Herbs: Using and Preserving

Mint growing outside

Background  Herbs and spices play an important role in the cuisine of many cultures and consumer demand in the U.S. for spicy and flavorful foods continues to increase. The leaves and seeds of herbaceous plants used to season foods have become known as herbs while spices are berries, seeds, flower buds, roots, or bark of tropical plants. These savory ingredients can be used as healthier alternatives to replace or reduce the amount of salt and sugar in foods. Herbs are often grown in home gardens or purchased fresh and used to enhance food dishes and flavor beverages, vinegars, and oils. Fresh herbs can also be dried or frozen for later use. Their flavor comes from specialized aromatic oils in the cells of the plants. Chopping or grinding breaks the cell walls and releases the flavor; heat increases the rate at which some herbs release their flavors.


Quantity of Herbs to Use
 

Herbs are used to complement, not disguise, the flavor of food
For soups, sauces, or meat dishes:
1/4 teaspoon of dried herbs per four servings is usually adequate.
The flavor of dried herbs is about three to four times stronger than fresh herbs; 
to substitute dried herbs for fresh in a recipe, use 1/4 to 1/3 as much.
 
1/4 teaspoon dried and
powdered herbs
= 1 teaspoon dried whole
or crumbled herbs
= 1 tablespoon fresh
chopped herbs

 Chopping leaves finely will create more cut surface and 
allow additional flavor components to be released.
Seasoning suggestions. These herbs, spices, and other seasonings may serve as alternatives to salt. Suggested seasonings are not intended to all be used together; experiment with mixing different herbs to suit your preferences. Modified from NIH 2013.
Food Herbs and other seasonings to enhance flavor
Meat  
Beef Bay leaf, marjoram, nutmeg, onion, pepper, sage, thyme
Lamb Basil, curry powder, garlic, mint, rosemary
Pork Garlic, onion, oregano, pepper, sage
Chicken Marjoram, oregano, parsley, rosemary, saffron, sage, tarragon, thyme
Fish Basil, chervil, chives, dill, marjoram, dry mustard, paprika, parsley 
Vegetables  
Carrots Cinnamon, cloves, marjoram, nutmeg, rosemary, sage
Corn Cilantro, cumin, curry powder, paprika, parsley, onion
Green Beans Curry powder, dill, lemon juice, marjoram, oregano, tarragon, thyme
Leafy Greens Onion, red pepper
Peas Ginger, marjoram, mint, onion, parsley, sage, ginger
Potatoes Bay leaves, chives, dill, paprika, parsley, sage,  garlic, onion
Summer Squash Marjoram, rosemary, sage, cloves, curry powder, nutmeg
Winter Squash Cinnamon, ginger, nutmeg, onion
Tomatoes Basil, bay leaf, chives, dill, marjoram, oregano, parsley, pepper
Eggs Basil, chives, chervil, dill, marjoram, parsley, paprika (hard cooked eggs), tarragon
Yogurt Basil, chives, lemon thyme, marjoram, mint, sage
Butter Chives, dill, garlic, mint, parsley

Washing Herbs Fresh basil, cilantro, parsley, chives, rosemary, and many herb seedlings are often available at Colorado markets. Whether fresh herbs are grown in the garden or purchased, damaged leaves should be removed and the herbs should be thoroughly washed before using. Sturdy herbs, such as rosemary and thyme, can be rinsed well under cool running water but delicate or fine-leaved herbs, such as basil, dill, or tarragon, should be submerged in a bowl of cool water and swished back and forth. Shake gently or use a salad spinner to remove excess water and dry with paper towels.

Herbal Infusions Infusions, which involve steeping fresh herbs with desired flavors or characteristics in water or oil, are used to flavor drinks, such as teas and cocktails, and foods, such as salad dressing, butter, yogurt, vinegar, and oil. To become familiar with the flavor of an herb, mix it with butter or cream cheese, let stand for half an hour, then taste this mixture on a cracker.


Can homemade pesto be canned?


Pesto, a spicy green paste well known for flavoring pasta dishes, is an uncooked seasoning mixture of herbs, often including fresh basil, garlic, olive oil, pine nuts, and cheese. It may be stored frozen but there are no home canning recommendations. Prepared pesto may be frozen in small freezer containers or in ice cube trays (2 tablespoons per cube). Another option is to freeze in a square pan, covered with plastic wrap. When completely frozen, cut into cubes and transfer to a resealable plastic freezer bag. Frozen pesto will store for up to 6 months. Thaw pesto cubes for 15 minutes at room temperature or at 30-second intervals in a microwave oven until soft. Mash with a fork before using in recipes.

How and When to Use Herbs The way herbs are prepared and used can vary widely and this influences their culinary use.

  • For best flavor results, add dried herbs near the beginning of the cooking process to provide sufficient time for the herbs to rehydrate.
  • Fresh herbs are usually added during the last part of cooking.
  • Wrapping whole herbs in a cheesecloth bag before adding them to cooked dishes makes removal easy before serving.
  • Herbs in uncooked foods, such as salad dressings, dips and fruit mixes, need time to blend flavors, so add them as far in advance of serving as possible.
  • Basil, cilantro, dill, mint, oregano, parsley, rosemary, sage, savory, tarragon, and thyme add interest to salads and rosemary, thyme, or basil may be added as a secondary flavor to sorbet or summer beverages. Some herbs are best used fresh, such as burnet, chervil, and parsley, because they have little flavor once dried or frozen.

Herb Flavored Vinegars and Oils Herbs may be added to vinegar or oil and used in the seasoning of salads and sauces. It is important to store homemade herb infused oils in the refrigerator and use within four days because they have the potential to support the growth of Clostridium botulinum bacteria. Commercially made herb/oil mixtures are often stored at room temperature but this is because of special processing or acidification steps, always check the label before storing. For more information on preparing and using herb flavored vinegars and oils, please see CSU Extension Fact Sheet #9.340, Flavored Vinegars and Oils.

Herbal Teas and Beverages Traditionally, a true tea is made from the leaves of the tea plant, Camellia sinensis. Beverages made from the leaves, flowers, bark, or roots of other plants have become widely known as herbal teas. Herbal teas do not go through the same curing process as black or green tea so it is important to brew herbal teas using water that has been heated to a temperature high enough to destroy harmful microorganisms. It is recommended to brew herbal teas at 180-200°F for 5-15 minutes. Brewed herbal tea can be chilled for use as iced tea. Herbs or herbal teas should not be used in making tea which is not brewed, such as sun tea; however, after cooling, brewed herbal tea can be added to sun tea that has been made with black tea labeled for cold brewing use.

Flavor characteristics of common culinary herbs (Modified from Univ. of Delaware, 2012).

Flavor Herbs Characteristics
Delicate Burnet, chervil, chives, parsley May be used in fairly large quantities; combines well with most other herbs
Medium Basil, celery leaves, tarragon, marjoram, mint, oregano, savory, thyme Use in moderate amounts (1-2 teaspoons dried herbs for 6 servings)
Strong Bay leaf, rosemary, sage Will impart a dominant flavor
Sweet Fennel, mint Gives a cool burst of flavor to meat, seafood, and  sweet dishes
Savory Oregano, tarragon, chives, dill Often used to flavor meat, egg, and cheese dishes

Food dehydrator Drying herbs with a commercial food dehydrator typically allows for better control of temperature within the recommended temperature range. Arrange herbs on drying trays in single layers; good air circulation between trays is important. The National Center for Home Food Preservation recommends pre-heating the dehydrator with the thermostat set to 95 ° F to 115 ° F. In areas with higher humidity, temperatures of 125° F may be required. Check your dehydrator instruction booklet for specific details. For information on dehydration methods, please see CSU Extension Fact Sheet #9.308, Drying Vegetables and #9.309, Drying Fruits.

Gas or electric oven. Most ovens cannot be set at low enough temperatures for drying herbs but the oven light of an electric range or the pilot light of a gas range may furnish enough heat for overnight drying of herbs. Place single layer of herbs on oven-safe trays.

Microwave oven Drying in a microwave oven can be a good option for small amounts of herbs and appears to be the best drying method for reducing microbial contamination of herb leaves. Check the microwave oven owner’s manual for specific herb drying directions. Make sure herbs are thoroughly dry before placing in the microwave oven so that residual water does not cause the herbs to cook instead of dry. To dry, place a single layer of herbs between two paper towels on a microwave-safe plate. Avoid using paper towels made from recycled materials as they may contain metal particles which could cause sparking in the microwave oven. Place a 1/2 cup of water in 1 cup measure next to plate of herbs.

For microwave oven drying ½-1 cup herbs on a high setting
Microwave oven wattage 500-600 watts 650-750 watts 750-1200 watts
Approximate drying time 3-6 minutes 2-4 minutes 1-2 minutes

Some herbs, such as basil, should be dried on a low microwave oven low setting. It is important to stop every 15 seconds to check the herbs and periodically turn them over. Although some microwave drying instructions suggest a longer time, in Colorado’s dry climate, it is necessary to check every 15 seconds to reduce the risk of fire and charring of the herbs.

Air drying Air drying is the least expensive method but offers the least amount of consistency in drying and the greatest opportunity for contamination with bacteria or dust. Tie two to three sprigs of fresh herbs at the base of stems with twine and hang away from direct sunlight at room temperature or lay on cheesecloth stretched on frames or netting screens. This method may be used for sturdier herbs. More tender leaf herbs, such as basil, tarragon, lemon balm, and mint, are higher in moisture and should be dried quickly to prevent mold growth using one of the previous methods.

Storing dried herbs Dried herbs should be stored in a cool, dry place and most will keep well for up to a year. Their strength can be judged by their aroma. Dried herbs can be stored whole or crushed, but whole herbs retain their flavor longer. To ensure optimum quality, store in rigid, opaque containers with airtight seals. Choose ceramic jars or darkened glass containers to help protect the herbs against light deterioration. Make sure herb leaves are completely dry to prevent mold growth during storage. Label all storage containers with the herb’s name and date.

Freezing Herbs
Quick-frozen herbs will keep up to one year in the freezer if well packaged. To tray freeze herbs, wash herbs, drain, and pat dry. Strip leaves off stems, spread leaves in a single layer on a cookie sheet and place in freezer for at least 30 minutes. Place frozen leaves in freezer bag. Label with herb’s name, date, and return to freezer for use as needed. Cut herb leaves can also be frozen in ice cubes, see directions under basil in Herb Characteristics and Preservation Information Table. Frozen herbs are best used in cooked dishes as they will become limp when thawed.

This table summarizes the flavor profile, harvesting, preservation methods, and culinary uses for several herbs that can be grown or purchased fresh in Colorado. Many popular herbs are members of the mint (Lamiaceae) and carrot (Apiaceae) families. For more information about growing herbs in Colorado, please see Herb Gardening, CMG GardenNotes #731.

Herb Characteristics and Preservation Information

Characteristics/Culinary Uses Preserving
Anise (seeds), Pimpinella anisum; Carrot Family
Used to flavor cookies, candies, pickles, beverages, breads, and fig dishes. Cut stems of seed heads after seeds have developed but while they are still green. Tie the stalks in small bunches and suspend inside a paper bag with holes punched in the sides. Suspend the bag in a dark area with good air circulation. When dry, shake the bag well and collect the seeds; store in light-proof airtight containers.
Basil, sweet (leaves), Ocimum species; Mint Family
Tender green leaves have sweet flavor with wild pungency. Used in Italian and Thai dishes as well as pesto.  Excellent with tomatoes, cheese, green salads, eggs, yogurt, soups, stews, lamb, and fish. When the plant starts to flower, cut stems 6 to 8 inches above ground, about 1/4 inch above a stem node. Wash leaves well before drying or freezing. Basil dries well in microwave oven at a low setting. When dry, leaves will crumble easily. Store whole or crushed in airtight containers. To freeze, pack washed leaves in ice cube trays half-filled water, pressing leaves under water as much as possible. Freeze overnight. Top off the trays so the leaves are completely submerged in water and re-freeze. When frozen, remove cubes and store in label and dated plastic bags. Defrost in a strainer and use as fresh.
Bay (leaves), Laurus nobilis; Laurel Family
Leaves are aromatic with a sweetish odor and pungent flavor. A classic ingredient in French bouquet. Used in sauces, pickling, stews, and with meats and potatoes. Bay leaves are tough and should be removed before serving. Complements tomatoes, beans, potatoes, and beef. Pick individual leaves to use fresh or preserve. When dry, pack in airtight containers. To freeze, see basil.
Burnet,  Sanguisorba minor; Rose Family
Perennial herb with a light cucumber flavor, used in flavoring butter, cottage cheese, cream cheese, potato salads, and salad dressings. Select young leaves as older leaves may be bitter. May be used in place of mint leaves but does not keep flavor well when dried or frozen.
Caraway (seeds), Carum carvi; Carrot Family
Mostly used whole in rye breads, sauerkraut, cheeses, potato salads, meats, and stews. Cut plants to ground level when flowers and stalks turn grayish-brown, about a month after flowering. For air drying, see anise; seeds shake out easily when fully ripe. Store in airtight containers.
Chervil (leaves), Anthriscus cerefolium; Carrot Family
Has a light, licorice flavor with a wild taste of pepper. Gives pleasant flavor to salads and salad dressings, meats, fish, soups, omelets, and stews. Pick only young, tender leaves just before the buds break, fresh chervil has a short storage life. To dry or freeze, see basil.
Chives (leaves), Allium schoenoprasum; Onion Family
Flavor is similar to green onion, but milder and finer leaves. Used for light, oniony flavor in salads, dips, sauces, vegetables, soups, fish, etc. Use leaves fresh by snipping off the tops with scissors. Chives lose their color and flavor when dried. To freeze, wash and chop finely, then continue as for basil.
Cilantro, Coriandrum sativum; Carrot Family
Used in Asian and Latin American dishes. Goes well with corn, cucumbers, avocado, rice, fish, and chili peppers. High heat reduces flavor. Freezes well in ice cube trays, see basil. Note: Cilantro leaves contain chemicals called aldehydes which impart a flavor characteristic which is disagreeable to some people
Coriander (seeds), Coriandrum sativum; Carrot Family
Small, orange-flavored seeds used in cold cuts, curry powder, cakes, cookies, poultry dressings, French dressing, and Scandinavian cooking. Same plant is source of cilantro. For air drying, see anise. When seeds are dry, shake out of heads and store in airtight containers. Flavor improves if stored a month before using.
Dill (seeds, leaves), Anethum graveolens, Carrot Family
Seeds have slightly bitter taste. Used in soups, pickles, cheese dishes, breads, sauces, meats and fish. Dill weed has delicate bouquet. Used to flavor fish sauces, salads, dips, potatoes, and meats. Pick young leaves just as flowers open. Cut leaves and spread in a thin layer to dry until brittle. Crumble leaves and store in an airtight container. To collect seeds, cut flower umbel stalks or pull entire plant from ground. See instructions for anise seeds, store in airtight containers.
Fennel (stems, leaves, seeds), Foeniculum vulgare; Carrot Family
Yellowish-brown seeds with sharp, sweet, licorice-like flavor; used to flavor sausages, breads, salads, salad dressings, pickles, cheese spreads, soups, and sauces. Leaves garnish or flavor sauces and salads. Young stems can be used like celery. Pick young leaves to dry, as for basil. Cut off flower stems before seeds fall. Store in airtight containers.
Horseradish (root, leaves) Armoracia rusticana; Mustard Family
Home prepared horseradish is about twice as strong as store-bought and lasts 3 to 4 weeks in the refrigerator. Excellent with roasted and smoked meats. Young leaves may be added to salads. Rinse the horseradish roots well. Horseradish has potent volatile compounds so work in a well-ventilated room, or outdoors, and protect your eyes. Peeling under water will help contain the volatile oils. Chop in a food processor with a small amount of water. A basic horseradish recipe is: 1 root + 4 Tbsp water, add 2 Tbsp vinegar, ½ tsp salt. Transfer to a jar and refrigerate. Excess shredded root may be sealed in freezer bags and frozen up to 6 months.
Marjoram, sweet (leaves), Origanum majorana; Mint Family
Gray-green leaves with slightly bitter undertone. May be used fresh or dried to season vegetables, lamb, sausage, eggs, poultry, cheese dishes, potato salad, stuffings, and soups. Cut stems just before buds begin to flower, leaving a few leaves to send up another crop. Dry as for basil.  When dry, crumble and store in airtight containers. To freeze, follow tray freezing directions above or pack small bunches in plastic bags and place in freezer. Blanch before freezing if storing more than 2-3 months.
Mint, spearmint, peppermint, apple mint, orange mint (leaves); Mint Family
Refreshing odor and flavor. Often used as garnish. Flavor combines well with lamb, peas, fish sauces, yogurt, candies, chocolate, and vegetables. Crush leaves just before adding to a dish. Pick young, fresh leaves to dry. Dry or freeze as for basil.
Oregano (leaves), Origanum species; Mint Family
Flavor similar to sweet marjoram, but stronger and more sage-like. Liberally used in Spanish and Italian dishes, pizza; component of chili powder. See sweet marjoram for preserving instructions.
Parsley (leaves), Petroselinum crispum; Carrot Family
Finely curled, aromatic leaves are rich in vitamins A and C. Used as flavoring or garnish for soups, salads, eggs, meat and poultry dishes, creamed vegetables, and hot breads. Parsley can be dried or frozen as for basil, but the flavor is better if frozen.
Rosemary (leaves), Rosmarinus officinalis; Mint Family
Leaves have a spicy odor and warm, piney taste. Used as a garnish and to flavor vegetable and meat dishes, cream soups, sauces, and jellies. Makes a good tea. Air or microwave drying works well for rosemary and other sturdy herbs; when dry, rub leaves from stem and store in airtight containers.
Saffron, Crocus sativus; Iris Family
Yellow stigmas are pleasantly bitter, give a yellow hue to foods. Used sparingly in sauces, cookies, cakes, chicken, gravies, and Spanish rice. Remove stigma in late fall and dry on a cloth in a warm room. Store stigma in airtight containers.
Sage (leaves), Salvia officinalis; Mint Family
Strong bitter flavor. Used sparingly in stuffings, soups, stews, sausage and herb breads. Pick leaves in spring before flower buds form, or flavor becomes musty. Dry or freeze as for basil. To store more than three months, blanch before freezing.
Summer savory (leaves), Satureja hortensis; Mint Family
Used in poultry, soups, gravies, stuffings, salads, bean dishes, sauces for fish or veal. Cut leafy tops and use only young, tender leaves. Remove woody stems. To dry, see basil.
Tarragon (leaves), Artemisia dracunculus; Sunflower Family
Considered essential in many French dishes, goes well with eggs, poultry, fish, shellfish, and many vegetables. Used as flavoring in pickles and vinegar. Use fresh young leaves and stem tips. To dry or freeze, see basil.
Thyme (leaves), Thymus vulgaris; Mint Family
The leaves have unique aroma and flavor. Good with roast meats, fish chowders, sauces, soups, gumbos, stews, stuffings, and salads. Makes a flavorful tea. Cut sprigs before the plant flowers. After drying, rub leaves from stems and store in airtight containers. To freeze, see sage.

References

Kendall, P. and J. Rausch. 2012. Making Flavored Vinegars. Oils. CSU Extension Fact Sheet no. 9.304. Available at: >http://extension.colostate.edu/topic-areas/nutrition-food-safety-health/flavored-vinegars-and-oils-9-340/.

Kendall, P., P. DiPersio and J. Sofos. 2012. Drying Vegetables. CSU Extension Fact Sheet no. 9.308. Available at: http://extension.colostate.edu/topic-areas/nutrition-food-safety-health/drying-vegetables-9-308/

National Center for Home Food Preservation. Drying Herbs. Available at: http://www.uga.edu/nchfp/how/dry/herbs.html.

Nummer, B.A., D. Schaffner, A. Frazer and E.L. Andress. 2011. Current Food Safety Issues of Home-prepared Vegetables and Herbs Stored in Oil. Food Protection Trends, 31 (6): 336-342.

O’Meara, C., A. O’Conner, and C. Bragg. 2013. Herb Gardening. CSU Extension CMG GardenNotes #731. Available from: http://www.ext.colostate.edu/mg/Gardennotes/731.html

University of Delaware Cooperative Extension. 2012. Using Herbs and Spices. Available at: https://www.udel.edu/academics/colleges/canr/cooperative-extension/fact-sheets/using-herbs-and-spices/

Woo, D. 2010. Microbial Quality of Mixed Salad Greens and Selected Fresh and Dried Herbs. M.S. Thesis. Dept. of Food Science & Human Nutrition, Colorado State University.

Youger-Comaty, J. 2010. Growing, Selecting and Using Basil, Ohio State University Extension Fact Sheet. Available at: http://ohioline.osu.edu/hyg-fact/1000/1644.html

Photo Acknowledgements: Gardens on Spring Creek, Fort Collins, CO

Authors: Marisa Bunning (CSU Extension, Associate Professor Department of Food Science and Human Nutrition), Daniel Woo (former graduate student, Department of Food Science and Human Nutrition), and Pat Kendall (Professor emeritus, Department of Food Science and Human Nutrition)