Will cooking in extra virgin olive oil ruin your cooking pans?
Sian Armstrong
There is a common myth in Australia that cooking with extra virgin olive oil (EVOO) can ruin some cookware, in particular non-stick Teflon coated (TC) pans. This belief is specifically supported by some manufacturers’ stating that oils with higher smoke points are more suitable for cooking with their TC pans, and that EVOO could be damaging to their coating.
There is NO technical evidence to support these claims.
The Olive Wellness Institute team often gets asked questions about this common myth, and the answer is NO, cooking in extra virgin olive oil will NOT ruin your non-stick pans.
There IS technical evidence to support it.
Myth-busting with science
In 2019, the experts at the Modern Olives Laboratory conducted research to assess the suitability of various cooking oils, including EVOO, for use on TC pans. This research well and truly busted the myth, and showed that cooking with extra virgin olive oil is perfectly ok for your pans.
Methodology
When cooking pans are heated, various reactions occur that may have the potential to either damage the pan’s quality, and/or leach chemicals into the cooked food. To investigate the hypothesis of whether cooking with EVOO ruins TC pans, the researchers measured the release of elements and metals from the pans when heated with different oils.
The following methodology was used:
- A model solution of water and vinegar (WV) was used to simulate the effect of cooking;
- Testing utilised three brands of different TC pans sold at varying price points (Pan A = least expensive; Pan C = most expensive);
- Each was heated with the WV solution to study the release of chemical elements before and after six cycles of heating with six different cooking oils;
- Each trial was done by triplicate, consistent with the method used by Lomolino et al (2016) that assessed mineral elements and metals released from cookware including TC pans.
Note: the assessment of release of metals and elements from pans to investigate chemical interactions that occur when a pan is heated is also supported by methodologies reported in other research publications.
Oils tested
A range of commonly used cooking oils available on Australian supermarket shelves was used for the purposes of the study: extra virgin olive oil (EVOO), olive oil (OO), canola oil (CO), grapeseed oil (GO) and rice bran oil (RO). Only one brand (different batches) of each oil was selected.
Elements tested
WV solution samples were tested for Aluminium (Al), Calcium (Ca), Chromium (Cr), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), Phosphorus (P), Strontium (Sr), Zinc (Zn), Silicon (Si), and Silicon Dioxide (SiO2). These are common metals and elements tested for in studies of a similar nature.
Results and discussion
When combining data for all TC pans, no statistically significant differences were found between the final WV solutions from pans treated with the different oils. This indicates there is no significant difference between the volume of metals released from the cookware when various cooking oils were used.
Hence, the various cooking oils had no effect on the pans’ integrity and quality when cooking.
Pan variances
However, differences of statistical significance for Calcium, Copper, Iron, Phosphorus, Zinc and Silicon Dioxide were observed between the different TC pan types. Higher values of these elements were observed in the most expensive pan compared with the cheapest TC pan. For example, Calcium average values (including initial and final treatment) in pan C were ~2.92mg/L vs ~1.75 mg/L in pan A and ~2.42 mg/L in pan B (Figure 1).
Reasons for these results are not known, however it is worth noting that the differences in values between pans are more significant than any difference between oil treatments.
When considering the analysis of the data for each brand of TC pan, the only statistical differences between initial and final treatments were with Phosphorus levels using rice bran oil in the average priced TC pan (4.7mg/L vs 2.5mg/L). Silicon dioxide was not detected before treatment and significantly increased using olive (1.1mg/L) and grapeseed (1.03mg/L) oils in the lowest priced TC pan.
Again, reasons for these results are not known.
Visual deterioration
After all treatments, no visual deterioration of any of the TC pans was observed.
These results are limited considering the lifetime of the TC pan, but they indicate no impact of the oils’ type on the integrity of the cooking pans and that EVOO is equally suitable to other oils under normal cooking conditions.
Conclusion
This research study provides scientific evidence that cooking with EVOO does not ruin non-stick Teflon coated pans at any different rate than other cooking oils.
Significantly higher differences in metal leaching were observed between pans, rather than between the treatments with the different oils. In no case, did the use of EVOO lead to the release of significantly higher levels of metallic substances from the pan than when using any other oils.
