Understanding Herb Categories: Tender vs Hardy Varieties
There are two types of fresh culinary herbs found at farmers’ markets and in the produce aisle at the grocery store: tender herbs, also known as soft herbs, and hard herbs. Tender herbs have soft stems and soft leaves; they include cilantro, tarragon, parsley, dill, mint, and basil. Hard herbs have hard, woody stems and stiffer leaves. Popular hard herbs include rosemary, oregano, thyme, bay leaves, and sage. This distinction matters enormously when you’re choosing how to freeze them.
Think of tender herbs as the delicate flowers of the herb world – they need gentler handling and different freezing techniques than their woody counterparts. Many herbs can be simply frozen on the stem and stored in an airtight container. Left on the stem, hardier herbs like rosemary, dill, thyme, bay or sage can be spread in a single layer on a baking sheet or plate and placed in the freezer. Once frozen, transfer them into an airtight container for freezer storage without clumping. To use, simply remove herbs a sprig at a time.
Perfect Timing: When to Harvest for Optimal Freezing
Most herbs are best for drying just before the flowers first open. Flowering herbs tend to be somewhat bitter. New leaves at the tip of the plant will have the most concentrated flavor. Picture the herb’s lifecycle like a crescendo in music – right before it hits that peak flowering moment is when all the flavor compounds are most concentrated.
Select fresh herbs in mid-morning when dew is off the plants but before the sun has evaporated the oils that provide the flavor. Early morning harvesting isn’t just an old wives’ tale – it’s science. For best results harvest most herbs just before they flower when their oils are most concentrated. Early Morning Harvest: Pick herbs in the morning, after the dew has dried but before the day’s heat. The essential oils that give herbs their punch are at their peak concentration during this golden window of time.
Essential Preparation Steps Before Freezing
Pick herbs in the morning, just after the dew evaporates and before the sun is hot. Discard bruised, soiled or imperfect leaves and stems. With the leaves on the stems, lightly wash in cool running water. Gently shake to remove excess water. Drain on paper towels. This isn’t just about cleanliness – damaged leaves can affect the quality of your entire batch.
Proper washing is crucial but delicate work. Before freezing, soak the herbs in a large bowl of cold water. Swish them around to dislodge dirt, debris, or insects, especially if you’re harvesting them from your own herb garden. You can do this with or without stems attached. Remember, you’re handling these herbs like precious gems – they’re fragile and deserve gentle treatment to preserve their cellular structure as much as possible before the freezing process breaks down those cell walls.
The Science Behind Cell Wall Expansion During Freezing
Keep in mind that freezing will cause the water in the cell walls to expand, and the herbs will be limp when thawed. As a result, you may prefer to use frozen herbs in cooked dishes. This is the reality check every herb-freezer needs to understand. When water freezes, it expands by approximately nine percent, and that expansion bursts the delicate cell walls that give fresh herbs their crisp texture.
Freezing bursts the cell wall structure which causes them to lose their turgor and go limp, so I use frozen herbs like Basil, Cilantro, Parsley, Rosemary, and Dill to offer garden fresh flavour in cooked items like sauces, soups, and foods that are baked like pizza toppings. Think of it like this: fresh herbs are like crisp lettuce leaves, but frozen herbs become more like cooked spinach – all the flavor is still there, but the texture has completely changed. They will generally not be attractive as garnishes.
Ice Cube Tray Method: The Most Popular Technique
Fill an ice cube tray half full of water. Place herbs in each section of the tray – about 1 tablespoon in each. Push herbs under the water as much as possible. Place in the freezer. The next day when herb cubes are frozen solid, add additional water to top off the cube. Return to the freezer and freeze solid. This method is like creating little herb time capsules.
Next, place the chopped herbs in an ice cube tray; from my experience, silicone trays work best. Fill each well with water, just enough to completely cover the herb mixture. Press the herbs into the water so they are fully submerged. Place the ice cube tray in the freezer and freeze for 3-4 hours. Once frozen, transfer the herbs into an airtight container or freezer-safe zip top bag labeled with each type of herb, and store in your freezer for up to 6 months.
Oil-Based Freezing: Preserving Color and Flavor
Mix ⅓ to ½ cup of oil with 2 cups of chopped herbs. (The oil allows the mixture to be scraped from the jar more easily because it doesn’t freeze as hard.) This can be frozen in ice cube trays and used as above, or it can be frozen in small jelly jars. The oil will not freeze solid like ice, and you can scrape out the amount you want to use. A neutral flavored vegetable oil such as canola oil allows the flavor of the herb to dominate. Olive oil is suitable if it complements the flavor of the herb. Herbs frozen in oil maintain their color better than those frozen individually. This method works well with basil.
Olive oil or butter helps to retain the potency of fresh herbs in the freezer. The oil acts like a protective barrier, almost like a natural preservative that shields the herbs from the harsh effects of freezing temperatures. Coating the herbs in oil adds an additional level of protection, especially against freezer burn. The oil will also contribute to the dish the herbs will be added to. Adding olive oil to your ice cube herbs, for example, is optimal for sautéeing or adding to a soup.
The Blanching Debate: To Blanch or Not to Blanch
There’s no need to blanch herbs for freezing. Just wash all herbs in cool, running water and pat dry before freezing. This is where herb experts sometimes disagree. Freezing herbs is easy. There’s no need to blanch them; just rinse, remove the leaves from stems if desired, and freeze.
However, some experts advocate for selective blanching. Another option is to blanch leaves of larger herbs such as basil for 15 seconds to stop enzyme reactions. Immediately plunge in ice water to stop the cooking. Drain, pat dry and freeze on a tray before packaging. Blanching remains an ideal step to take before freezing herbs. If your herb garden is overflowing (what a wonderful problem to have) be sure to blanch and freeze your herbs (in a plastic bag) so you’ll have lovely, vibrant herbs all year long. The choice often depends on whether you prioritize color retention or convenience.
Proper Container Selection and Odor Prevention
Strong smelling herbs should be double wrapped in foil or placed in freezer jars to avoid the transfer of odors. This isn’t just about being neat – some herbs like mint or rosemary can perfume your entire freezer if not properly contained. Herbs give off odors that can be absorbed by other foods in the freezer. Avoid the transfer of odors by wrapping herbs in foil or placing in glass jars with an airtight lid. Plastic freezer bags and boxes suitable for freezing vegetables and fruits allow for the transfer of odors.
To prevent odor transfer in the freezer, store them in freezer bags or airtight containers. Your ice cream doesn’t need to taste like oregano, and your frozen vegetables shouldn’t smell like basil. Think of proper containment as being a good neighbor to your other frozen foods.
Smart Portioning Strategies for Convenient Use
Consider how you will use the herbs. You will want to use a measuring cup to fill the yogurt container with an appropriate amount of the herb. For soups, between 1/4 and 1/3 a cup is perfect, depending on the size of the recipe. Since I cook soup in 10-12 serving batches, I generally freeze herbs in 1/3 cup increments. This forward-thinking approach saves you from having to chisel apart frozen herb blocks later.
Be careful with quantities when sealing herbs. A savvy cook will only seal portioned sizes that are large enough for particular dishes. Any more will cause you to waste ingredients resealing the leftovers or waste vacuum sealer bags by storing them again. Moreover, you won’t need to measure the amount to use after pulling the herbs from the freezer. Vacuum sealing the correct portion size will streamline cooking into a simple process.
Usage Guidelines: From Freezer to Kitchen
The best part about learning how to freeze fresh herbs is that there’s no thawing step. Letting the herbs thaw will either result in limp and soggy herbs (if you froze them still on their stem) or watered-down herbs (if you froze them in water or with oil). Instead, add the frozen herbs directly to your dish for the best results. This is the golden rule that many home cooks get wrong.
To use, add a frozen cube in soups, sauces, stews or other combination cooked dishes. Frozen herbs are great to have in your kitchen at all times, and you can use them to substitute fresh herbs in most recipes. When making hot foods, such as soups, stews, and sauces, you can add frozen herbs to the recipe without thawing. The heat from cooking will gently thaw and distribute the herbs throughout your dish, giving you that fresh herb flavor without any textural issues.
