It’s very simple to learn how to solar infuse herbs and the process is a great way to include herbal components into a wide range of salves, creams, and soaps.
Unlike modern extraction methods that often use harsh chemicals and solvents, solar infusion is the traditional way of extracting natural compounds from herbs and has been used for thousands of years.
The best part? You only need three inexpensive items — a Mason jar with lid, vegetable oil, and herbs — to start your own batch of solar infused herbs!
How to Solar Infuse Herbs
You can infuse both fresh and dried herbs and the basic process is the same.
The part of the herb that is harvested can also impact your final product, so keep in mind the difference between leaves, roots, and flower of whatever herb you’re interested in working with.
Working with fresh herbs is slightly more challenging, especially if they naturally have high water content and/or are very oily.
You’ll be using heat to draw out natural compounds present in the plant matter of your herbs, which your vegetable oil will absorb.
Those things — natural compounds and oil — are good and are what you’re aiming for. Water, however, is bad and can cause your oil to go rancid and develop mold.
The tendency of oil and water to separate is our friend here, so with a little care and patience we can naturally infuse our oil with herbs and end up with an infused oil with a shelf life of well over a year.
Infusing Herbs in Oil
We’ll start with working with fresh herbs, as dried herbs are a relative snap. Collect the herb you’d like to work with and give it a good washing in the sink and let it air dry.
Put your herb loosely into a Mason jar until it is about 2/3rds full. Just loosely fill the jar and don’t pack the plant material in.
The size and amount of herb and the size of the jar is up to you, although an eight ounce Mason jar is likely a good starting point as it will typically produce 3-4 ounces of infused oil.
Now you’ll pour your vegetable oil into the jar until it just covers the plant material.
The choice of vegetable oil is up to you and is often determined by the finished product that you’d like to add the infused oil to.
We often infuse herbs in castor oil for use in our soaps or in rice bran oil when it will be going into our Dandy, Quitch, and Stitch salves.
Olive oil is another popular choice as an oil to infuse herbs in. Any vegetable oil will work so it really depends on how you’d like to use the oil and what you have on hand.
After you’ve added your oil, screw the lid on and place the jar in spot that will get a lot of direct sunlight.
Let your herbs solar infuse for 2-3 days, then strain off the plant matter. We like to use a jelly strainer bag, but cheesecloth will also work well.
You’ll need to have a clean jar handy, as you’ll dump the content of your original jar into your jelly bag or cheesecloth and strain the oil off into the clean jar.
Squeeze the bag or cheesecloth firmly to get as much oil as possible out. Discard or compost the plant material.
When you’re done you’ll be left with just infused oil in the new jar. Let that sit for several days and watch for any separation of oil and water.
If you do have water form at the bottom of the jar, simply strain off the oil on top one final time, discarding the water and oil at the very bottom.
Working with dried herbs is somewhat simpler, as you don’t have to worry about water content. Fill your jar about 1/2 full with dried herbs and cover in oil.
You can let dried herbs infuse for much longer than 2-3 days as water and mold isn’t an issue. Strain off the dried herbs just as detailed above, with your infused oil now ready to use.
And that’s all there is to learning how to solar infuse herbs! If you’d like a more concentrated infused oil, simply repeat the above steps by adding herbs to a new jar and then covering with your infused oil, which will result in a double infusion.
We’ve focused on the herbalism side here but infused oils ca also be used in the kitchen, such as infusing olive oil with herbs like rosemary or thyme.