Thursday, November 19, 2009

Stick with it

Dear reader, the purpose of the present installment is to convince you that you should not be using non-stick cookware. After briefly reviewing the history of non-stick coatings, I present two distinct lines of argument against their use in the kitchen - particularly on frying pans. First, I examine the potential health hazards related to the use of non-stick coated pans. Secondly, and more importantly, I examine the disadvantages of using non-stick cookware from a perspective of culinary practice. I conclude by suggesting an alternative to synthetic non-stick pans that avoids both the hazards they entail and their practical shortcomings.

Frying pans with a non-stick inner surface are ubiquitous. You probably have one of these, dear reader, as I once I did. The material used to create most of non-stick cookware surfaces is polytetrafluoroethylene (PTFE), invented in the US in the 1930s and marketed under the Teflon trademark. Being highly non-reactive, Teflon was originally used for coating containers and pipes for reactive or corrosive chemicals. Due to its low-friction characteristics, it was also used (and continues to be used) as an ingredient in lubricants.

It was not until the mid-1950s that Teflon was first used for cookware. A French engineer found a way of binding Teflon to aluminum and produced a frying pan under the Tefal brand name (Tef from Teflon, al from aluminum). Aluminum is lightweight and has good heat conductivity but is highly reactive, making it a less than ideal material for cookware on its own. Coating it with the chemically inert Teflon solves the reactivity issue. The result is cheap, lightweight cookware with good heat conductivity and a surface to which food does not adhere during cooking, allowing less fat or oil to be used. As a further advantage, cleaning the Teflon coated pan is much easier than a conventional pan. At face value, a miracle product.

In recent years, this miracle has been the subject of scientific scrutiny. Research has found that, when heated to high temperatures, PTFE gives off toxic fumes. PTFE begins to deteriorate and release the said fumes at temperatures above 260°C (500°F). The fumes that are released have been shown to be lethal to birds and, at the very least, to be nauseating to humans. This is why most manufacturers warn owners of non-stick pans not to use them on high heat.

Even if you don't leave your non-stick pan empty on high for a while, you are still quite liable to heat its surface to temperatures above 260°C on a conventional stove. The probability of exposure to the fumes it releases is therefore high, if not imminent. Though there is no conclusive evidence as of yet, there are good reasons to suspect that repeated exposure to fumes from PTFE could pose a health risk to humans. One of the principal chemicals given off by heated PTFE, perfluorooctanoic acid (PFOA), has recently been classified as a ‘likely carcinogen’ by the US Environmental Protection Agency. In the absence of conclusive evidence, I suggest that it is better to err on the side of caution and avoid PTFE coated cookware altogether.

The health question aside, from the perspective of culinary practice, there are many things you simply cannot do with a non-stick pan. For starters, for the reasons mentioned above, the use of non-stick pans at high temperatures is inadvisable, which effectively prevents their use for searing and stir-frying, both of which require extremely high heat.

Other limitations of non-stick pans are related to how foods interact with their surface. A non-stick pan’s low adhesiveness can limit the surface area of the food that comes into direct contact with the pan’s inner surface. As a result, the food in the pan is cooked by radiation rather than by contact. Contact with the pan is essential for various processes, such as searing, browning, and especially caramelization. Caramelization, which involves the slight burning of naturally occurring sugars within fruit or vegetables, is an indispensable process in certain recipes. One such classic recipe is French onion soup, whose characteristic taste and colour depend crucially on the caramelization of onions. I have tried making onion soup with a non-stick pan and it was an absolute failure. The onions shrank and began to dry up but just did not want to caramelize – or at least not within the amount of time they usually would on in a conventional pan.

Some sticking to the pan, or coating the pan with a brown residue, is actually quite desirable in many cases, especially where cooking meats is concerned. An elementary step in the preparation of many sauces for meat is the deglazing of a pan in which meat was fried or roasted. Deglazing, for the benefit of the uninitiated, involves pouring wine or another liquid in the pan and using it to dissolve the caked on residues from the meat. These residues, full of caramelized sugars and broken down proteins, are a goldmine of rich, meaty, umami flavour (see article), not to be wasted under any circumstance. You will find no such treasure at the bottom of a non-stick pan, dear reader.

An inexpensive alternative to non-stick coating is cast iron cookware. With use, the inner surfaces of cast iron pots and pans become ‘seasoned’ – i.e., coated with a waxy layer of residues from fats and oils. This waxy layer acts as a natural non-stick (or at least limited-stick) coating. Making delicate things like omelets and crepes on a well-seasoned cast iron pan is just as easy as in a non-stick pan, provided that you follow certain basic rules. These include the following:
  • Thoroughly heating up the dry pan. Do not add fats or oils until the pan is hot.
  • Not moving the food for at least a minute after placing it in the pan – that is, unless you are stir-frying. Avoid the temptations to push the food across the surface of the pan or jamming the spatula under the food. Many foods will initially seize to the bottom of the pan but will eventually come unstuck once they heat up.
  • Cleaning the pan with hot water only. Use a non-metallic brush to scrub any residues off of the pan. Using soap and metallic brushes or scouring pads can remove the seasoning from the pan and, as a result, make it stickier the next time you use it.
Another good practice includes letting your food warm up to room temperature before frying.You can do this simply by taking your food out of the fridge half an hour before cooking. This is especially critical for meats. Most meats are cooked when they reach an internal temperature somewhere between 70°C and 90°C. Warming meat up from refrigerator temperature (4°C) to room temperature (usually slightly over 20°C) makes a big difference. It will help the meat sear better when it hits the pan and will prevent its juices from leaching out. Moreover, it will allow the meat to reach the desired internal temperature faster, reducing the risk of over-drying or burning the outside before the inside is sufficiently cooked.

A new 25 cm (10 in.) skillet – the size that I use the most often – can be purchased at the likes of Canadian Tire for $25. If you go to any flea market, you are bound to find one for even less. Price is not the only advantage of buying used cast iron pans – they are likely to already be well-seasoned. If you pick up a new pan, you can pre-season it yourself coating the inner surface with a thin layer of cooking oil using a paper towel and then putting it in a hot oven for 20 minutes or so. You should repeat this a few times before using the pan for the first time – even if the manufacturer claims that it is pre-seasoned. Be patient the first few times you use your new pan – it will develop its natural non-stick properties only after a few uses.

Good appetite.