I’ve been storing homemade herb oil at room temperature for a while, is it still safe to use?

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Generally we do not recommend storing any homemade infused oils at room temperature for long due to safety concerns.  Homemade flavored oils (particularly garlic oils according to the FDA, but also possibly other flavors) can grow botulism bacteria.

Don’t let that stop you from making flavored oils, but for safety’s sake:

          ● Make them in small batches. 
          ● Always store them in your refrigerator.
          ● Use them up quickly. 
          ● Use store-bought garlic oil rather than making your own. 

Commercially made flavored oils are often treated and/or manufactured in a way that makes them safer.  Just store them according to the manufacturer’s instructions.

Our preferred herb oil method
is quick, easy, and actually blends fresh herbs right into the oil, so it’s ready to use right away without infusing…why not just make it as you need it?

Homemade flavored alcohols and vinegars are very bacteria-unfriendly places and thus generally safe to store at room temperature.

Related Posts:
How to Make Herb Oils
How to Make Chile Infused Vinegar
How to Make Chile Infused Alcohol
Roasted Beet Oil Recipe

– Question Submitted by Tom

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2 Responses to “I’ve been storing homemade herb oil at room temperature for a while, is it still safe to use?”

  1. 1
    Bradley says:

    Why is infused oil so susceptible to bacteria if, as you say on the website in reference to the fat in confit and the fat layer on top of stock acting as a preservative, that bacteria do not like fat?


  2. 2
    Matthew says:

    Hi Bradley,

    There are a couple of reasons infused oils are a concern. First, people don’t tend to refrigerate them, unlike the two examples you note: confit (assuming it’s not canned/jarred) and stock. Secondly, people tend to hold on to flavored oils for extended periods, on the theory that the oil will draw out more flavor from the infusion ingredients.

    Finally, some ingredients people use to flavor their oil can already contain botulism spores, presumably from the fields they were grown in (the FDA has singled out garlic as the most likely oil flavoring to carry them). Botulism spores naturally occur in soil. Many, if not most people do not cook the ingredients they use to flavor their infused oils, so the bacteria is not killed before it enters the oil (unlike anything on the duck legs in confit or the bones/vegetables in stock). Botulism does not require oxygen to survive and produces neurotoxins that persist in the growth medium (your oil) after it dies.

    As a side note, stock’s fat layer only helps preserve it. Stock is a bacteria-friendly environment, and thus pretty perishable, even with the fat cap. It should be discarded after 2-3 days if fresh (freezing will make it last several months).