Making Herbal Heat-Infused Oils is not as tricky as you might think. Really, it's not. Herbal oils are not the same as essential oils. E.o.s are highly concentrated essences of the plant. Dried herbs contain essential oils, but many herbs have so much more to offer than just essential oils, and herbal-infused oils are used in many homemade herbal remedies. Salves, homemade lotions in the blender, whipped body butters, hair treatments, cleansing creams and oils. Even cooking. Rosemary garlic infused oil is lovely drizzled over chicken pasta.
I want to show you how to make a heat-infused oil. I have been waiting, impatiently, for the last three days while I finished photographing each step, so that I could not only post this tutorial for you but then finish writing several other recipes that require a herbal infused oil! I couldn't give you those recipes without this first! I will also show you at a later date how to make infused oils without the heat. Fresh rose petals infused into apricot kernel oil, the heatless way, is amazing... That post will come this summer once my roses bloom! For most herbs, though, this crock pot method is faster, and my go-to method for most herbal oils.
Today, I am making olive oil infused with calendula, and olive oil infused with jasmine green tea. Once the base oil is infused, stored correctly the herbal oil should last about three years. That's pretty cool.
- wide mouth glass canning jar, pint or cup, with lids
- base oil for infusing -- olive, coconut, apricot kernel, grapeseed, almond, jojoba, avocado...
- herbs for infusing into the oil -- 1 oz weight for a pint jar, 1/2 oz weight for a cup jar
- slow cooker / crock pot with "keep warm" setting
- thermometer if needed
- clean cloth for straining
- clean glass jar for straining
- masking tape and permanent marker for labeling
- optional Grapefruit Seed Extract (GSE) and vitamin E oil for preservatives
Begin by measuring out your herbs by weight. You will need 1 ounce of herbs for a pint jar, other size jars do the math accordingly. This basic rule of 1 oz per pint applies to infused oils, infused vinegars, alcoholic tinctures, glycerites and honeys.
Pop the herb of choice into the jar. Get a toddler to carefully help.
Fill up with base oil. Pictured is jasmine green tea with olive oil. Once the bubbles have finished rising and the herbs are soaked with oil, top up again, bringing the oil level to about 1/2 inch from the top of the jar, leaving the same approximate head space as for canning homemade jam. The oil will expand as it heats so it's a good idea to allow a little room to prevent bubbling over.
This is calendula. Do you see the difference in volume between the 1 oz green tea and this 1 oz calendula flowers? The green tea oil will amount to more, as there is more room in the jar for the olive oil, but you will gain more consistent results in quality if you measure by weight than by volume.
Both my calendula and green tea oils are ready for infusing. Measured, filled, lids and bands on, and then I like to stick a quick label with masking tape and permanent marker on the top of each jar, just in case I forget what is in each one. I don't like to waste energy so usually make more than one product at a time when I am using the crock pot. The marker and masking tape won't bleed when wet which makes them ideal for these sorts of labeling needs.
Place jars in the crock pot. Fill up with water up to the neck, where you see my thumb indicating. Keep the crock topped up with hot water as it evaporates.
Set the crock pot to "keep warm". Leave it for THREE DAYS to heat infuse the herbs into the oil.
Well, don't fully abandon it! If your crock pot tends to run hot, as mine does, it may get too warm for some herbs. You want to heat them consistently so they release all their goodness into the oil, but you don't want to actually fry them. Some herbs, such as arnica, do better on a low heat around 110-115 F, much like yogurt, and will lose a lot of goodness when overheated. Other herbs, like my jasmine green tea or echinacea purpurea root, can handle a bit more heat to bring out their goodness. Generally speaking, soft herbs require less heat and hard herbs require more -- just as in the difference between infusing (boiling water over the top and letting steep) soft herbs for tea and decocting (simmering 20 minutes) hard herbs for tea.
If your crock runs warm, place a rag on the bottom, underneath the jars, and stick a thermometer in as well. Keep an eye on the temperature. If you need, you can turn the "keep warm" setting on and off every hour throughout the day, turning the crock off at night, for the three days of heat infusing.
Once the time is up, pull the jars of oil and let them cool a bit. You will be using your hands, so while the oils should still be warm, don't try it when they are too hot.
Line a spotlessly clean and dry glass jug with your spotlessly clean and dry cloth. Do not allow any dampness to happen here! Oil and water don't mix, and if you get moisture into the oil, it will likely grow mold after only a few months, certainly not lasting years. If that happens, throw it out. All of it. Mold has already run the length of the entire product if you see a flower in one place, and you don't want that on your skin or in your body. This is not lacto-fermented cheese.
Dump the contents of your jar, oil and all the herbs, into the center of the cloth. Pull up the sides, let drain, and squeeze thoroughly to get all the goodness, all the oil and the healing properties, out of the herbs as much as possible.
My honey took this photo for me as my hands were, clearly, both tied up!
You may add one drop per ounce of infused oil of each of the GSE and vitamin E oil (not for cooking). They will help preserve your infused oil for longer at maximum potency. Store the oil in spotlessly clean and dry glass jars, with properly sealed lids, and label.
Labeling is important! Never rely on memory. Use the masking tape and permanent marker, again, since they peel off jars for easy cleaning later and won't bleed in case of spills, and note the full contents of the jar and the date.
Store your infused oils in the dark and cool. A cabinet is fine in most cases. Some like to store in the fridge. No higher than 75 F is a good idea, though. See the gorgeous colors in the finished herbal oils here? I don't keep them on the kitchen windowsill! I just wanted to show you the lovely buttery yellow that calendula lends, and the darker green that olive oil becomes with jasmine green tea. These will make beautiful, healing, skin nourishing beauty products, used just as they are or turned into lotions and potions!