Herb infused oils are awesome for lots of reasons, but my favourite reasons are 1) you get the benefit of the herb without having funny chunky bits hanging out in your lotions and balms and 2) they just get better as they age, like whiskey, but cheaper (and you can still drive after partaking).
There are two ways to make herb infused oils, so I thought I’d run through both of them, and why I like each method.
For each method you’ll need the same things: a 500mL mason jar, a relatively large amount of a fairly inexpensive, shelf-stable liquid oil (olive, grapeseed, and safflower are all great choices), and the herb in question, dried (about 1/3–½ cup). You want to be sure to use the dried version so you don’t introduce any water into the oil, which will shorten the shelf life of the oil dramatically.
Method #1 is wonderfully easy: Put the herbs in the jar. Top off with oil & seal. Leave on a sunny windowsill for three weeks or so (shaking on occasion) before moving to a dark, cool cupboard. The initial dose of warmth and sunshine will speed the infusion, but after that you’ll want to move it so you don’t speed rancidity. You can use the oil after the first three weeks.
Method #2 is a bit more involved. Start with the first two steps of #1, but instead of sealing the jar, empty the contents into a small saucepan. Heat on very low heat, stirring, for half and hour. Let cool and then pour into the jar. Seal and store in a cool, dry cupboard. You can use the oil immediately. If your stove tends to run hot or you are absent-minded, it’s a good idea to do this in a double boiler as you don’t want to accidentally fry all your dried herbs.
The benefits of each method are pretty apparent: #1 is nice and passive, so you don’t really have to do much of anything. Great if you won’t need the oil for a few weeks. #2 is fast, just in case you don’t have the extra time to leave it for three weeks.
Usage for both types of oils is the same; simply spoon out the amount you need and run it through a sieve to remove any bits of herb, and then proceed with the recipe.
I’ve used both methods and I like them both. I always keep infused oils of calendula, comfrey, and plantain on hand for use in balms, salves, and body butters, and I’m sure that collection will continue to grow!