Have you tried to remove lingering smells from plastics or silicone to no avail?
My favorite fermentation weight is made from silicone. It works like a charm for keeping fermenting sauerkraut, pastes, relishes and brine-fermented vegetables below the brine. However, it retains odors. Locks onto them with steel fists. Just like the silicone sealing ring in my Instant Pot that I gifted myself for Christmas last year.
I searched long and hard and tested various methods to figure out how best to remove odors created by strong smelling foods – onions, garlic, tomatoes, and… sauerkraut! – from silicone or plastic. In the process, I unearthed two essential keys to finding methods that work.
My Criteria for Removing Odors from Plastic and Silicone
A bit of research resulted in two different solutions. Since plastic and silicone are made from different materials, they require separate methods for removing their odors. But, whatever the method, I wanted to feel comfortable using it.
- No nasty chemicals. I keep a pretty “green” home, so I’m not about to buy some harsh chemical to clean my fermentation weights or lids.
- No harsh abrasives. Abrasives can damage both silicone and plastic, releasing their manufacturing chemicals or removing non-stick properties.
- No high heat. With silicone, using too of a high leaches out chemicals. With plastic, high heat sets odors.
Odors with Silicone
Silicone is used in a variety of fermentation tools. One of my favorite fermentation weights, the Pickle Pusher, reviewed here, is made from silicone. Many fermentation lids use a silicone gasket for a leak-proof seal. MasonTop's Pickle Pipe, reviewed here, and their many copy-cats are made from silicone. And, to keep small bits from floating to the surface during fermentation, some use a silicone mat as a Floaties Trap.
The problem with using silicone for fermentation is that it retains odors due to the properties of the molecules used to make silicone.
Properties of Silicone
Silicone is a synthetic polymer made up of silicon, oxygen and other elements, most typically carbon and hydrogen. It has a rubber-like consistency that is nonstick and resists heat.
When heated, the molecules in the silicone expand, absorbing oils and odors. When the silicone then cools down, the odors get trapped. Even though no heat is used during fermentation, somehow the odors still get trapped in the molecules. Maybe our team of bacteria generates heat as they work. 🙂
ESSENTIAL TIP #1: The application of heat is key for releasing odors from silicone. In this Food52 thread, one contributor shared the following:
“Silicone molecules expand when warm and secrete soaked-in oils and odors.”
Another reader in the thread shared his experience with using heat to remove odors from silicone:
Today I made toasted sriracha sunflower seeds and my Silpat mat was totally sriracha-fied. As mentioned in this thread, I heated my Silpat in the oven, then soaked it in hot water and white vinegar – BINGO!!!! The smell is totally gone. Thank you so much for posting this solution – it was a huge help.
Sounds too simple to be true.
Heating Silicone
Since the only way to remove odors from silicone is to heat it, I wanted to know if there were any dangers from heating silicone.
Silicone is supposedly inert, or chemically stable, meaning that the chemicals used to make the silicone do not leach out, especially when heated. However, that testing was done on medical-grade silicone without fillers or additives and “at body or room temperature.” These studies have shown that silicone is safe at room temperatures and long-term follow-up data support this.
However, I recalled from the research for my blog post, Can I Use Plastic? Silicone? Stainless Steel? for Fermentation, that heating silicone to “high” temperatures, as in bakeware, causes leaching of chemicals.
How high is “high?”
A French study referenced in this blog post on The Eco Mom shows that “these materials are stable up to 300°F (150°C).”
I played around with temperatures and methods and came up with the following solution.
Best Way to Get the Odors Out of Silicone?
First, make sure your silicone item is 100% silicone. Check with the manufacturer, or use the “Twist” Test.
The “twist” test is an easy way to assess the quality of a silicone cookware item. All you have to do is take a silicone product in your hands and twist it. If lots of white streaks appear, it indicates the presence of a large amount of fillers. Pure silicone (safer) will hold its color when twisted. – Belgoods Bakeware
Note: Some of you have asked me about a white powdery sheen developing on your waterless airlock lids. I wonder if some of the inexpensive knockoffs for the MasonTops Pickle Pipes are not using 100% food-grade silicone in their product. When purchasing silicone items, be sure to look for “100% FDA approved food-grade silicone” in the product description.
BONUS TIP: To lift off oils or residue, use a soft sponge or cloth when washing your silicone items. Don’t use the rough side of the sponge or a plastic scrubby. Doing so, just moves the oils around.
Directions for Odor Removal from Silicone
- Preheat the over to 250°F (120°C).
- As the oven is heating, use a gentle dish soap – and a soft sponge or cloth – to wash your silicone item to remove any oils or food residue.
- Place your silicone item on a cookie sheet and put it in the oven to bake out the odors.
- Set a timer for 20 minutes.
- When the timer goes off, give your silicone item the “whiff” test. Pull your silicone item out of the oven and smell it, being careful not to burn your nose. If there is any lingering smell, return it to the oven for 10 minutes. Repeat until no odors remain. It should take no longer than one hour.
- Let cool and give it a final wash.
I used this method to remove the spaghetti sauce smell from the silicone gasket for my Instant Pot and the fermented garlic smell from my Pickle Pusher.
Odors with Plastic
Plastic is used in many of the fermentation lids on the market and in the Canning Buddies fermentation weight.
The problem with using plastic for fermentation is that odors are very difficult to remove.
Properties of Plastic
Plastic is made from hydrocarbons derived from petroleum or natural gas. The hydrocarbons are formed into chains called polymers or plastic resins. By combining hydrocarbon molecules in different ways, different grades of plastics can be created.
Normally, with just a bit of soap and water, you can wipe down the plastic and odors are removed. But, if smelly residues have permeated too long, plastic can develop a long-lasting pervasive odor. In addition, heat can set odors.
Chemistry Lesson: Acids, Bases, and Solvents
Disclaimer. Chemistry is *not* my strong suit. Professor Google helped me on this one along with Tim from Melbourne, Australia who shared his wisdom in this thread.
What happens when you mix vinegar and baking soda? Yes, it bubbles. That bubbling is a chemical reaction. An acid and a base reacting and forming what chemist call ‘salts.’ Salts that grab odors impregnated in the plastic.
Essential Tip #2: Odors must be neutralized before they can be removed.
If your smell is from a food that is slightly acidic, a base will help remove the odor. Fermented foods are acidic, so you would use a base to neutralize it.
BONUS TIP: To lift off oils or residue, use a soft sponge or cloth when washing your plastic items. Don’t use the rough side of the sponge or a plastic scrubby. Doing so, just moves the oils around.
Directions for Odor Removal from Plastics
- Neutralize smell with a base. Sprinkle with a nice layer of baking soda – a base – to neutralize the odor. Gently massage baking soda into the plastic with wet hands.
Bleach and dishwashing machine detergent are also bases but not materials I want to use on my plastics. (White vinegar, tomato juice, and lemon juice are acids and will not create that chemical reaction we are looking for since lingering smells created by fermentation are acids.) - Leave sit for a few hours. From a chemistry standpoint, I don’t know if time helps or not but I felt it did.
- Wash “salts” away with a solvent. Rinse off baking soda then use dish soap – a solvent – and a soft sponge or cloth to remove the “salts” that formed from the reaction you created. Dish soap breaks apart food molecules that are stuck to a dish and then the water removes the stuff.
Distilled water and alcohol are also solvents. - If odors still linger, repeat steps 1-3, or try Step 5 and/or Step 6.
- Let sit in an odor-absorbing material for up to 3 days. If there are lingering odors, place the item in an odor-absorbing material to trap remaining odors. A natural (clay) based or non-toxic cat litter, activated charcoal, coffee grounds, and crumpled newspaper are all possibilities. One of my readers had great success with a bucket of garden dirt. Maybe the bacteria “eat” the odors. 🙂
- “Apply” UV Light and let Ventilate. Placing your plastic item outside within direct sunlight will do much to remove odor. The ultraviolet rays, fresh air, and open space will all work to neutralize the odor and lift it away. Place the item outside on a sunny day until odor is gone.
Other Ways to Neutralize an Acid Smell on Plastic with a Base
- Bleach. Soak item in a mix of 1 part bleach and 5 parts water. Let soak for about an hour. Wash well with soapy water.
- Baking Soda. Soak item in cool water with 1 tsp of baking soda. Let sit overnight
- Dishwashing Machine Detergent. If the item is dishwasher safe, wash in the dishwasher.
Other Solutions?
Is all this work to remove odors in plastic or silicone fermentation weights and lids more trouble than it’s worth? A good question that I will leave for you to answer.
In my blog post, Can I Use Plastic? Silicone? Stainless Steel? for Fermentation I cover all the pros and cons of each material.
Perhaps, an easier solution is to use only glass and stainless steel for fermentation.
Glass Fermentation Items
Here are some currently available glass fermentation weights. I just show the ones with handles since they are so much easier to remove from your jar. 🙂
Stainless Steel Fermentation Items
Here are some currently available stainless steel fermentation kits. You can’t get a seal on your jar without the use of some type of rubber or silicone. Silicone is used where noted.
What have you tried?
What works for you?
What does not work?
Together, we can banish these pervasive odors from our homes. Or… just use glass or stainless steel. 🙂
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Last update on 2019-03-20 / Affiliate links / Images from Amazon Product Advertising API