Herbal Oils 101
Salves and herbal oils are delightful balms for soothing skin irritation, dryness, and inflammation. Botanical-infused oils act to extract and preserve the medicinal qualities of herbs, providing a convenient and pleasureable form of a topical application. Certain constituents in healing herbs are readily extracted in oils, including volatile or essential oils, lipids and resins. Preparing herbal oils is quite easy, especially if you follow a few basic guidelines. Remeber that oil can ferment or mold when water is added and can ruin your oil. For that reason, we like to work with dried herbs, with a few exceptions.
You can use any oil but some of the most popular ones are olive oil, coconut, jojoba, or sweet almond oil. Look for oils that are unrefined and cold-pressed or expeller-pressed. After preparing your herbal-infused oil, you may then tranform it into an herbal salve, body butter, or cream.
Preparing an Herbal-Infused Oil
Here are my two preferred ways of infusing herbs in oil: the maceration method and the heat method. You can use either of the following methods alone, or you may choose to employ the maceration method followed by the heat method. For resinous herbs, I highly recommend using heat to gently melt and extract the resin. You will end up with considerably stronger oil this way! Additionally, the heat method is convenient if you need a medicinal oil right away, as it only takes one day to complete the process.
Proportions for either method: Use equal parts, by volume, of dried herbs to oil. For example, if you measure out 1 cup of herb, or herbal blend, you will use 1 cup of your oil of choice. There is no exact weight-to-volume measurement. It is fine to combine multiple herbs in a single jar or pot for a specific formula.
Maceration Method
Gather your herb(s) and dry thoroughly; if purchasing dried herbs, make sure they are fresh and high quality. If you’re using home-dried herbs, combine the dried herb with extra-virgin olive oil in a blender, food processor, or Vitamix so the herb is completely covered with oil and blended to a coarse texture. Aim for a coarse, pesto-like consistency. Blending your herb to a fine texture will create a more concentrated oil by increasing the surface area of herb exposed to the oil.
Place the herb/oil slurry in a clean, dry, glass jar, taking care that the herb is completely submerged in the oil by 1 to 2 inches. You may need to top off the herbal slurry with additional oil. Label and place the jar in a dark cabinet for four weeks.
Exception: If you are making Saint John’s wort (Hypericum perforatum) oil, use freshly wilted flowers do not blend, and place in a sunny window for four weeks.
After the infusion is complete, strain your slurry, or finish your oil off with the heat method (especially with resinous herbs).
Heat Method
We have found that adding a little but of heat really helps the oil extract the medicine from the herbs. Blend your dried herbs as outlined above if you are using homegrown herbs. Follow the same proportions: 1 part herb by volume to 1 part oil by volume.
Stovetop Method: Place the herb/oil mixture in a double boiler. You can improvise a double boiler by nesting two pots together or placing mason jar bands upside down in a saucepan filled with water. The trick is to nest one pan so that it is raised off the bottom pan, which is filled with water. Heat slowly and keep on low heat for four to eight hours. Do not let the oil get hotter than 110 degrees F. Watch closely to make sure the water does not completely evaporate and the oil does not get too hot.
Straining Your Oils: After you have prepared your oil, the next step is to strain it into a glass jar or measuring cup. You can use a number of different cloths to strain your oil: muslin cloth, tighter -weave cheesecloth, cotton gauze fabric, or a clean, old t-shirt. If the oil is slightly warm, it will be easier to strain. Place the cloth in a stainless steel or ceramic coffee strainer and pour in the oil/herb slurry. After the oil ceases to run through the cloth, wring out the herbal material with clean, dry hands or press with a potato ricer. Label your oil and add the lid when the oil cools to room temperature (this prevents condensation from developing inside the jar). You are now ready to make a salve. Store any unused oil in the refrigerator to prolong its shelf life. Herbal-infused oils will typically last two to three years when refrigerated and one year unrefrigerated, depending on the stability of the oil used.
Transforming Your Infused Oil Into Salve
Now that you have a lovely herbal-infused oil, it’s time to add the ingredients to transform it into a salve. Beeswax is the most common addition for hardening the oil, but you might also opt for adding solid plant butters, such as shea butter or cocoa butter. If you’re using solid oils or butters, decrease the amount of beeswax in your recipe. Start with a small amount of beeswax, and gradually add more as needed by testing out the salve with the spoon method outlined below. Additionally, this is the time for adding concentrated and precious oils, such as rosehip, jojoba, and argan oil.
Measure your oil, and then bring it slowly up to 110 degrees F in a double boiler. For every 4 fluid ounces of oil, add 1 ounce grated or beaded beeswax by volume.
Completely dissolve the beeswax into the oil. To test the consistency of your salve, place a spoonful of the mixture into the freezer for two minutes, pull it out, and test its hardiness. If it’s too soft, add more beeswax. If it’s too hard, add a little more of the infused oil.
Adding Essential Oils: While your salve is still warm, and right before you pour it into jars, you can add any desired essential oils. Alternatively, you can create different batches by adding the essential oil directly into the salve jar after its poured. As a general guideline, use approximately 1-2 drops of essential oil per 1 ounce of salve.
Shelf-Life: Salves will typically last one to three years unrefrigerated. Refrigeration is not necessary but will prolong shelf life. Vitamine E is often added to salve as an antioxidant to prevent rancidity. For every 10 ounces of oil, add 2 capsules of vitamin E oil, or 1/2 and teaspoon of liquid vitamin E oil.
Appropriate Use of Oils and Salves
When to use an infused oil or salve: Covering a large swath of the body in salve is often not desirable. Herbs used for widespread joint inflammation or injury are typically applied as an herbal-infused oil via massage rather than a salve. St. John’s Wort, arnica, and poplar buds are examples of herbal oils that are often massaged into the skin. Essential oils can be diluted directly into these medicinal oils as needed.
The beeswax in salve helps prolong its application on the skin, in addition to holding in moisture. When tissues are very dry or irritated, this quality is especially helpful. Oils tend to rub off quicker than salve, and thus require more frequent application. Salves are also solid, and thus more convenient to transport than oil.
Infused Oil Recipe
This is a wonderful all-purpose herbal oil. It can be used as a base for a salve or prepared into a cream or lotion. These traditional skin-healing herbs lend their soothing, anti-inflammatory, and wound-healing properties to the oil. It can be used on rashes, chafed skin, dry eczema, bug bites, scrapes, and bruises.
1/2 cup rose petals or buds
1/2 cup violet lead
1/2 cup comfrey root
1/2 cup calendula flowers
Yields 1 and 3/4 cups
Follow the steps outlined above for a macerated herbal oil. Once you are ready to strain, strain into dropper bottles with the help of a funnel. Have fun!