How to determine if your edible oils are rancid
Mar 2, 2020
Article
Rancidity is the process through which oils and fats become partially or completely oxidized after exposure to moisture, air, or even light. Though not always that obvious, foods can go rancid long before they become old. For oils, whose antioxidant properties are highly valued, such as for olive oil, this is especially problematic. A simple (and free) test for rancidity of oils can be performed at home using your own analytical instruments: your senses of smell and taste.
- Pour a few milliliters of the oil into a shallow bowl or cup, and breathe in the scent.
- If the smell is slightly sweet (like adhesive paste), or gives off a fermented odor, then the oil is probably rancid.
- A taste test should be performed to be sure, since some oils may have a naturally sweet scent.
- Ensure the oil sample is at room temperature, then sip a small amount into your mouth without swallowing. Similar to tasting wine, slurp air across the oil in your mouth, then exhale to determine if the oil has flavor.
- If the oil has no flavor, it is most likely rancid. Do not consume it!
Once food has turned rancid, there is no way to go back and fix it. So, if you find out by means of the sensory test that the oil is rancid, it is already too late. For those of us who would rather skip this step to avoid having rancid food in our mouths, the possibility to accurately predict the future oxidation behavior of edible oils would be great. In fact, this is exactly what the Rancimat from Metrohm can do if you follow our tips and tricks in this article.