Will Molds Release BPA or Chemicals When Heated?

Over 90% of plastic food packaging tested in a recent U.S. study leached chemicals under heat. That stat alone is enough to make anyone second-guess the safety of candy or gummy molds, especially when they're used with high-temperature mixtures like sugar syrup or gelatin. 

Quickly put, most molds release chemicals at high temperatures. However, it depends on the material used, the temperature involved, and how the mold was manufactured. 

Here’s what you’ll learn next: which molds can safely handle heat, which ones may pose a risk, and how to choose the right materials when making gummies, chocolate, or hard candy at home.

Part 1- Do Molds Release Harmful Chemicals When Exposed to Heat?

Yes. Heat can cause some molds, especially those made from low‑quality or unregulated materials, to release compounds that migrate into food. 

Which Molds Release Chemicals?

Mostly, plastic molds or low-silicon molds release harmful chemicals on exposure to heat. Here is the reasoning and explanation of this logic:

1- Plastic Molds

Here is a detailed look at why plastic molds could be harmful and how to use them safely:

Why It’s Harmful: Many plastics soften, warp, or degrade at high temperatures. When the material structure breaks down, harmful chemicals are released and migrate into food.

Migrating Chemicals: In addition to bisphenols, migrating chemicals can include various plasticizers and fillers that leach under heat or prolonged use.

• Bisphenols: BPA plus analogues (BPS, BPF) are often used in polycarbonate.
• Plasticizers & fillers: Phthalates or unlisted additives used to make cheaper plastics pliable.

Warning Signs: Recognizing early warning signs can help you avoid exposure to harmful chemicals released by low-quality or unsafe molds.

• Noticeable chemical or “plastic” smell when heated.
• Sticky or oily residue on the mold surface after use.
• Warping, discoloration, surface cracks or crazing.

How to Use It Safely: To reduce the risk of chemical exposure, here are some practical tips for using molds safely during heating and food preparation.

• Only use molds rated for your recipe’s top temperature (e.g., PE/PP ≤ 180°F, PC ≤ 260°F).
• Choose FDA (21 CFR 177.1520/177.1640) or EU‑LFGB certified food‑contact plastics.
• Discard any mold that shows scratches, persistent odors, or visible damage.

2- Silicone Molds

Enlisted below are the reasons that make the silicone molds harmful:

Why It’s Harmful: Low‑cost or filler‑based silicone can contain impurities that break down under heat. These volatile compounds may vaporize and transfer into baked goods or candy.

Curious about the benefits of high-quality silicone? Learn why silicone is considered a safe and practical molding material when used correctly.

Migrating Chemicals: Beyond well-known compounds like BPA, other chemicals in molds can migrate into food, especially when exposed to heat or long-term use.

• Cyclic siloxanes: D4 and D5 may vaporize at high temperatures.
• Residual catalysts or fillers: Uncured residues in budget molds can migrate when heated.

Warning Signs: Even silicone molds can show signs of poor quality; watch for these indicators that may suggest chemical leaching or heat instability.

• Strong rubbery or chemical odor during baking.
• A sticky or oily feel on the silicone after use.
• Shrinkage, brittleness, or color change at normal baking temps.

How to Use It Safely: To ensure your silicone molds remain safe during use, follow these guidelines for heat exposure, cleaning, and storage.

• Select 100% platinum‑cured, filler‑free silicone rated to at least 500°F (260 °C).
• Look for FDA 21 CFR 177.2600 or LFGB certification marks.
• Hand‑wash gently with mild soap; avoid metal utensils that scratch.
• Replace molds yearly or at the first sign of odor, stickiness or physical wear.

For more baking tips, explore our complete guide on baking safely with silicone molds in high-heat recipes.

To extend the life of your molds, here’s a step-by-step on how to properly clean and care for your silicone molds.

Part 2- Safe Molds that Withstand Heat Without Leaching

When selecting molds for high-heat uses like baking or candy-making, it's important to choose materials that remain stable without releasing chemicals. Here are the safest options used by both home cooks and professionals:

1- Platinum-Cured Silicone

This type of silicone is heat-resistant up to 450°F (230°C) and doesn’t release siloxanes when properly manufactured. It’s ideal for baking, gummies, or pouring hot syrups and can handle repeated use without degrading.

2- Stainless Steel or Anodized Metal

These are the most stable mold options for oven or stovetop use. They don’t leach, deform, or react to acidic or hot ingredients, making them a top choice for professional baking setups.

3- Food-Grade Polycarbonate

Commonly used in chocolate molds, polycarbonate can handle up to 260°F (125°C). While safe for shaping tempered chocolate, it’s not suitable for baking or hot sugar work due to the risk of BPA release if overheated.

Want to use polycarbonate correctly? Here's a guide to chocolate molds and how polycarbonate fits in.

Part 3- Chemical Leaching Comparison of Silicone vs Plastic vs Polycarbonate

Not all mold materials react the same way under heat. While some remain chemically stable, others may break down or release compounds into food, especially when exposed to high temperatures repeatedly.

To help you compare their safety and performance, here’s a breakdown of how the most common mold materials behave under heat:

1- Silicone Molds: Watch for Filler-Based Products

High-quality silicone (like platinum-cured silicone) is generally stable up to 450°F (232°C). However, filler-based silicone molds, which are often cheaper and softer, can release siloxanes when heated. These are volatile compounds that may migrate into food under repeated exposure.

Clues that your silicone mold may contain fillers:

• Strong chemical odor when heated
• Turns white when twisted
• Becomes greasy or sticky over time

2- Plastic Molds: BPA and Other Additives May Migrate

Most concerns around plastic focus on BPA (bisphenol A), a compound found in polycarbonate and other rigid plastics. When plastic molds are heated, especially above 120°F (49°C), they can begin to release BPA or similar additives like BPS or phthalates. Even "BPA-free" plastics may still leach unknown substitutes with similar chemical structures,  a risk that increases with repeated heating, scratches, or dishwasher use.

3- Polycarbonate Molds: Stable but Limited by Temperature

Polycarbonate is a rigid plastic commonly used in chocolate molds. It’s generally safe up to 260°F (125°C), but not beyond. Heating it past its limit or using it with hot sugar or oven baking may cause BPA release, especially as the mold ages or cracks. It’s best reserved for low-temperature applications only.

If you’re working with chocolate molds specifically, here’s a step-by-step guide on how to use chocolate molds safely with the right temperatures and techniques.

Part 4- How to Tell If a Mold Is BPA-Free and Food-Grade Certified?

The terms “food-safe” and “BPA-free” are often printed on product listings, but they don’t always guarantee that a mold is actually safe when exposed to heat. 

Here's how to check if a mold is genuinely safe for repeated use with hot ingredients.

1- Look for Reliable Certifications

Certifications are more than marketing; they reflect independent safety testing. Trust only those that are verifiable:

• FDA-Approved (USA): Indicates the material is safe for contact with food, but does not always mean it’s heat-safe unless specified. Look for temperature ratings along with FDA approval.
• LFGB-Certified (Germany): A stricter European standard that tests for chemical migration under heat. Although the FDA doesn’t adhere to this standard, molds with LFGB certification are mostly considered safe to use for baking. 

And if you’re using molds for gummies, make sure you also know how to bloom gelatin properly when making gummies at home to get that perfect texture.

2- Check for Physical Signs of Unsafe or Filler-Based Silicone

Quick in-hand tests can reveal a lot, especially for silicone molds:

• Bend Test (Color Change): If the silicone turns white when you flex or twist it, it likely contains fillers, which are weaker and may break down when heated.
• Smell Test: A strong plastic or chemical odor, especially when the mold is new or exposed to heat, suggests off-gassing, a red flag for unsafe materials.
• Feel & Density: High-quality silicone is thick, flexible, and returns to shape cleanly. Filler-based molds often feel floppy, oily, or uneven in texture.

Conclusion

Some molds can release harmful chemicals when exposed to heat, especially those made from low-grade plastic or filler-based silicone. However, molds made from platinum-cured silicone, stainless steel, or properly rated food-grade polycarbonate are safe when used within their temperature limits. 

The key is knowing what to look for: proper certifications like FDA or LFGB, no chemical smell, no discoloration, and a clearly stated heat tolerance. Many unsafe molds are sold online with vague claims and no testing behind them. With the right materials, you can use heated molds confidently and safely in your kitchen.

Frequently Asked Questions

Can heating plastic molds release toxic chemicals into food?

Yes. Plastics like polycarbonate can release BPA or similar compounds when exposed to high temperatures. Even “BPA-free” plastics may contain unregulated substitutes like BPS, which can also migrate into food under heat. 

Are all silicone molds safe for baking and candy-making?

No. Only high-quality, platinum-cured silicone is stable at high temperatures and resistant to chemical leaching. Low-cost or filler-based silicone molds may degrade or release siloxanes when heated. 

How can I tell if a mold will leach chemicals when used with heat?

You can tell if a mold will release chemicals via warning signs like a strong chemical smell when heated, turning white when flexed, or becoming sticky over time. Lack of certifications or missing temperature ratings is also a red flag. 

Which mold materials are safest for repeated heating?

Platinum-cured silicone, stainless steel, and certified food-grade polycarbonate are considered safe when used as intended. These materials resist degradation and don’t release chemicals under normal baking or candy-making temperatures. 

Why do some molds smell or change color after heating?

That’s often a sign of poor material quality or chemical breakdown. A mold that smells burnt or plasticky, discolors, or feels greasy after use is likely leaching compounds when exposed to heat.