipe (4 parts basil, 2 parts oregano, 1 part thyme). Thyme, rosemary, garlic, and orange zest make a nice combination for marinating pork, especially when combined with red wine vinegar and a little olive oil after thawing.
Most of my recipes use minced herbs, but if you want to freeze whole leaves, try tossing them with a little olive oil as suggested recently in this post. Some people simply put clean, dry herb leaves into freezer bags and take out whatever amount they need for a recipe. An Italian friend taught me that thyme leaves are easy to strip from their stems if you freeze a bunch of thyme in a plastic bag. Once frozen, the leaves drop right off! I freeze fresh thyme even when I plan to use it immediately, just because it’s so tedious to strip the leaves by hand.
Another wonderful way to preserve the flavor of garden-fresh herbs is to make herbal vinegars. Simply stuff a selection of herbs (stems and all!) into a clean glass jar or bottle, and fill to the top with vinegar . Let the herbs steep in a cool, dark place for 2 or 3 weeks. When you like the flavor of the vinegar, strain it to remove the herbs, and pour it into a clean bottle. You can add a couple of herb sprigs to make it look pretty, but most of the flavoring of the vinegar should be done in the first weeks.
You can use various types of vinegar to add different flavor notes, but I'd avoid the harshness of distilled white vinegar. White wine vinegar is a good choice, as its flavor is so mild. Greek oregano is wonderful in balsamic vinegar, and Italian herbs might be even nicer in red wine vinegar. For extra zing, add a clove or two of garlic, a few whole peppercorns, some strips of lemon zest, or a small hot pepper.
If you have some beautiful purple basil, now is the time to put it to use. A few sprigs will turn white wine vinegar a lovely shade of rosy-pink. Pretty bottles and decanters will show off your tasty, decorative selection of herb vinegars. Your winter salads will never be sprightlier!
The Herbs Forum is a great place for subscribers to ask questions, share suggestions, and swap everything from seeds to recipe ideas, so please drop in!
Pinch your herbs with abandon, add a few fresh leaves to every meal, and enjoy your harvest all winter long.
Whether you have an extensive formal herb garden or a few herbs in a pot by your back door, I hope you’ll get the most from your herbs this summer!