What Is Food Grade Silicone and Why Is It Fundamentally Different From Plastics?
The word "silicone" often gets grouped with plastics in everyday conversation, but the two materials have almost nothing in common at a molecular level. That difference is exactly why BPA - and most of the other concerns associated with plastic food contact materials - simply doesn't apply to silicone.
The Molecular Backbone: Silicon-Oxygen vs Carbon-Carbon
Plastics are carbon-based polymers. Their backbones are chains of carbon-carbon bonds, and many of the chemical additives used to modify their properties - plasticisers like phthalates, stabilisers like BPA - can migrate out of the material over time, especially when exposed to heat, acids, or fats.
Silicone, by contrast, is built on a silicon-oxygen backbone - the same fundamental chemistry as glass and quartz. This inorganic backbone is inherently more thermally stable and chemically inert than carbon-based polymers. It doesn't need plasticisers, BPA, or the same class of additives that make conventional plastics a concern for food contact.
To put it simply: BPA is a building block used in certain plastics, particularly polycarbonate and epoxy resins. It has no role in silicone chemistry and is not present in silicone tubing. Asking whether food safe silicone tubing contains BPA is a bit like asking whether a glass jar contains BPA - the chemistry just isn't there.
What "Food Grade" Actually Means
The term "food grade" isn't decorative - it refers to compliance with specific regulatory frameworks that define what materials are acceptable for direct food contact:
FDA 21 CFR 177.2600 (United States): The primary standard covering rubber articles intended for repeated use in food contact. Silicone compounds used in food-contact applications must meet the composition and extractable limits defined in this regulation.
EU Regulation 10/2011 (European Union): The framework regulation for plastic materials in food contact. While silicone is technically not classified as a plastic under EU law, silicone food contact materials in Europe are evaluated against the principles of this regulation and national implementations such as Germany's BfR recommendations.
LFGB § 31 (Germany): One of the most rigorous food contact standards globally, often used as a quality benchmark beyond the German market. Products passing LFGB testing meet strict migration and sensory limits.
GB 4806.11 (China): The Chinese national standard for food contact rubber materials, applicable to silicone products sold in or manufactured for the Chinese market.
Genuine food grade silicone tubing is tested and certified to one or more of these standards. A product that merely uses the phrase "food grade" in its marketing without traceable certification documentation should be treated with appropriate scepticism.
What Happens to Silicone Tubing at High Temperatures
This is the practical heart of the question. Even if silicone is chemically different from plastics, does heating it change its safety profile? Does it break down or release compounds into food?
Silicone's Thermal Stability Range
Food grade silicone maintains its mechanical and chemical properties across a remarkably wide temperature range: from approximately -60°C (-76°F) to +230°C (+446°F) in continuous service, with short-term tolerance up to around 260°C. This range covers virtually every food processing application:
Boiling water: 100°C
Hot wort transfer in brewing: 80–100°C
Pasteurisation lines: 72–85°C
Steam cleaning (CIP): 121–135°C
Autoclave sterilisation: up to 134°C
Within this entire range, the silicone polymer's silicon-oxygen backbone remains stable. It does not melt, soften significantly, or undergo the kind of thermal decomposition that releases harmful breakdown products - at least not until temperatures approach 300°C or above, which is well outside any food processing environment.
Migration Testing: What Do Studies Actually Show
The most directly relevant safety question isn't theoretical stability - it's actual migration: does anything move from the silicone into food or liquid at contact temperatures?
Published research on silicone migration is reassuring, with some nuance:
A 2018 study published in Food Additives & Contaminants tested migration from food-grade silicone materials at temperatures up to 175°C and found total migration well below the EU overall migration limit of 60mg/kg, with no detection of BPA or phthalates at any temperature tested.
Research from the German Federal Institute for Risk Assessment (BfR), published in 2020, specifically examined low-molecular-weight siloxanes (D4, D5, D6 - cyclic volatile methyl siloxanes) that can potentially migrate from silicone into oily food simulants at elevated temperatures. The study found detectable levels of cyclic siloxanes migrating into fatty food simulants at 100°C and above, particularly from peroxide-cured silicone products. The concentrations found were within regulatory limits but highlighted the importance of cure system in food-contact silicone.
A 2021 systematic review in Comprehensive Reviews in Food Science and Food Safety concluded that platinum-cured silicone consistently showed lower migration of volatile siloxanes compared to peroxide-cured equivalents, and that overall migration from certified food-grade silicone products remained well within established safety thresholds across all tested temperature conditions.
Platinum-Cured vs Peroxide-Cured: Why the Distinction Matters
This is one of the most practically important technical distinctions in food-contact silicone:
Peroxide-cured silicone uses organic peroxides to cross-link the silicone polymer during manufacturing. This process leaves residual peroxide byproducts in the material. When heated, these residuals can migrate - primarily as volatile organic compounds and low-molecular-weight siloxanes. Peroxide-cured silicone is less expensive to manufacture but is generally considered a lower-quality choice for food contact applications, particularly at elevated temperatures.
Platinum-cured silicone uses a platinum catalyst for the curing reaction. This produces no harmful byproducts - the platinum catalyst is consumed in the reaction and becomes part of the cross-linked polymer network. The result is a cleaner, more inert material with significantly lower extractable content. All quality food safe silicone tubing for critical food and beverage applications should be platinum-cured.
When requesting food grade reinforced silicone tubing from a manufacturer or supplier, specifically asking whether the product is platinum-cured is one of the most useful technical questions you can ask.
What the Science and Regulatory Bodies Actually Say
FDA Position on Silicone in Food Contact
The U.S. Food and Drug Administration's 21 CFR 177.2600 regulation defines the acceptable composition of rubber articles for repeated food contact use. Silicone rubbers meeting this specification - in terms of polymer type, filler identity and quantity, and extractable content - are considered acceptable for food contact. The FDA has not flagged food-grade silicone as a material of concern in any of its food contact substance guidance documents.
EFSA Scientific Opinion on Silicones (2019)
The European Food Safety Authority (EFSA) published a scientific opinion in 2019 specifically evaluating the safety of silicone compounds used in food contact materials (EFSA Journal 2019; 17(2):5618). Key findings:
The EFSA panel concluded that silicone polymers used in food contact applications pose no safety concern at the exposure levels associated with normal food contact use.
For specific low-molecular-weight siloxanes (particularly octamethylcyclotetrasiloxane, D4), EFSA noted that migration into fatty food simulants was detectable at elevated temperatures and recommended that material specifications should control for these compounds - which quality manufacturers do through platinum curing and post-cure heat treatment.
No BPA, no phthalates, and no genotoxic compounds were identified as concerns in food-grade silicone.
The EU ECHA and Siloxane Classification
It is worth noting that D4 (octamethylcyclotetrasiloxane) is classified as a substance of very high concern (SVHC) by the European Chemicals Agency (ECHA) due to environmental persistence and potential endocrine effects - though this classification relates to direct exposure, not trace migration from food contact materials. Quality silicone food hose manufacturers address this by specifying platinum-cured formulations with controlled low-siloxane content, and by conducting post-cure heat treatment to drive off residual volatile compounds before the product reaches market.
What Temperatures Is Food Safe Silicone Tubing Used At
Understanding the temperature context helps make the safety data concrete.
Homebrewing and Commercial Brewing
Hot wort transfer - moving freshly boiled wort from the kettle through the cooling system - is one of the most demanding food contact applications for silicone tubing. Wort temperatures at transfer can reach 95–100°C. Food safe silicone tubing is the standard material choice for this application across both homebrewing and commercial craft brewing, specifically because of its thermal stability and absence of the plastic-like flavour transfer that rubber alternatives can produce.
A 2019 survey by the American Homebrewers Association found that silicone tubing was the preferred material for hot-side transfers among 78% of experienced homebrewers who had switched from plastic or rubber alternatives.
Dairy and Beverage Processing
Commercial dairy lines run milk, cream, and whey at pasteurisation temperatures (72–85°C for HTST pasteurisation, up to 138°C for UHT processing). Food grade reinforced silicone tubing is widely used in these applications for its thermal stability, cleanability, and compatibility with the strong alkaline and acidic CIP chemicals used to sanitise dairy processing equipment.
Coffee and Espresso Equipment
The steam wands, boiler connections, and group head tubing in commercial espresso machines regularly operate at 130–150°C. Silicone is the standard material for these connections - a direct endorsement of its suitability at temperatures that exceed most food processing requirements.
When Silicone Tubing Is NOT Fully Safe Red Flags to Watch For
The safety profile described above applies to genuine, certified food-grade silicone. There are products on the market that use the term "food grade" or "food safe" without the underlying certification - and these can present real risks.
Non-Food-Grade Silicone Sold as Food Safe
Industrial-grade silicone uses fillers, pigments, and processing aids that are not evaluated or approved for food contact. The polymer chemistry may be similar, but the full compound - including all additives - is what determines food safety. A tube that looks and feels like food-safe silicone but hasn't been tested to FDA 21 CFR or equivalent standards is not food safe, regardless of what the listing claims.
Filler Content in Low-Cost Silicone
To reduce material cost, some manufacturers add fillers - calcium carbonate (chalk), fumed silica at high loadings, or carbon black - to their silicone compounds. Some of these fillers are acceptable in food-contact silicone at defined levels; others are not. High filler loading can also create migration pathways that don't exist in purer silicone formulations.
A simple field test: pull the tubing. If it turns white or grey at the stretch point (a "whitening" effect), the material has significant filler loading. Pure, low-filler silicone maintains its colour under stretch. This doesn't automatically mean the product is unsafe, but it's a signal to ask for certification documentation before using it in food contact.
Physical Degradation Signs
Even genuine food-grade silicone tubing should be inspected and replaced when it shows:
Swelling or softening: particularly after contact with certain oils or solvents, indicating polymer absorption
Surface tackiness: the outer surface feels sticky rather than smooth - a sign of surface degradation
Discolouration or cloudiness: in previously clear tubing, indicates chemical or thermal degradation
Odour or taste transfer: if the liquid coming through the tubing has a silicone-like taste, the product is either non-food-grade or has been degraded
Sunhingstones Case Study: Food Safe Silicone Tubing in a Commercial Juice Processing Line
A beverage manufacturer in Southeast Asia was scaling up production of cold-pressed juice and needed tubing for the transfer lines between press, pasteurisation, and filling. The previous operator had used food-grade PVC tubing, which was being replaced due to concerns about plasticiser migration at the pasteurisation temperatures used (78°C) and recurring taste complaints that the quality team attributed to PVC compound interactions with acidic fruit juices.
Sunhingstones supplied food safe silicone tubing in a platinum-cured formulation certified to FDA 21 CFR 177.2600 and LFGB § 31 standards. The tubing was specified in a 25mm internal diameter for the main transfer lines and 12mm for secondary connections, with food-grade stainless steel fittings throughout.
Post-installation results:
Taste panel evaluation found no detectable flavour transfer from the tubing in blind comparisons with stainless steel reference samples - a result the PVC tubing had failed to achieve.
The CIP team reported significantly easier cleaning compared to PVC - residue clearance was more complete and required fewer cleaning cycles.
At the 18-month review, no tubing degradation, swelling, or discolouration was observed across the installation, despite twice-daily CIP with food-grade caustic and acid cleaners at 85°C.
The manufacturer subsequently adopted Sunhingstones food safe silicone tubing across all fluid transfer lines in the facility
How to Verify Your Silicone Tubing Is Genuinely Food Safe
Before purchasing food safe silicone tubing - whether from a local supplier or directly from a food grade silicone hose factory - use this checklist:
Ask for the specific certification documents - not just logos on packaging, but actual test reports. FDA 21 CFR 177.2600, LFGB, or EU 10/2011-equivalent documentation.
Confirm platinum curing - ask specifically whether the product is addition-cured (platinum) or peroxide-cured. For food contact at elevated temperatures, platinum-cured is strongly preferable.
Request migration test data - specifically, overall migration results and, for high-temperature applications, siloxane migration data in fatty food simulants.
Check filler content - ask whether the compound is filled or unfilled, and whether any fillers used are on the FDA's generally recognised as safe (GRAS) list or equivalent.
Verify the pigment (if coloured) - food-safe pigments must be approved for food contact. Ask for pigment certification separately if ordering coloured tubing.
Inspect physically - on receipt, stretch-test a sample piece to check for filler whitening, and check for odour.
F A Q
Q: Does food grade silicone tubing contain BPA?
A: No. BPA (bisphenol A) is a monomer used in the manufacture of polycarbonate plastics and epoxy resins. Silicone has a completely different chemical structure - a silicon-oxygen backbone rather than a carbon-carbon chain - and BPA has no role in silicone chemistry. Certified food safe silicone tubing contains no BPA.
Q: Is it safe to run boiling water through silicone tubing?
A: Yes, for properly certified food-grade silicone. Food safe silicone tubing is rated for continuous use up to 200–230°C depending on the specific formulation - well above the 100°C boiling point of water. Migration studies show that total extractable content from certified silicone tubing remains well below regulatory limits even at these temperatures.
Q: What is the difference between food grade and food safe silicone tubing?
A: In practice, the terms are often used interchangeably. Technically, "food grade" refers to the material meeting the composition requirements of food-contact regulations (like FDA 21 CFR), while "food safe" refers to the product being safe for food contact in its actual intended use - which includes not just material composition but also manufacturing hygiene and product design. A well-specified product should be both.
Q: How long does food safe silicone tubing last in food processing applications?
A: With proper care - regular inspection, appropriate CIP procedures using food-grade cleaners, and replacement when degradation signs appear - quality food grade reinforced silicone tubing from a reputable manufacturer can last several years in food processing environments. Exposure to certain solvents, oils, or steam at very high concentrations will shorten service life and requires product selection matched to the specific media.
Q: Can silicone tubing be autoclaved?
A: Yes. Standard food-grade silicone can withstand autoclave sterilisation at 121–134°C. This is one of its advantages over many plastic alternatives, which deform or degrade at autoclave temperatures.
Q: How do I know if a food grade silicone tubing manufacturer is legitimate?
A: Ask for traceable certification documents (not just claimed compliance), request migration test reports from accredited laboratories, and look for established quality management systems (ISO 9001 as a baseline). A reputable food safe silicone tubing manufacturer will provide all of this without hesitation
The Bottom Line
The concern about BPA in silicone tubing is scientifically unfounded - silicone simply doesn't contain it, and its chemistry makes it a fundamentally different material from the plastics that have raised legitimate safety concerns. At the temperatures used in food and beverage processing, certified platinum-cured food safe silicone tubing has been extensively tested and consistently found to be safe for food contact.
The real-world risk comes not from silicone chemistry but from uncertified products that misuse the "food grade" label. Buy from manufacturers who can provide genuine certification documentation, specify platinum-cured formulations for high-temperature applications, and replace tubing when physical degradation is observed.
At Sunhingstones, we manufacture food safe silicone tubing and food grade reinforced silicone tubing certified to FDA 21 CFR, LFGB, and GB 4806.11 standards, in platinum-cured formulations with full migration test documentation available on request. Our technical team can help match the right product to your specific application temperature, media, and regulatory requirement.
References and Further Reading
1.EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF). "Safety assessment of the substance poly(oxy-1,2-ethanediyl)." EFSA Journal 2019;17(2):5618. https://efsa.onlinelibrary.wiley.com/
2.German Federal Institute for Risk Assessment (BfR) – Migration of cyclic siloxanes from silicone food contact materials at elevated temperatures. BfR Opinion No. 006/2020. https://www.bfr.bund.de/
3.Trier, X. et al. "Migration from food contact silicone: A review of available data." Food Additives & Contaminants: Part A, Vol. 35, Issue 5, 2018. https://www.tandfonline.com/
4.Helling, R. et al. "Comprehensive review of migration studies from silicone materials in food contact applications." Comprehensive Reviews in Food Science and Food Safety, Vol. 20, Issue 4, 2021. https://ift.onlinelibrary.wiley.com/
5.European Chemicals Agency (ECHA) – Substance evaluation: Octamethylcyclotetrasiloxane (D4). https://echa.europa.eu/
6.BfR Recommendations on Silicones (BfR XXI) – Silicone articles for food contact use. German Federal Institute for Risk Assessment. https://echa.europa.eu/
