Silicone (or polydimethylsiloxane) is a man-made polymer and the product of Silica and Carbon when heated together at high temperatures. Silicone is a completely synthetic rubber, and a relatively hybrid material as it formed from organic compounds of Hydrogen and Carbon, known as hydrocarbons.
Silicone-based rubber products are characterised by a number of key properties, including;
- High and low heat resistance
- Chemical Resistance
- High Compressibility
- High Elasticity
- Water Repellency
Silicone can be transported from the temperature of a freezer to that of a hot oven without undergoing any structural changes which may affect its performance as a mold.
The number of silicone applications encountered in everyday life is incredible. From aeroplane engines to swimming goggles, silicone seals and coatings are found in just about every corner of consumer life. The impressive chemical, thermal and mechanical properties of silicone makes the material highly durable and so it is little wonder that it has been widely adopted by a range of industries, not least the food industry.
The FDA (Food & Drug Administration) is responsible for regulation of the food and pharmaceutical industries, in order to protect the public from food and drug hazards. Although the FDA is a body of the US government, and its jurisdiction only applies in the United States, its principles and regulations are adopted as a recognisable worldwide standard.
Silicone’s resistance to temperatures and chemicals ultimately means that it does not react with foodstuffs or any other media encountered in the process line. The use of silicone sealing therefore does not result in any hazardous byproducts which could adversely affect the health of the workforce or end consumers. This is important when consider silicone as a ‘food-safe’ material.
However, according to their Food Code, a material is only considered ‘food-safe’ if it is FDA-compliant, which means ‘acceptable to the regulatory authority [FDA] based on a determination of conformity with principles, practices and generally recognized standards that protect public health’. Whilst the characteristics of silicone makes it highly durable and resistant, there is no automatic universal ‘approval’ of all silicone products or manufacturers.
What Is Food Grade Silicone?
Food grade silicone is a type of silicone that is safe for use with foods. The silicone is used frequently in making molds to use for food that begins as liquids and solidify. It is nontoxic; does not stain food, dishes or cookware; is easily removed from cast objects; and is safe for use on various plastic objects.
Uses and Forms
Food grade silicone is often used to make molds of nonfood items for later use as molds to cast food items into the shape of the initial nonfood item. The molds are used for making shapes out of chocolates, butter, gelatin, cheese and candies. Food grade silicone is also used in food processing and packaging to keep foods from coming into contact with unsanitary surfaces while being transported across assembly lines. Hunters and butchers use lubricant food grade silicone to prevent rusting in grinding and cutting machines because it is safe for consumption.
Food grade silicone can be found in various forms to make it more practical for the different uses and jobs it is capable of taking on.
Found in a tube, food grade silicone often resembles cake icing and can be squeezed onto the objects to be molded. It may also be found as a thinner liquid, which will need to be mixed and then poured over the cast objects. Some food grade silicone can be found in a thick consistency much like clay; this type is used for small, typically flat objects that can be pressed into the silicone to create the mold. Another form of food-grade silicone is the aerosol or liquid form used primarily as a lubricant in food packaging and to protect the food from the introduction to toxic or unclean conditions.
Food grade silicone, as an aerosol or liquid, is flammable when exposed to direct flame, so this type should be avoided in applications requiring such exposure. Food grade silicone in clay-like form and those used to make molds are registered for safe use in temperatures up to 450 degrees Fahrenheit. Users should read specific instructions for each type in order to use them properly and without problems.
The amount of time it takes food grade silicone to solidify for use as a mold depends on the type of silicone (poured, squeezed from tube or clay-like) and the brand of silicone. Many will set in just a few hours, while others will take only a few minutes. Some may need to set in room temperature, while others can be placed in the freezer for a quicker setting.
Why choose Silicone over plastic?
- Plastic are made with carcinogenic and endocrine/hormone disrupting chemicals that in certain amounts can cause adverse effects whilst silicone is chemically inert, so non-toxic and will not leach into food or drink.
- Plastic whilst it can last a life time (actually on average 450 years) is prone to damage such as scratches and cracks with items often being disposed of with-in a few years. (We’ve all owned a plastic sandwich/tupperware box, they never lasted very long before the lid cracked or the container became discoloured!) Silicone is a more durable, flexible material being able to withstand extreme temperatures with out degrading.
- Plastic due to scratches on the surface can harbour germs, silicone is hypoallergenic and will not harbour bacteria.