When you begin researching how to make herb infused oils, the most common method you’ll find on the internet is the slow or cold method, which includes instructions like…
“place your oil covered herb in a cool, dark location and let it sit for 6-8 weeks”
So, you follow those instructions, and at the end of that 6 (or 8 weeks if you can stand waiting that long) you filter your oil, only to find that it looks and smells pretty much the same as when you started.
What happened?!
While this may be the most common method you’ll find, it’s not the most effective.
In this blog post you’ll learn why some heat is actually beneficial for your herbal oil infusions.
Why is the Slow, Cold Method so Common
There are a couple of reasons why this method is so prevalent online.
- It’s easy
This method is shared the most because it’s a simple process, and you don’t need a lot of equipment. It’s perfect for the DIYer who’s just getting started and is using the oils on their own instead of in a formulation. If you’re just using the infused oils on their own or making salves with just a bit of beeswax added, then potency is not as big of a concern.
- Many believe that heat will damage the oils and compounds in the herbs.
I’ve found that some folks believe that using any heat will damage the plant compounds and oils they use to infuse.
Let’s dig a little deeper into this myth.
Myth vs Truth about Heat
Nearly every myth has a grain of truth to it, and the myth that states its bad to heat your infusions/macerations is no different.
The truth is… it is bad to subject herbs and oils to extreme heat. The problem is that over time, people have taken that key word “extreme” out and are now claiming that any heat is bad.
This is false when it comes to most plant compounds and many oils.
Oils
While there are some heat sensitive oils, we have a large number of oils and butters that are stable when subjected to heat. Most are stable with low heat, and there are a few which are stable even when subjected to high heat (think about our cooking oils such as olive oil).
This is why it’s important to choose a heat stable oil for your infusions/macerations. Jojoba, olive, and coconut oils are great examples of heat stable oils.
Herbs and their Compounds
Just like oils, there are many herbs that can be subjected to heat without damaging their compounds. Consider the herbs we use when cooking (such as spices), or the herbs we make tea with. The aromatic and therapeutic compounds which are extracted into soups and teas add aroma and flavor to our foods. We know they aren’t damaged because we can smell and taste them.
While there are a few compounds (such as minerals and mucilaginous compounds) which extract better under cold conditions, the truth is….
the vast majority of compounds actually extract better when some heat is applied.
The Benefit of Heat
When we infuse/macerate herbs into oils, we’re actually infusing the oil-soluble plant compounds, that are contained within the herb. These compounds are contained within the plant’s cells and must be pulled out.
So, how do we do that?
…by turning up the heat!
While there are a few factors that can influence the ability to pull out these compounds, temperature has a significant influence on extractions (with warm or hot temperatures increasing the extraction of most plant compounds).
There are a few ways that heat influences extraction.
- Heat can help break down the cell walls of plants.
- Heat increases the movement of the molecules within a plant’s cells. This increased movement helps pull the molecules out of the plant’s cells.
- Heat also helps the solvent (in this case oil) to more effectively break apart the bonds of a molecule and incorporate them into the solution with themselves.
A great example of how heat influences extraction can be seen when making tea.
When we make tea we use almost boiling water (175-195F typically). Most teas are made within just a few minutes using this method. But if the temp is too high, the tea turns bitter, and if you use a cold brew method, its going to take up to 12 hours before the tea is fully steeped.
Continuing with the tea making example…
If you try to add regular granulated sugar to a cold brewed tea, you’ll find that it takes quite a while to dissolve. On the other hand, if you add granulated sugar to hot tea, it dissolves easily.
In both cases, heat is used to help dissolve molecules more efficiently.
NOTE: I do want to mention that the guidance provided here on the use of heat is to help you extract the widest range of compounds possible. Different compounds extract best in different temperatures (a few even extract best in high temps), but since we’re trying to get the most compounds, not just a single compound, it’s best to keep your infusions at a low-medium temperature (125-140F / 50-60C) where most compounds are more easily extracted.
Summary
As you’ve seen, the idea that all herbs and all oils will be damaged if subjected to any amount of heat is a myth.
The key points to remember are:
- Choose heat-stable oils
- Avoid extreme heat
As long as you’re following these guidelines, heat is of great benefit when infusing/macerating your herbs into oils.
In fact, our ancestors used heat by placing their infusions where the sun would gently warm them.
Now, thanks to modern technology, we have the ability to apply controlled heat over a period of time to greatly enhance the extraction of herbs.
By choosing heat-stable oils and applying low, consistent heat, you’ll not only significantly increase the potency of your oils, your oils will infuse in less time too — a double win!