Back in the spring, I posted a few pics to the social medias about how I was making infused oils (dandelion and shepherd’s purse, at the time) and got a lot of questions about my method because of issues with mould.
That is a real thing.
I remember being gifted with a gorgeously prepared bottle of rosemary infused olive oil that looked so pretty, but began to develop mould just a couple of days after receiving it.
It’s super-annoying to have stuff go mouldy when ingredients, like dandelion and shepherd’s purse, are only accessible once a year and in a very brief window. As such, this method may seem a bit pedantic, but I assure you that I have not once had an oil go mouldy or turn prematurely rancid since sussing it out and employing it.
See the shepherd’s purse oil at the forefront in the featured pic? I put that up in May and have neglected it ever since. No mould. Not rancid. I really should strain it off and do something with it soon, though, as I’ve a balm for kitchen workers in mind and a few kitchen workers in my life who could use it.
What you need:
- White vinegar
- Cold water
- A clean space large (and traffic-free) enough to accommodate drying your herbs for 24 hours – I like to use the top of my portable dishwasher for this, but any surface you won’t need for that period of time will do
- Enough kitchen towels to cover said space
- A sterilized jar or jars with tightly-fitting lids enough for the amount of oil you would like to make – I like to use 500ml jars (basically a pint) because anything smaller seems like a waste of time and anything larger gets me worried about ruining a whole batch of good ingredients even though I’ve done this a million times before
- A good quality carrier oil – grapeseed and olive oils are my go-tos, but you’ll want to take into consideration the finished infused oil’s application and your personal preferences when deciding. For example, should you like to make a chili/garlic oil for stir frying at high temperatures, you’ll want to use a carrier with a high smoke point, like peanut or sunflower oil, but if you’re making an oil that you’ll later use to make hand cream, the viscosity and neutrality of grapeseed is your friend.
- Enough herbs to fill your jar 1/2 to 2/3 of the way full – assuming you’re working with 500ml/pint jars, you’ll need 1 cup of packed herbs per jar
- A chopstick or butter knife
- A pot or two large enough to fit the jar(s) of oil into
- A candy or meat thermometer
- A stovetop burner that can be used for a few hours
- A fine sieve
- Bottles for storage
What you do:
- Pick your herbs and give them a bath in lots of cold water and 1/4 cup of white vinegar for 15 minutes.
- Rinse your herbs in cold water and gently dry them with kitchen towels, then spread them out in a single layer on the clean, traffic-free space covered with kitchen towels you’ve prepared. Let them sit for 24 hours. This pre-shrinking step is important as it helps get rid of excess mould-inducing moisture and gives a chance for any remaining bébites that may still be calling your herbs “home” a chance to get away.
- After the pre-shrinking phase is over, fill your jar(s) 1/2 to 2/3 full with your herb(s) and then fill them up with your carrier oil. Use the chopstick or knife to stir/poke out any air bubbles.
- Put the jar(s) in your pot and fill the pot with water to about halfway, like so:
- Heat the pot over medium-low heat for about half an hour, using your thermometer to ensure the temperature of the oil does not go above 120 degrees, then turn it down to low. I use setting 4 on my burners, which go from 1 to 10, for the first half hour, then turn it down to between settings 2 and 3.
- Let the oil steep for 2 to 2.5 hours, checking the temperature with the thermometer periodically to ensure that is stays between that 100 and 120 degrees sweet spot.
- After the 2 to 2.5 hours have passed, the colour of your oil will have changed dramatically, taking on the colour of the herb(s) within and should smell quite pungently of the herb.
As you may have guessed, the jar on the left in the pic above is what the oil looked like before heat infusion and the jar on the right is the result of the heat infusion. Such DRAMA. If your oil is meant for consumption, don’t be afraid to taste test. If it isn’t quite where you want it to be, let it steep for another 15 minutes and check again.
- Once the heated part of the infusion is complete, remove your oil(s) from the pot(s) and let cool to room temperature, then lid them and place them in a sunny window for 2 weeks. Technically, you don’t need to do the two weeks in the sunshine thing, but I find I get a superior product when I do.
- Once the two weeks are up, strain your oil(s) through a fine sieve lined with cheesecloth to remove the solids. Toss those in your composter, then bottle your oil up in whatever vessel(s) you intend to store it for use/gifting.
Putting it into practice:
The test oil I set up yesterday just so I could take proper notes to ensure no steps were missing so I could bring this tutorial to you, my lovely readers, in a technically sound way was a basil/mint/chili/garlic oil. A combined oil that is a great starter because it’s something that has a lot of applications and is very gratifying in how quickly you can see and smell the infusion happening. It’s also a really good application for mint and basil flowers, which many folks seem to not know what to do with. I like to keep a bag in the freezer for collecting them through the growing season until I have enough for oil.
Think about giving it a whirl for your first go. It contains:
- 3/4 cup packed basil flowers, stems and leaves
- 1/4 cup packed mint flowers, stems and leaves
- 4 dried whole chilies, broken in half
- 4 cloves of garlic, smashed
Just follow the instructions above and soon you’ll have a lovely, flavourful oil for drizzling on salads, over pasta, or dipping bread in.