herbal oils, or herbal oil infusions, are used for culinary, cosmetic, and medicinal purposes. i make herbal oils for use in salves, balms, and lotions. herbs are soaked in a carrier oil for a specified amount of time, pressed and decanted before being put to use. during the soaking (or digestion) process, the oil soaks up the medicinal (soothing, pain-relieving, cooling) and desirable (aroma, color) characteristics of the herb. it sounds simple, but i find making oils to be messy and time consuming, but so worth it! this is a post about how i make my herbal oils
before we begin, i would like to offer that this is not a how-to post. there are plenty of resources in the world for how to make herbal infusions of all manner. i follow the ‘digestion method’ laid out in the herbal medicine maker’s handbook by james green. i highly recommend this text for anyone interested in making their own herbal preparations. i’m confident you could find it in your local library system or used from the internet.
although i follow the methodology laid out in the handbook, i add many extra-steps to ensure my oils do not contaminate. since i make products to sell online, as well as to give to loved ones, it’s super important to me to follow good manufacturing processes and to be somewhat scientific about extracting the desirable compounds from the herbs. it helps that i’ve been homebrewing from years – brewing beer requires absolute sanitation of all equipment, tools, work surfaces, and bottles. i love germs in everyday life (yes, i eat food off the floor), but when it comes to making self-care products i feel good about offering, i like to keep it as clean and precise as possible.
i still prepare all my products with love and intention, and these oils are no different! so let’s get to it.
first, i decide what type of herbal oil i want to make and at what volume and concentration. oils are made at a dried weight of herb to fluid ounce of oil ratio or your choosing – it varies by herb, intention, type of oil, etc. i measure out my dried herb using a kitchen scale and a cleaned and sanitized bowl. i use star-san as a sanitizing agent because it’s what we use for homebrewing and it’s readily available at your local homebrew store. when working with dried herbs, it’s important to make sure everything is totally dry or the herbs will wick up the moisture and this can lead to rancidity. i like to set my over to a low temp (200F) and stick clean and sanitary items in there to make sure they dry completely.
once the herb has been measured out, it should be powdered. this makes your oil look kinda ugly when it’s infusing because there are no pretty flowers floating around to look at … but simple science tells us that the more surface area creates a stronger and more even extraction. i powder my herbs using a spice grinder with a removable bowl, which makes for easy cleaning. before i grind the herbs, i garble it (pick through the herb to discard any stems, visible dirt, woody material) to make sure what’s going into the infusion is the highest quality herb.
at this point, the powdered herb is simply added to a container, and the proper amount of oil is poured over the top. i like to use mason jars because they are easy to sterilize and seal. the oil has to be shaken many times a day, so it’s important whatever the herb is stored in is airtight. anything that is holding the infusion for long periods of time (i.e. jars) are sterilized instead of sanitized. here’s the difference. to make sure the jars are sterile, i boil the jars, lids, and lid rings for 10 minutes, just like i would if i were canning jam.
after adding the oil and letting the infusion sit for a few hours, sometimes the herb absorbs all the oil and in this case i add more. i like to have a small rim of oil on the top of the soaking herb.
i ‘digest’ (the process of soaking the herb in oil) my oils for 10 days at 100F. you certainly can make an infused oil in just a few hours by digesting at a much higher temperature, but i prefer the slower approach. it feels right to me and i’m satisfied with the results. the extraction takes places steadily and evenly.
i accomplish holding the oils at this specific temperature using a homemade temperature controller, a clean and sanitized camping cooler, a heat mat used for starting seeds, and a tupperware of water that holds the temperature probe and tells the heat mat when to turn off and on. i’ve already read you can do this in a water bath or a yogurt maker, but that seems difficult to me to operate for 10 days? with the temp controller my process is pretty hands off.
while the oils are digesting, it is important to shake them throughout the day. this agitates the herb inside to force extraction to continue happening.
after 10 days, the oils are ready to be strained and pressed!
everything up to this point has been fairly straightforward. now things get messy – an apron is a must!
now that the oil has been infusing with plant matter for 10 days, i think it’s very important to make sure whatever is touching the oil during the straining process is properly sterilized. i strain using a sieve, muslin cloth, and a spatula, and i boil all of this for 10 minutes along with my jars, lids, and lid rings.
i also use sanitizer in a spray bottle to sanitize all my work surfaces, and only use washed and clean towels. i dry everything in the over at 200F like i mentioned above.
the messy part! the oil and herb is strained through muslin in small batches, wringing out the herb then sending it to the compost. one day i might get a fancy press, but for now i wring everything out by hand.
that’s it! between each type of infusion all the equipment gets cleaned and sterilized again. the strained oil sits for a couple days to allow any sediment to fall to the bottom, then is decanted and ready for use in homemade salves, balms, lotions, and other recipes!