Making an Herb Infused Oil – Part 2

In part 1 I talked about making an herb infused oil.  I know the herb I want to use and decided on a combination of 2 oils (sunflower and jojoba) that have some similar/some complementary properties.

Using Heat

When working with dried herbs (which when I am making an herb infused oil is 90% of the time) I like to use heat to do it.  I could place the herb material in a jar, cover it with oil and let the whole thing macerate over time – much like a tincture.  If I use heat though I can get the whole infusion finished in one day.  I am lucky that I have a crockpot with a warm function.  Many crockpots will be too hot to make an herb infused oil so check yours.  You don’t want to scorch the oil.  Keep your oils from heating to above 100 degrees Fahrenheit.  I checked my crockpot by filling it, leaving it on (lid off) and used a candy thermometer to check the temperature.

Keeping the Heat Down

If your crockpot is too hot there a few things you can try.  You will have to pay attention.

Leave the lid off.

Pulse the crockpot – turn it on for half an hour/turn it off for half an hour.

Put the lid on but prop it open with a spoon.

You can use a double boiler to heat your oil.  This technique means vigilance.  To ensure that the water does not boil dry and make sure the oil does not get too hot.  I am someone who has put soup on the stove, gone downstairs and 2 hours later said – crap the soup!  A technique that requires constant vigilance is not suited to my temperament.

Oil to Herb Measurements

I want to replicate my oils so when I make them again, they will be the same.  If you ever went free form and made a mouth-watering spaghetti sauce it can be frustrating to try and remember what you did that made it so delicious.

For making an herb infused oil I measure the herb by weight and the oil by ml.  Over time I have found that the ratio I want is

40 grams of herb material

300 ml of oil

 

 

 

 

 

 

I need 250 ml of oil for the face cream recipe.  After I infuse the oil and strain the herb material, I will have 250 to 300 ml of oil.

Before You Start.

It is critical to your success that everything you use is clean and dry.  Attention to detail is crucial.  You do not want the oil to go rancid.  Nor do you want mold to grow in your product.  Botulism is a concern, although more likely with fresh plant material.  Botulism toxin grows in an anaerobic environment and that is what an oil is.  While it is more of a concern for culinary oils that are to be ingested – the toxins can be absorbed topically.  After making the oil I add rosemary extract as a preservative – natural products are susceptible to going off.

Wash and dry all your equipment before you start.  Clean and sanitize the workspace and assemble all tools before you begin.

Using Fresh Herbs.

In making an herb infused oil some herbs should be used fresh.  The herb I immediately think of is St. John’s Wort.  The gorgeous ruby red colour – the hallmark of a quality St. John’s Wort oil – cannot be achieved with dry plant material.

When you use fresh herbs reduce the water content by wilting them.  I lay the herbs on a screen.  They dry for 24-48 hours before I place them in the oil. Reduce the weight of your herbs by half when you are wilting fresh herbs.   If for example I begin with 100 grams of fresh violet leaves, I weigh them and when they weigh 50 grams – I make the oil.

For oil infusions with fresh herbs I do not use heat but let them macerate for 4-6 weeks.  I know many herbalists who cover the jar with cheesecloth, I prefer to use an unbleached coffee filter that I can hold in place with the screw band.  This helps any moisture that might be in the jar to evaporate.  After a week I place a regular cover on the jar.

Folk Method.

If you are making an herb infused oil for yourself to use, you can use the folk method.  This is fancy way of saying – eyeball it.  Fill your jar with 1/2 to 2/3rds full of herb material and add oil to cover.  Don’t pack the herb too tightly – you want the oil to seep into all the spaces in the jar.  Be sure to submerge the herb underneath in the oil.  Sit it in the back of a dark cupboard for 4-5 weeks.  Strain.  You can place the jar in the sun each day to apply some heat.  When I make an herb infused oil from St. John’s Wort, I place the bottle on my back patio to soak up the afternoon sun.

Using the crockpot.

I put the herbs in the bottom of the crockpot.  Add the oil.  I stir everything together to ensure that the oil coats the herbs.  Turn the crockpot to warm.  Wait.  Occasionally I check on the mixture to make sure the herbs are still covered, and the temperature is at 100 degrees.  The more stable that the carrier oils you have chosen and the lower the heat – the longer you can infuse the oil.  I have read that some herbalists hot infuse their oils for days.  I would not do this.  If I wanted a long infusion process, I would use the crockpot to begin. I would then cold infuse the mixture for however long I wanted.  With the heat I keep the herbs in the oil for 5 hours.  I feel this is long enough.

Straining.

Turn the crockpot off and let the oil has cool.  Time to strain. To start I use an unbleached cotton muslin jelly bag.   I attach it to the mouth of a wide mouth jar (a hair elastic works great for this).  Scrape the oil/herb mixture into the bag.  I let time and gravity do the work.  Once the oil has drained through the bag, I use a large spatula or my hands to press as much of the remaining oil out of the marc as possible.

To remove any fine particulate matter, I strain the oil again, this time through an unbleached coffee filter.  I have found that lining a funnel with the coffee filter works best and cuts down on fiddling.  If I was feeling fancy, I could siphon the oil off the top – leaving the sediment at the bottom of the container.  It’s a judgement call depending on how much sediment I see in the oil.  The elderflowers had a lot of pollen.  I will filter it through a coffee filter a second time.

Bottling.

When the oil is filtered to my satisfaction, I bottle it in a dark bottle and label it with the herb, the oil, and the date I made it.  I add 5 ml of rosemary extract for every 250 ml of oil.  This helps to keep the oil from going off.  Vitamin E is an alternative.

With oils the main concern is oxidation.  You’ve seen how apples or avocado will start to turn brown after you cut them into slices?  That is oxidation.  An herb infused oil will last anywhere from 6 months to 3 years.  It depends on the oils you use and the storage conditions.  I bottle the oils in a dark bottle so that less light can get in.  I store my oils in a cool dry and dark cupboard.  If I had made a product with a more unstable oil, I would consider keeping the finished product in the fridge.

Herb Infused Oils.

Every herbalist has their own way of making oils.  The best way to find what works for you is experimentation.  My method works for me.  Now that I have the elderflower oil made I am going to find that face cream recipe and work on that next.