Fluorinated, ceramic and other coatings for frying pans - which option would be the safest?

This article was first published in Finnish in March 30, 2023: Paistinpannujen fluoratut, keraamiset ja muut pinnoitteet - mik? vaihtoehto olisi turvallisin?

Non-stick coatings are used widely in cookware, such as frying pans, pots, pans and baking tins. The purpose of the coatings is to prevent food from sticking and to facilitate cleaning.

There are basically two types of non-stick coatings: fluorinated and ceramic. Fluorinated coatings are made from substances that belong to the group of PFAS compounds, i.e. per- and polyfluorinated alkyl substances. These are suspected to weaken children's immune response and may also cause elevated cholesterol levels and affect liver function, susceptibility to inflammation and birth weight.

Finns are exposed to PFAS compounds mainly through food, but it is not known how much non-stick cookware contributes to the intake. However, PFAS compounds are known to be released from cookware during their manufacture, use and disposal, so fluorinated coatings are considered to be a health risk to some degree.

The non-stick coating works better the lower the surface energy is achieved. For example, the surface energy of PTFE (polytetrafluoroethylene) is 19 mJ/m2, stainless steel about 40 mJ/m2 and cast iron about 1500 mJ/m2.

PTFE coatings

PTFE, or polytetrafluoroethylene, was invented by accident in 1938. A DuPont employee, Roy J. Plunkett, discovered during his other experiments that tetrafluoroethylene gas, catalyzed by iron in the container walls, had polymerized. DuPont registered PTFE under the trademark Teflon in 1945. At first, it was expensive to manufacture and difficult to shape. However, the manufacturing technology progressed and in 1954 the French engineer Marc Grégoire - at the suggestion of his wife - decided to use Teflon as a coating in frying pans and founded the Tefal company. Today, there are hundreds of manufacturers of PTFE-coated containers.

For a long time, Teflon manufactured by DuPont was made from PFOA, but its use was banned in the EU in 2015. DuPont replaced the PFOA used in the manufacturing process with a group of other perfluorinated compounds, which it collectively refers to as GenX compounds, but the safety of these has also been questioned. In 2019, GenX compounds were added to the list of substances of very high concern (SVHC) of the REACH regulation in the EU. Chemours, a subsidiary founded by DuPont in 2015, appealed the decision to the European Court of Justice, which however rejected the appeal.

By GenX compounds, DuPont-Chemours refers to the starting substances of the manufacturing process, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoic acid (HFPO-DA), its ammonium salt, and the transformation product, heptafluoropropyl-1,2,2,2-tetrafluoroethyl ether, generated through decarboxylation. All three compounds contain fluorine and therefore belong to PFAS compounds. GenX compounds are persistent and potentially bioaccumulative.

During cooking, small particles may come off from PTFE coatings, but these are likely to be excreted from the body with feces. When heating the pan, harmful compounds can also evaporate from the coating and be inhaled. However, it is unclear whether the amounts released during cooking are significant in terms of exposure and health compared to other PFAS exposure.

GenX compounds are not thought to be very toxic, but especially their long-term effects are unknown. PTFE coatings therefore still cause concern about health risks. Due to potential health risks, the EU is currently preparing a complete ban on PFAS compounds, which is estimated to enter into force in 2025.

Ceramic coatings

Ceramic coatings are marketed as a safer alternative to coatings containing fluorine. Considering the ingredients they are made of, they are probably safe to use.

Despite their name, ceramic coatings (e.g. Cerasafe) are not ceramics, but coatings that are made with a so-called solution-gelation i.e. sol-gel polymerization. In polymerization, a sol-gel mixture, i.e. a colloidal mixture formed by nano-sized silica (sand) and liquid, is sprayed onto the desired surface, after which it is cured at very hot temperatures.

The ceramic coating isn't exactly non-stick either. The sol-gel mixture is released from the coating when heated, which gives the impression of non-stickiness. The ceramic coating slowly wears away completely, and the service life of ceramic pans is therefore only 1–2 years.

Alternatives to non-stick coatings

Cast iron and carbon steel are safe materials for frying pans. Small amounts of iron can be released from them into the food, but this is not harmful to health.

Stainless steel is also a very safe material for cooking. It can release very small amounts of nickel and chromium, which may cause allergy symptoms for the most sensitized people.

Weighing risks

Whichever pan you choose, remember that in the end, what impacts your health the most is the type of food you fry in the pan.