I’ve built my career promoting fresh herbs for cooking, so when people ask me how to preserve them, I often say I don’t—I cook with whatever fresh, seasonal herbs I have in my garden. (In Seattle’s mild coastal climate, we can harvest at least a handful of herbs year-round).
But I admit that’s not the whole truth. If you grow herbs, you know that flush feeling at summer’s end, when plants are lush and waist-high. You can’t avoid thinking how sad it will be to lose the abundance to the inevitable frost. So although I don’t obsess about saving each and every sprig, I do preserve herbs in many ways: I hang bunches of lavender for shortbreads and spice rubs; dry mint for teas; save oregano for winter tomato sauce; and grind lemon verbena with sugar for drinks and custards. I sieve and bottle fennel "pollen" for seafood dishes and I bottle capers made from nasturtium seed pods. And of course I couldn’t make it through a winter without a freezer filled with pesto made from the late bonanza of fresh basil.
Easy Does It Drying
Drying is the easiest way to preserve herbs, but there are both good and poor herbal candidates for drying. Ever try cooking with dried parsley, cilantro or tarragon? Not so good! The best herbs for drying are members of the mint family (labiates), including spearmint, oregano, thyme, rosemary, sage, savory and lavender. One exception is basil--its complex flavor is best captured by freezing. (For tips on harvesting and preserving specific herbs, see "Gathering Goodness.")
Because essential oils evaporate, the flavor of dried herbs always differs from fresh flavor. But dried herbs can be used successfully in soups, stews, braises, breads, rubs and marinades. In fact, some authentic Mediterranean recipes require dried herbs; lamb tangine, for instance, relies on the intense flavor of dried mint.
The simplest way to dry herbs is to tie a bunch of sprigs together with a piece of string and hang them in a warm, dry place, out of direct sunlight. Remove the dried leaves from the stems and store them in a tightly sealed container, away from bright light.
When to Freeze
Freezing is the most effective method for preserving essential oils, so it’s the best choice for delicate, soft-leaved herbs, such as basil, tarragon, dill and marjoram. You can simply flash-freeze leaves on a baking sheet, then gather and store them in a bag. But a better way to capture the herbs’ flavor is to immerse them in vegetable oil or butter. This not only traps their flavor, but also protects the leaves from freezer burn.
To use oil, simply mix a bit of it with chopped herbs to coat them, then freeze the mixture in small, tightly sealed containers or freezer bags. Olive oil complements most herbs, but for a more pure herb flavor, choose a neutral-tasting oil, such as grapeseed. For a large harvest, use a food processor. Fill the work bowl with herb leaves, start the motor and pour in enough oil to form a thick paste, like a pesto.
For traditional pesto, use olive oil and nuts, garlic and grated Parmesan cheese. While basil and pine nuts are most commonly used, feel free to use any soft-leaved herb and any type of nut you like.
To make herb butter, blend softened butter with herbs in a food processor, then freeze the blend as logs. Then, slice only as much butter as you need—right from the freezer.
Some herbs, such as lemon verbena, rose geranium and lavender buds, can be preserved with sugar. Process equal parts of the herb and sugar in a food processor until you have a moist powder. Freeze the sugar in resealable bags and use it to flavor baked goods, syrups or custards.
Here are a few of my favorite recipes to hold onto the herbal harvest through fall and winter—until you can enjoy fresh garden flavors again next spring.
Makes 1 cup
Nasturtiums form seeds late in the season, and you have to hunt beneath the leaves to find them. Be sure to harvest young seed pods that are still green and soft. When they yellow, the seeds become too hard for this recipe.
3 tablespoons kosher salt
2 cups warm water
1 cup nasturtium seed pods
2 bay leaves
Small bunch thyme
1 cup white wine vinegar
1 tablespoon sugar
Dissolve salt in water, pour over seed pods and let soak at room temperature for 2 days.
Drain and rinse seed pods. Put them in a clean glass pint jar along with bay and thyme.
Bring vinegar and sugar to a simmer and pour over seed pods. Cover and refrigerate for at least 3 days before using. Store capers in the refrigerator for up to 3 months.
Makes 3 cups
This is the best thing you can put on a turkey sandwich!
¼ cup dry mustard powder
1 cup whole yellow mustard seed
1 cup coarsely chopped dried apricots
1 cup warm water
1¼ cups cider vinegar
1½ tablespoons kosher salt
¾ cup coarsely chopped dill leaves
Mix together mustard powder, mustard seed, apricots, water and vinegar in a mixing bowl. Cover and let sit at least 2 hours or overnight.
Transfer mustard to a food processor. Add salt and dill. Process until seeds begin to break down and mustard becomes spreadable. (Some seeds will remain whole.) Store in tightly sealed jars in the refrigerator up to 1 month; or freeze for longer storage.
Makes 1¼ cups
This vibrant Italian sauce is terrific on grilled or broiled fish.
- 1½ cups flat-leaf parsley leaves, gently packed
- ½ cup spearmint leaves, gently packed
- ½ cup roughly chopped chives
- 1 clove garlic
- 3 anchovy fillets (optional)
- 2 tablespoons capers, rinsed
- Zest of ½ lemon
- ½ teaspoon kosher salt
- ½ cup extra virgin olive oil
- Process all ingredients except oil in a food processor until finely chopped. Scrape down sides.
- With machine running, add oil in a slow, steady stream. If not using within 2 days, store in small freezer bags in the freezer.
Makes 2 pounds
Angelica stems that are home-preserved in sugar are a wonderful treat to eat like candy. You also can chop and sprinkle the candied stems over ice cream or add them to pound cake. Harvest young, bright-green tender stems for this recipe.
- 1 pound angelica stems, cut in 4-inch sections
- 3 cups sugar
- Bring a large pot of water to a boil. Add cut sections of angelica stems and boil 10 minutes.
- Drain and toss with 2 cups of the sugar in a shallow baking dish. Cover with plastic wrap.
- The next day, the sugar will have become syrupy. Scrape angelica and syrup into a heavy-bottomed saucepan. Boil until syrup reaches 235 degrees on a candy thermometer.
- Spread remaining 1 cup sugar on a plate. One by one, lift a piece of angelica with tongs, roll it in sugar, and place on a parchment-lined rack. Continue to roll all the stems in sugar.
- Allow angelica to dry one or two days, turning it once. Store in a tightly sealed container.
Jerry Traunfeld, author of The Herbal Kitchen (William Morrow, 2005) and The Herbfarm Cookbook (Scribner, 2000), won a James Beard Award for Best Chef/Northwest. His new Seattle restaurant, Poppy, will open in September.