With all the concern over forever chemicals showing up in our cookware, many eco-conscious home chefs are turning to silicone cookware. Is silicone a green and non-toxic option in the kitchen? Our overall verdict on silicone is a thumbs down, here’s why.
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When I first discovered silicone cookware, I thought it was too good to be true. I was baking a lot at the time and it pained me to use all those disposable cupcake cases and reams and reams of baking parchment. There was no way I was going to use toxic non-stick aluminum bakeware, and I hadn’t yet acquired any cast iron bakeware.
Silicone muffin pans and cake pans seemed like a dream, but even now I’m still not convinced of their safety. Before we get into my pros and cons for using silicone cookware, first what is the stuff, anyway?
What is silicone cookware?
Silicone is a synthetic ‘rubber’ that contains bonded silicon and oxygen and, in some cases, carbon. While these are natural elements and bonded silicon is abundant in sand and rock, silicone bakeware can contain all manner of other materials aside from oxygen, silicon, and carbon.
In general, silicone bakeware is heat-resistant, freezer safe, and oven safe, but only up to 428 degrees Fahrenheit or 220 Celsius. It shouldn’t be put in the dishwasher, however, and as it doesn’t biodegrade and cannot currently be recycled, it’s not exactly eco-friendly.
Silicone cookware also needs to be dried well before being stored, or it may degrade and develop discoloration and tackiness. I’ve had this happen to a couple of silicone cake ‘pans’, so I learned my lesson and store them more carefully. So carefully, in fact, that I rarely ever use them and should probably take them to the thrift store.
As you can probably tell, my overall verdict on silicone is a thumbs down, but there are some benefits, which we will get into now.
- Reusable
- Easy to clean
- Doesn’t biodegrade which is a major negative
- Can’t go in the dishwasher
- Not recyclable
- Has to be dried thoroughly before storing
- Very little actual safety research to verify silicone doesn’t leach
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The benefits of silicone cookware
Silicone cookware seems like a great alternative to non-stick muffin pans and cake tins.
And, unlike paper cupcake and muffin wrappers, silicone can be reused time and again. It is excellent for oil-free or low-fat cooking as it is non-stick and easy to clean, meaning you don’t have to grease the cookware before use. High-quality, food-grade silicone cookware is said not to affect the flavor of food, or react with food or drinks, and manufacturers claim that it doesn’t release any odors or toxic fumes during cooking.
Silicone cookware for kids
Silicone cookware is also fun and easy for kids to use. It typically comes in bright colors, different shapes, and is easier to handle than fiddly paper or heavier metal bakeware. You’ll notice a handful of silicon options cropping up in our roundup on kids’ dinnerware here. And, if you move house a lot, silicone bakeware is a heck of a lot easier than cast iron and ceramic bakeware to transport.
While we recommend silicone for non-toxic baby nipples, we do not recommend silicone baby bottles, preferring stainless steel and glass instead.
Why I stopped using silicone bakeware
Why did I stop using silicone bakeware? Well, in large part because I began to acquire cast iron and ceramic cookware that served much the same purpose and performed better. And, if I’m honest, because that ‘tacky’ feeling gave me pause.
You see, while manufacturers rush to claim that silicone is a great non-toxic cookware option, there’s not actually that much research on the safety of these products.
Is silicone cookware safe?
There’s very little to suggest that silicone cookware is unsafe, but there’s also not much to confirm its safety either. What’s more, there are huge variations in the quality of silicone cookware, with cheap, low-quality alternatives full of fillers and binders most frequently cited in concerns over odors and poor performance.
Purity test for silicone cookware
When buying silicone kitchenware, check that it is 100% pure food-grade silicone. This is the stuff that Canada’s health agency, Health Canada, maintains does not react with food or beverages or produce any hazardous fumes, and is safe to use up to recommended temperatures.
To test if your silicone bakeware is pure, give it a twist. If you see lots of white streaks, this suggests that there are large amounts of fillers in the silicone, which means it may not be suitable for use in cooking or baking.
FDA position on silicone cookware
The U.S. Food and Drug Administration (FDA) determined in 1979 that silicon dioxides (the basic elements in silicone cookware) were generally recognized as safe (GRAS) to use as food-grade materials. The first silicone cookware (spatulas) were sold sometime in the 1980s, but the FDA hasn’t conducted any follow-up safety studies on silicone cookware since.
Debates on leaching
Food-grade silicone cookware is typically coated in food-approved compounds or agents that help release food after cooking. There’s debate as to whether these coatings end up leaching into food, which isn’t helped by studies that use hyperbolic language and test conditions that don’t match real-life use, as discussed in this paper.
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What the research says about silicone molds
In one study, very limited migration of these compounds was noted from silicone baking sheets or from the silicone nipples of infant bottles (R). This study did not actually heat the silicone bakeware in an oven, though, which undermines the usefulness of the research for those intending to cook with silicone products.
Scientific research on silicone baking products
However, one study, published by the Swiss Federal Office of Public Health in 2005 looked at whether chemical substances were released from silicone baking moulds when they were heated to 200-220 degrees Celsius (the recommended limit for these products). They also tested the products up to temperatures of 280 degrees Celsius.
Up to 100 degrees Celsius, the samples showed low migration of chemicals from the moulds. This migration increased rapidly after moulds reached 150 degrees, however, with the samples reaching the exposure limit of 10 mg/dm2 prescribed by the Resolution of the Council of Europe in most cases. At higher temperatures, such as those typically used to bake a cake, migration increased even further. At 175 degrees, all samples showed high migration values (between 25.5 mg/dm2 and 49.2 mg/dm2).
In some cases, the levels of leaching chemicals dropped upon the third round of testing for a product. This suggests that manufacturers may not be properly ‘curing’ their silicone bakeware before sale and that it makes sense for consumers to heat any new silicone bakeware to 220 degrees Celsius without food for a couple of hours. Once it cools, wash the moulds thoroughly in warm, soapy water, rinse, and dry.
In another study, researchers found that non-tempered moulds with a high level of volatile organic compounds (1.1%) had considerably higher migration of siloxanes than the equivalent tempered moulds (R). Tempering is a process used to make silicone moulds stronger, harder, and more elastic.
Silicone cookware alternatives
Since I’m not totally convinced of the safety of silicone cookware, I recommend purchasing these kitchen products instead:
Lodge Cast Iron: Scoring 5 out of 5 leaves, Lodge cast iron cookware is versatile, robust, and a great investment. Read our full review here.
Corning Ware: Another 5-leaf contender, Corning Ware is easy to clean, non-reactive to acidic foods, and can be used for cooking, serving, and storing food. Read our full review here.
De Buyer Carbon Steel Frying Pan: Finally, another 5-leaf product to top off the list, this carbon steel frying pan offers excellent heat distribution for easy grilling, searing, and browning of foods on the stovetop (including induction), camping stove, barbecue, or in the oven. Read our full review here.
Silicone in summary
Given that there is so little safety data on the use of silicone bakeware, and the availability of other types of cookware that are non-toxic, eco-friendly, and safe, I’d err towards ditching the silicone. Ceramic cookware may be a worthy alternative. That said, if you make jellies, chocolates, ice cubes, or popsicles, silicone molds can be fun and likely pose little risk of leaching siloxanes into food. You might also want to use silicone molds to make candles or soaps.
Basically, as long as you’re not putting silicone in the oven (or the dishwasher), you’re probably fine to use these products. Just remember to ‘cure’ the silicone molds in the oven first and clean them thoroughly before using them for any culinary tasks.
As for silicone utensils, I’d suggest only using silicone spatulas for working with cool foods, such as dips and batters. For hot foods, metal, wood, or bamboo spoons, spatulas, and other utensils are best.
Thank you for this. I was looking to buy a silicone spatula for all round use, but confused by the maximum temperature use and the heat my iron skillet can reach. From what you say it seems that a silicone spatula shouldn’t really be used for extreme temperatures.
I may get one for wiping out the blender and cake bowls etc, but not use it in skillet or wok.
What bakeware do you recommend that is safe such as muffin tins?
Hi Laura,
Cast iron is a great choice for muffin tins! They’ll last you forever and cook nice and evenly. Silicone muffin tins are also a good bet, but you’ll need to make sure to clean these and dry them well each time, otherwise they can suffer in storage and aren’t much fun to use.
Hope this helps!
Leigh
ThanQ so much for such a detailed pros and cons.
Hi! Thank you so much for writing this article. I was trying to figure out if getting silicone moulds for making dog treats (in the freezer) would be a safe idea. Anything that i wouldn’t use for myself, i wouldn’t use for my dog, to keep her safe. This article was so helpful and I thought it had great information.
Thanks again!
Thank you for this excellent article. Finally, someone took the time to research the toxicity of silicone bakeware. I’ve always been suspicious of it so I was thankful to see your article.
Any specific thoughts about using the silicone egg poachers that seem so popular? Thank you for your informative website.
Hi Benton,
Given that silicone cures at 220 degrees Celsius and water boils at 100 (give or take, depending on your location!), I think the silicone egg poachers are likely a good option. As with all silicone though, you’d want to check it’s in good shape and make sure to wash and dry it well between uses.
Hope that helps!
Leigh
This article was so helpful! We just moved into a new house and my silicone bakeware has been in storage. I opened the box and really wondered if I still wanted to keep it, especially because my new kitchen is much smaller. So, you helped me decide what to do- it’s all going to the thrift store! Thank you so much!
Thank you for posting this article. You mentioned to cure the silicone bakeware in the oven at 220 degrees is but you didn’t mention if it’s 220F or C. Thank you so much and will wait for your reply.
Hi Philomena,
My apologies. I missed the Celsius from that specific mention of temperature. I’ve amended it now.
Thanks,
Leigh
Awesome article.. Scientifically sound, as should be. Well done!
Why is silicon not dishwasher safe?
I appreciate that you have this site, and will definitely refer to it often. Have you heard of the IFT Foundation? Also, the Food Packaging Forum?
I’ve seen some other mats that can go to 440 and 450o. Also, the ones I have say 428 and that they CAN go in the dishwasher.
Just pay attention to what is on the packaging and you should be good to go.
Very nice, i love silicone cookware.
Is it then recommend to use with the facts raised ,And how would a buy with know how differencite good bad silicone baking mould’s
One of the best ways to test if silicone is free of impurities and genuinely food-grade is to twist it. If the color stays the same, it’s likely food-grade. If it turns white, it’s likely impure and not suitable for use in cooking or baking.
Good article/report. I have a kitchen full of Corningware, cast iron, stainless cookware, aluminum baking sheets, ceramic and glass baking pans. Thought I was missing something by not having a collection of silicone. Guess I really don’t need the latest fad.
Are there health risks if steaming highly acidic foods on a white silicone steamer?
Silicone is a non-reactive material, so if you’re using genuinely food-grade silicone to steam food there shouldn’t be any issue.
Thank you, Leigh. Medical-grade and food-grade silicone steamers are better than stainless steel steamers in cooking highly acidic foods.
It is interesting how people will donate silicone to thrift store so some uneducated person can take the risk. If you really cared, you would dispose of it, or keep it and use for purposes where leaching is not an issue. They can be used for art projects, etc.
I am surprised you give cast iron 5 leaves. It takes an incredible amount of energy to create, it is not very biodegradable, and while technically recyclable, again requires huge amounts of energy to recycle. Isn’t there anything kinder to the environment than cast iron?