Stainless steel, cast iron, ceramics, aluminium, wood… All the materials that populate our cookware are not equal in terms of resistance, workability, durability and health impact. Bernard Petit, chemical engineer and head of campaigns for the Réseau environnement santé (RES) and Dr. Laurent Chevallier, a nutritionist.
Cooking utensils: materials to be preferred
Stainless steel: the best!
An alloy of iron, chromium, carbon and nickel, it is the most widely used material in the chemical industry. This already says a lot about its degree of resistance and its total chemical inertia (absence of reaction/migration whatever the context). However, there are different types of stainless steel. The most common one for the kitchen is 10 /18 stainless steel. These figures respectively indicate the percentages of nickel and chromium, standards established by the European Union. It is also possible to find stainless steel 18/0, nickel-free. The latter is a little less robust, but a healthy snack for nickel allergies. “In any case, stainless steel remains a safe value from a health point of view. Moreover, it is unbreakable, easy to maintain and 100% recyclable”, assures BernardPetit, chemical engineer and member of the RES. But if you find that food clings more to the stainless steel, “add a little oil to the bottom of the pan, it will limit this effect and also allow a better distribution of heat, for a more beneficial cooking to the food”, advises Dr. rChevallier, a nutritionist doctor.
Our favorite stainless steel pans : Set of 3 Ingenio Inox Pans
Borosilicate glass (Pyrex): irreproachable
Another very good student who, like stainless steel, has easily found its place in the chemical industry thanks to its degree of solidity coupled with its perfect inertia. So in the kitchen, no problem either. Borosilicate glass, popularized by the Pyrex brand, can withstand temperatures of up to 500°C without side effects. It can just be reproached for being more fragile than other materials. If it falls, it breaks. It can also lose its shiny appearance after a few passes in the dishwasher. (But that’s a real hassle!)
The Pyrex we love: Rectangular Pyrex baking dish – 27 x 17 cm
Cast iron as a friend
“That’s all there is to it,” as our grandmothers would say. And they are right! An alloy of iron and carbon, cast iron is not only a real must for gentle and long cooking, but it is also capable of searing food without any health risks. “It is a chemically safe material. Iron atoms can come loose, oxidation can also be observed, but this is of no consequence. Inertia can also be improved by an enamel coating, but only if the enamel is of good quality,” notes Bernard Petit.
If in doubt about the quality of the enamel, opt for natural cast iron. And for a quality product, prefer French brands, which comply well with European standards, unlike others. “We have already seen Asian manufacturers produce casseroles with cast iron radiators, containing traces of heavy metals,” recalls Bernard Petit. Other strong points are its durability and performance, which improve over time. The fats used on the cast iron end up patinating it (this phenomenon is called “culottage”), which favors the distribution of heat and increases the quality of cooking. Although expensive, cast iron is an investment that can last for decades. Its poor workability can however limit its use.
Our favorite cast iron dish: Cocotte ronde Invicta
Wood, a material of the future?
He was much criticized for not being hygienic enough. “But it has been shown that after traditional cleaning, bacteria do not grow any faster on wood than on plastic,” says LittleBernard. Today, however, it is one of the best materials to use for environmental protection. “In this period of ecological and energy transition, it should be favored over plastics, which come from non-renewable fossil oil sources. In addition, INRA publications (presented at the 2017 États généraux de l’alimentation) indicate that wood makes it possible to store CO2, and to reduce greenhouse gases, compared with oil production,” Bernard Petit explains. Be careful, however, to choose only utensils made of raw, natural wood, which has not undergone any chemical protective treatment. “The information on possible treatments is often insufficient, or even absent, so ask the salesmen,” insists Dr. Chevallier.
Iron, a little taste of coming back?
Fashionable among “ecologists” these days, this rather rustic material remains reliable from a health point of view. And it’s very cheap. The only problem is that it leaves a taste to the food (but without any toxicity). The problem can be alleviated by lining an iron cake tin with baking paper. On the other hand, in iron pans (which require a base), it is difficult to escape this little aftertaste. Cleaning is not so easy either. The ideal remains to wash the iron with hot water, to dry it well, then to apply to it a small blow of oiled rag. Notice to the maniacs of cleanliness.
Ceramics: less ecological than it seems.
Still recent in the culinary world, this material is an alternative to various suspect non-stick coatings. Thus, it is mainly found inside stoves, pots and pans, woks. Ceramic is composed of silica and water and would have the advantage, according to the manufacturers, of being able to be applied on kitchen utensils at low temperature (about 200°C), limiting CO2 emissions and allowing energy savings. Not so sure, however, that it is so environmentally friendly, because it deteriorates faster than Teflon. Another shadow in the picture: some manufacturers could use nanotechnology for their products.
Silicone, provided you choose it well.
Difficult to resist the silicone moulds, non-stick and playful to use in pastry making. Belonging to the family of elastomers (very flexible materials), silicone is made from silicon (a component of silica) which has been catalyzed either with platinum salt or peroxide salt. A difference in composition that is by no means insignificant and which will give two categories of silicone molds, platinum and peroxides, with their own properties. Indeed, platinum silicone is able to withstand temperatures between 250 and 300°C. Whereas peroxidized silicone becomes unstable from 160°C upwards, as highlighted by a DGCCRF(3) survey in 2004. To date, there is no ban on peroxidized silicone molds.
Prefer platinum silicone molds. These generally bear one of the following names: “Silicone”, “Platinum”, “Premium Silicone” or “Elastomer” and can withstand temperatures of up to 300°C.
Our selection of platinum silicone molds:
Tefal Proflex tart mould, from 10,99€. Mould 20 mini financial Mastrad, from 14,99€. Mould for 3 Ard'Time cakes, from 31,67€.
Kitchen utensils: materials to be banned
It was in the 1950’s that PTFE began to invest our frying pans. It was then difficult to resist its exceptional non-stick power. But today, the craze has given way to a certain disappointment. Because the scientists’ conclusions are irrevocable. PTFE is harmless at low temperatures and releases toxic compounds from 230°C, the temperature reached by a frying pan in five minutes of normal use. And above 350°C, it’s even worse, PTFE decomposes while continuing to produce toxic substances. Inhaled by humans, these fumes can cause the same symptoms as the flu. Finally, to glue this coating to the pan, it is common to use PFOA (perfluorooctanoic acid), a carcinogenic substance that can migrate under certain thermal conditions.
Aluminum, the bête noire
Legitimate in the automotive or aeronautic industry because of its lightness, the use of this material remains much more questionable in the culinary field, as many scientific studies have shown it to be overwhelming. For example, aluminum is partly associated with Alzheimer’s and Parkinson’s diseases. It is also thought to have endocrine disrupting effects. Common sense dictates that we limit our exposure to this metal as much as possible. But this remains difficult because it is naturally present in the earth’s crust. We are exposed to it in many ways, permanently, through food or water. “However, its assimilation depends on its physico-chemical form,” says Dr. Chevallier. “Aluminum is a metal whose chemical sensitivity poses a serious problem. It can react under certain conditions, such as cooking at high temperatures, and contaminate food,” explains Bernard Petit. So the rule is simple: “Aluminum should not be in direct contact with food during cooking. On the other hand, as it is an excellent conductor of heat, it is allowed to be present, in sandwiches, between two layers of stainless steel, in frying pans and saucepans”, says Dr Chevallier.