How to infuse herbs into oil: Hot and Cold Method

Written by Amanda Klenner

herb oil infusion pic

How to infuse herbs into oil: Hot and Cold Method

Once you have chosen the herbs and oils that are beneficial for the project you have in mind, it is time to infuse the herbs into the oils. How to infuse herbs into oil: Hot and Cold Method

There are two primary methods of infusing herbs into a fixed oil. The hot oil infusion method is quick and relatively painless, and the cold infusion method which takes 6-8 weeks. I have been taught that the cold infusion method is more medicinally beneficial, but after working with both cold and hot infused oils, I find each method has its own pro’s and con’s. I tend to tell my students to use the method that fits best for their lifestyle. I personally use low heat for the first 12 hours, then cap and seal the oils (as long as I am infusing a dry herb and not a fresh herb) and let it sit for an additional 4-6 weeks. The color and fragrance are both so rich when you do it this way that it has become my favorite. You can feel free to decide a favorite method for your self.

The cold infusion method is wonderful for both fresh and dried herbs. Dry herbs tend to make more potent oil and there is less of a chance of rancidity. Fresh herbs have a higher
water content, which can lead to rancid oil or mold issues, so special care should be taken when infusing fresh herbs in oil. I tend to usually work with dry herbs, but when herbs like St. John’s wort, arnica, and chickweed are in season I will definitely make some nice fresh infused oils with them.

 

Cold Infusion Step-By-Step Instructions

Ingredients:

  • Fresh or dry herbs
  • Oil of your choice
  • 1 quart (or smaller) mason jar or pyrex bowl.
  1. Harvest your herbs during the cooler part of the day, from a clean place without pesticides, herbicides, or animal feces. Be sure they are dry. Do not rinse the herbs. OR – acquire the dry herbs and measure them out to take up about half of your glass infusion container.
  1. Place the fresh or dry herbs in a sterilized dry glass jar. I run mine through the sanitizing cycle in the dishwasher and make sure they are thoroughly clean and dry before putting the herbs in. If you are using fresh herbs, let the herbs wilt for 24 hours before placing them in the jar. Once they have wilted, fill the jar ¾ full with the fresh herb, chopped. Sanitize a rock or fermenting crock weight and place it on top of the herbs so they don’t float to the top when adding oil. If you are using dry herbs fill the jar approximately half way with the dry herb, cut and sifted.
  1. Cover the herbs completely with the carrier oil of choice.
  1. Use a wooden chopstick or something similar to push the herbs under the oil and release all the air bubbles. You may have to do this a few times during the first day. For fresh herbs: Some herbs will float to the top for the first week or two. Be sure to keep them completely submerged under the oil to reduce the risk of the oil going rancid or moldy. This may require a lot of poking at them but eventually they will sink below the oil line. For dry herbs: Put a lid on the jar and don’t worry about it.
  1. Top the jar completely with olive oil leaving about an inch of oil over your herb matter.
  1. If you are using dry herbs you can screw a lid on the jar and set it in a sunny window. If you are using fresh herbs place some cheesecloth or a coffee filter over the top of the jar and secure it with a rubber band. This will allow the water from the herbs to evaporate and escape from the oil, decreasing your chance for rancidity.
  1. Place your jars in a sunny, warm, but not too hot, location and allow the warmth and sun to aid in the infusion of the oils.
  1. Label the jars with the exact date you started them and let them infuse for 4-6 weeks. Fresh herbs shouldn’t be left in the oil for longer than 4-6 weeks. Dry herbs can be left in the jar until they are ready to use.
  2. Using a fine mesh filter lined with cheesecloth, filter the herbs from the oil into a separate glass jar.
  1. If you used fresh herbs, allow that oil to sit covered with breathable barrier again for a day or two. After that time check the bottom of the jar to see if any water has collected on the bottom. If so extract the oil from the top of the jar, leaving the water with a thin layer of oil on top to be discarded.
  1. Decant your finished oil into a cobalt or brown colored jar to protect from UV damage, or in a mason jar and stored in a cool, dry, dark place.
  1. You can add some vitamin e oil to help extend the shelf life. You can also add a few drops of myrrh or rosemary essential oil to extend shelf life and protect from rancidity.

Herb infused oils need to be stored with a tight fitting lid in a cool dry place out of the light. If they are stored properly, the can last as long as the oils expiration date. Be sure to label your oil with the date you made it so you know when its shelf life will end.

Hot Oil Infusion Step-By-Step

Infusing herbs into oils with heat takes less time, reduces the chances for fresh herbs to turn the oil rancid or moldy, and extracts more volatile oils and color. It is a good choice for a quick project if you just don’t have the time to wait for the cold infusion method. I find it to be simpler, and easier for beginners who really enjoy the instant gratification of a job well done.

Ingredients:

  • Heatproof Mason jar, Pyrex bowl, or double boiler.
  • Oil of choice
  • Herb of choice (fresh or dry)
  • Double boiler or old pot you won’t use for food any more (I use our old non-stick pots that I refuse to cook with any more)

Directions:

  1. Place the herbs in the sanitized jar, bowl, or double boiler as you would in the cold method.
  2. Pour oil in the jar as you would the cold method, being cautious not to add oils that denature easily in heat like rose hip seed oil – that can be added later after the infusion into the predominate fixed oil is complete.
  3. Add water to your double boiler or old pot, about 1/3 up the pan. You want to be sure that when the jar is placed in the water, it has water up the sides, but you don’t want any water to come into contact with your oil.
  4. Place the double boiler or old pot on the stove and turn the stove on low. The water should be steaming but not simmering or boiling. Ideally, you want the water under 170 degrees. Some people can do this in crock pots, but mine runs way too hot, even on low, and burns the herbs, so I don’t use this method.
  5. Place the jar into the water, being sure no water will get into the jar/bowl. Double boilers don’t have this problem.
  6. Allow the jars to sit in the warm bath for 12-24 hours, being sure the water never runs low, as that can crack the jar and destroy the herb, and never gets too hot, again avoiding burning the herb.
  7. Allow the oil to cool to room temperature and strain and storing as described above.

Amanda is a Clinical Herbalist, Holistic Nutritionist, and Health Coach located in Westminster, CO. She is also a mother, wife, and avid dog lover (cats are ok too). She has a passion for teaching people about the beautiful herbal medicines we can work with to maintain health, wellness, and joy. She is the publisher of Natural Herbal Living Magazine, works with people clinically to help them reach their health goals, and makes a line of organic, handmade herbal products.

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Comments

  1. A great overview of how to infuse herbs into oil. It’s good for those just getting into using herbs to know how to do this. Thanks so much for sharing!

  2. I’ve used the solar method many times in the past, but I read an article that said the solar method causes botulism. Does anyone know if this is a fact? I really love using the solar method and would like to continue using it. I will do some more research, but until I can get some clarification as to whether the solar method causes botulism, I will use the stove top method.

    • The botulism is more of an issue with garlic than it is anything else, but it is always good to play it safe. I have found that many herbs will also turn the oil rancid or grow mold if they aren’t properly submerged, which you can smell. Unfortunately botulism doesn’t let off much of an identifiable smell. It does cloud the oil, but so do resinous herbs. That being said, the solar method is the traditional method, what I wonder though is, if traditional healers infused fresh herbs into oil, or dry. I often use dry herbs in oil using the solar method, so I don’t have to worry about botulism. The only herbs I *HAVE* to do fresh are St. John’s Wort and arnica, plantain is nice fresh too. Also, if people aren’t eating the oil, botulism is less of an issue, and if the oil will be heated while making product, like in salve making, the botulism will die. It dies at 120 degrees. I hope this helps.

  3. I tried the hot method, and burned my herbs I think. Toasted them at least. Is the oil salvageable at all? Or do I need to start over?

    • What herbs did you toast and what are you using it for? Usually if you are doing a body butter or something like a topical application, that isn’t medicinally intended, you can still use the oil. Burnt chamomile, for example, smells very nice (like sugar cookies), and I would use it like a body butter. Generally, it will be slightly less medicinal, but still useful. Next time, try keeping the heat down and the water full, and they shouldn’t burn.

  4. Dear, I have a question…I have used rose petals and hibiscus. Started with cold infusion and after about 2 weeks I decided to try and heat them (while adding few more rose petals as well) so than I can put It back for the next few weeks. The reason I done that is that I did not get any sort of color from the petals, and hoping that incorporating hot infusion will help that a bit.
    Am I impatient , or is it the herbs ? I use olive oil and It looks almost exactly same color wise , but has a nice rose’ish smell.

    I want to get a red colored oil (if not dark red, at least reddish…). How do I do that?
    The oil will be used for diy makeup so I don’t mind anything, just to get the color out ;_;

    • Hi Vi,

      Generally, hibiscus and rose don’t release their pigments very easily. I tend to use a fine hibiscus powder when infusing it in oil, with coconut oil, using heat if I want color. Still, that gets you a light pink. You can leave a bit of powder in the oil, depending on the color you are hoping for (more red=more hibiscus powder). That works well for lip balms, but not as well for body butters, since it leaves a bit of a gritty texture. You can also look up cosmetic grade micas for coloring (mineral colorants). The pigments in hibiscus come out better in water, so if you are making a lotion with water, you can use the tea as your water base, but you might need a preservative so it won’t mold.

    • Hi Vi, I used Alkanet Root to change my oil to red. It changes quickly so if you are looking for a pink then you don’t need to infuse long, but if you want a deeper red then keep infusing for a few days.

      Good luck

  5. I just made a jar and put it in the room that gets the most sun, but I worry it isn’t enough sun or warmth. It is winter here so even with our mild winters, I’m not sure if sitting them outside is a good idea or not. Any advice on what would be best? It’s been in the 50s and 60s lately except at night. The house is about 70.

  6. Hello! Bit of a long one, here. I’ve done some infusing before (just started last year), but they were very simple since I was just starting out, and this year I want to try again, but I’m going to be using different oils and herbs in combination for different uses, so I’m a little out of my depth, ha! I really only need to clarify a few things that I couldn’t find out myself.

    1. Herb ratio.
    Not herb to oil ratio, but rather herb to herb. Should I use equal amounts of whatever herbs I’m using for infusing? Or use more of a specific kind for my desired effect? For example, I want to use Calendula and lavender in my tattoo salve, do I use more calendula or lavender, or does it really not matter?

    2. Oils.
    I mainly use sweet almond and babassu oil. Should I infuse each oil separately (I’m leaning towards this method), or is it okay to combine the two oils and then infuse them?

    3. This is more of a side question, but have you ever infused babassu oil? Or know anything about infusing that particular oil? I’m fairly new to it (so far, I’ve only infused almond, coconut and avocado)

    Sorry for the barrage of questions! I really couldn’t find any answers to these and I’m just trying to cover my bases before I start on a new project.

  7. Hello! I found your blog post and I really like your instructions, I learned a lot. I have a question about an oil-infusion problem I had, and I can’t find what happened with it. I had a jar with fresh rosemary left to macerate in olive oil, and I had a jar with sage left in sunflower oil. Both the fresh herbs had been washed, dried, but not left to wilt. I also left them for longer than the 4-6 weeks (more like 12 weeks). They were topped with a cloth fabric and left in a cool dark place.
    When I was ready to use them however both the jars had a kind of mucus layer on top of the oil. Kind of slimy, transparent. When I removed the oil the layer dried to a brittle thin film between the branches of the herb. The oil smells fine and looks fine. But, what happened? Have you seen this in your infusions? I assume it is some kind of bacterial growth, but I would like to know more.
    Also, I’m assuming I should toss the oil?

  8. I am concerned about infusions of dry herbs I have had “soaking” for 12-18 months. How long is *too* long for herbs in well sealed, glass jars, dark and cool storage. I originally made salves and massage oils for friends and family, however, due to life changes, I can’t possibly divest myself of the number of jars of salves and oils all my infusions would create. Am I able to take only the amount of infused oil I need for a few jars of salve at a time and allow the remainder to continue infusing?

  9. Okay, I’ve done herbal infusions many times but I made a boo boo on this one. Basically, long story short, my herbal infused coconut/olive oil got mixed in with some water. I know water can make it go “bad” from what I’ve read. Is is salvageable at all? Can I make something else so I don’t waste the whole infusion? Can I put it in fridge for oil and water to separate and put the oil in separate jar? Please help, I hate for it to go to waste!

    • Hi Kirstie,

      You can let the oil and water separate, and very carefully pour the oil off from the water. I pour it into a clear measuring cup so once it settles, I can look at the bottom and see if there are any other water bubbles. If there are, I will keep pouring it off until no more water bubbles are in my oil.

  10. I see you mentioned the slow cooker. I have a warm setting on mine. My herbalist teacher said to keep it in the warm bath, but I forgot what she told me as far as how far the water should come up to the ball mason jar and for how long to let it steep in the crockpot on warm.
    Can you help me with that?

    Thank you,
    Jill

    • Amanda tell you how long in #6 of her instructions above,

      Allow the jars to sit in the warm bath for 12-24 hours, being sure the water never runs low, as that can crack the jar and destroy the herb, and never gets too hot, again avoiding burning the herb.

      Good luck !

  11. Hi
    have you ever infused mushrooms like Reishi or Chaga?
    Is that done using a hot process? i am tempted to try it with olive oil.
    any ideas would be welcome.

    • Hi Sylvie,

      Mushrooms work better as a water extract, because most of the medicinal components are water soluble. Typically, I don’t infuse them in oil because I feel like it would be a waste of perfectly good mushroom. A better way to work with mushrooms is to make a decoction (simmer it in water for 15-20 minutes, then put the decoction and mushrooms in alcohol (equal parts in volume of alcohol to your decoction) and let that soak for 6-8 weeks, then you have a strong double extract of mushrooms that is a powerhouse for health. Another fun thing to do with mushrooms is to make a strong decoction, and let it simmer down to where it is a thick paste. Dehydrate the paste and powder it, then you can add the concentrated powder to drinks or soup broths easily.

      I hope it helps.

      Blessings,

  12. Thanks for the article. I have found a unit for infusing that does the heating and timing itself, all you do is set the time & temp. It’s sold online, it’s called the LEVO Infuser @ www/levooil/com. Higest temp is 200° and time is up to 24 hrs. It has a stainless steel mixing resivor which is simple to load & clean. Unit works great, only problem I see, is it doesn’t have a large herb holder (1/4oz) usually is max depending on the herb. For accurate infusions however you can’t beat it. Enjoy

  13. Thanks Amanda for sharing your information and experience. I am about to make a oil and balm to soothe tender heart and nervous system using dried herbs: rose,Damiana and California poppy.
    I am confused if I should leave the steeping herbs in a hot spot or in a cool dark place. Herbalists seem to differ on this point. My guess is that either is fine but the cool dark process will take longer?
    Please advise

  14. I have just ordered an elemi resin for oil infusion. I am wondering if I can use the hot oil infusion for this? Thanks!

  15. I have dry wild Arnica flowers…..you mentioned that you only infuse fresh Arnica. Will dry Arnica get me effective oil?

    • If they are freshly dried you will still get some medicinal value from them, but not as good as fresh arnica flowers. Unfortunately, not everyone lives where arnica grows, or not everyone can get enough fresh arnica to last the year. If it is dry wild arnica flowers that were harvested in 2018, you should still be good to go.

  16. Hello there from Malaysia! 😀

    Great article you have here.

    Had a question for you though. I read in a website,saying that if you use the hot method (the slow cook method) you will need to open the mason jar lid. Seems like the reason for that is to ensure that no evaporates once you’ve done.

    Is it really true? Or should i just put on the jar lid and let it in the slow cooker?

    Thanks Amanda!

    • You want to leave off the jar lid if you are infusing fresh herbs so the water from the herbs can escape, which keeps your oil from going rancid quickly. With dry herbs, it doesn’t really matter.

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