Does Anchor Hocking Use Borosilicate Glass? Exploring the Truth Behind One of America’s Most Beloved Glassware Brands

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Introduction: What Defines Quality in Glassware?

When it comes to kitchen glassware, quality and safety are top priorities for consumers. One of the most iconic names in American glassware, Anchor Hocking, has been a staple in homes across the country for over a century. Known for its durability and affordability, Anchor Hocking is often associated with heat-resistant glass, particularly in items like measuring cups, casserole dishes, and baking ware.

But a recurring question among consumers and kitchen enthusiasts alike is:
Does Anchor Hocking use borosilicate glass?

This article delves deep into the materials Anchor Hocking uses in its products, the evolution of glass technology in kitchenware, and how the company’s offerings compare with those of other major brands in terms of safety and performance.

A Brief History of Anchor Hocking

Before we explore the technical side, let’s look at the legacy behind the brand. Founded in 1905, Anchor Hocking has played a pivotal role in shaping the American household goods industry. It became particularly known for its introduction of canning jars and later expanded into ovenware and kitchen glassware.

By the early to mid-20th century, Anchor Hocking was a leader in producing “fire king” glass, a type of heat-resistant glass designed to withstand high temperatures. This innovation coincided with the introduction of tempered glass and became synonymous with durability and utility in the kitchen.

Borosilicate vs. Soda-Lime Silicate: What’s the Difference?

To answer the core question of this article, it’s essential to understand the different types of glass commonly used in food and bakeware:

Borosilicate Glass – Contains boron trioxide, which allows the glass to withstand thermal shock (rapid temperature changes). Known for its durability, it’s used in laboratory glassware and high-end kitchenware like Pyrex.
Soda-Lime Silicate Glass – Less expensive, more widely used, but more prone to thermal shock. May crack or shatter when exposed to drastic temperature changes.

In addition to these, tempered glass is also used in oven-safe products. Tempered glass undergoes a controlled thermal or chemical treatment that increases its strength compared to regular glass.

Anchor Hocking and Borosilicate Glass: A Timeline

The Early Use of Borosilicate

Historically, many glass bakeware brands, including Pyrex and Anchor Hocking, used borosilicate glass in their products. This was especially important as consumers needed glass that could handle the rigors of baking, refrigeration, and reheating.

However, in the 1980s, Anchor Hocking, much like Corning (the parent company of Pyrex), began to shift from borosilicate to tempered soda-lime silicate glass. This change is attributed to cost considerations, manufacturing ease, and general consumer use patterns that did not demand ultra-high thermal shock resistance in everyday kitchenware.

Why the Change Occurred

The move away from borosilicate glass was not due to any inherent performance issues but rather a strategic business decision. Borosilicate glass is more expensive to produce and requires more precise manufacturing processes. With a growing consumer base expecting affordable and reliable options, soda-lime glass (especially when tempered) offered a more cost-effective alternative.

That said, tempered soda-lime glass still resists thermal shock better than untreated glass and is suitable for most home baking applications unless abrupt, extreme temperature changes are involved (e.g., taking a dish from the freezer to a preheated oven).

What Do Current Anchor Hocking Products Use?

Modern-day Anchor Hocking baking and oven-safe glassware (such as the Glass Classic Mixing and Measuring Bowls or casserole dishes) are typically made from tempered soda-lime silicate glass. This is clearly stated on packaging and in manufacturer guidelines for usage.

While the material is not borosilicate, Anchor Hocking emphasizes that its products are tempered to withstand heat up to certain thresholds, typically up to 425°F (220°C), depending on the item.

Anchor Hocking Product Temperature Guidelines

Source: Anchor Hocking Official Website & Product Packaging

How to Identify if a Product Is Borosilicate or Not

Consumers who are particularly concerned about thermal resistance can use a few key strategies to determine the type of glass used in Anchor Hocking and other brands.

Check Product Labels and Manufacturer Guidelines

Most baking and oven-safe glassware will state if it’s tempered or specify its maximum safe temperature. Borosilicate glass is often clearly labeled, as it is a selling point for durability and heat resistance.

Look for Design Clues

Borosilicate glass is generally more lightweight and has a slight amber or subtle transparency compared to soda-lime silicate’s clearer white appearance. However, this distinction can be subtle, and the best approach is to rely on explicit labeling.

Contact the Manufacturer

Anchor Hocking offers easy access to customer service either via their official website or toll-free number. Inquiries about materials used in specific product lines will typically be answered within 24–48 hours.

Anchor Hocking vs. Pyrex: A Comparison

Since Pyrex and Anchor Hocking are both major players in the oven-safe glassware market, it’s helpful to compare their materials and safety standards.

Material Composition

Source: U.S. Consumer Product Safety Commission reports and manufacturer disclosures

While both brands historically used borosilicate, the modern U.S. products are largely made with tempered soda-lime glass. The current European Pyrex (Verrerie et Silex or VSF) still uses borosilicate, which has sparked debate among U.S. consumers.

Performance and Safety Considerations

Thermal Shock Resistance: Borosilicate glass is superior in withstanding thermal shocks. However, Anchor Hocking’s tempered glass still offers significantly more resistance than non-tempered alternatives.
Durability: Tempered glass is more impact-resistant, reducing the chances of chipping or breaking during normal use.
Microwave and Dishwasher Safety: Both Anchor Hocking and Pyrex confirm that their modern glassware is safe for microwave and dishwasher use, provided guidelines are followed.

Safety First: Best Practices for Using Anchor Hocking Glassware

To maintain the safety and longevity of Anchor Hocking’s glass bowls and dishes, consider the following usage guidelines.

Avoiding Thermal Shock

Thermal shock occurs when glass is exposed to abrupt temperature changes and can lead to cracking. Anchor Hocking recommends:

Do not place cold glassware directly into a hot oven (or vice versa)
Avoid adding liquid to hot glassware
Do not use over direct heat sources like stovetops or open flames

Use Within Temperature Ranges

While Anchor Hocking glassware is oven-safe, always ensure the oven temperature does not exceed 425°F unless otherwise specified. Use oven mitts or gloves to handle the glassware when it’s hot.

Proper Cleaning Practices

Anchor Hocking glassware is dishwasher-safe and is designed for repeated use. However, over time, frequent dishwasher cycles may lead to cloudiness due to mineral buildup. Using a rinse aid and cleaning the glass with vinegar occasionally can help maintain clarity.

Why Does the Borosilicate vs. Tempered Debate Matter?

While some consumers might not notice a dramatic difference in their day-to-day cooking, the type of glass used does have implications — particularly when it comes to:

Product Longevity

Borosilicate glass tends to last longer under varying temperature conditions, making it ideal for serious home chefs or those who frequently make dishes that involve going from fridge to oven (or vice versa).

User Safety

According to reports from the Consumer Product Safety Commission (CPSC), consumer complaints related to sudden shattering of tempered glass have increased over the years. While most instances result from misuse, the glass’s inherent limitations in withstanding thermal shock remain a concern.

Educated Consumer Demand

More consumers are becoming informed about food safety and quality materials. As a result, the use of borosilicate has returned — not across all glassware, but in niche and high-end products. Anchor Hocking may not return to using borosilicate broadly due to cost and market competition factors, but alternative brands are cashing in on the demand.

Other Manufacturers That Use Borosilicate Glass

While Anchor Hocking predominantly uses tempered soda-lime silicate, other companies continue to use borosilicate in select or full product lines:

Brand	Primary Glass Type	Common Products
Visions (CorningWare)	Ceramic glass (borosilicate-based)	Stovetop-safe cookware
Pieper Glass (Germany)	Borosilicate	Baking dishes, oven-safe containers
International Cookware (Chefman)	Borosilicate	Microwave-safe containers, food storage
Pyrex (European Versions)	Borosilicate	Measuring cups, baking dishes

If you’re seeking borosilicate for added safety and durability, these brands may be more aligned with your preferences.

Concluding Thoughts: Is Anchor Hocking Safe?

So, does Anchor Hocking use borosilicate glass? The straightforward answer is no, not in its current U.S. product lines.

Anchor Hocking glassware today primarily uses tempered soda-lime silicate glass, a material that offers good durability and heat resistance for average kitchen use, while remaining more affordable.

While some may miss the benefits of borosilicate, tempered glass remains safe and effective when used according to the manufacturer’s instructions. Anchor Hocking continues to prioritize consumer safety through clear labeling, temperature guidelines, and a commitment to reliable design.

If you’re someone who needs glassware that can endure frequent temperature fluctuations — such as those moving between the freezer, stovetop, and oven with rapid changes — you might consider exploring alternative brands that continue to manufacture borosilicate glass products.

However, for the majority of home cooks who want a trusted, affordable, and oven-safe option that has stood the test of time, Anchor Hocking remains a strong choice.

Key Takeaways

Anchor Hocking currently uses tempered soda-lime silicate glass in most of its American products.
Borosilicate was used historically but was phased out in the 1980s for economic and logistical reasons.
Anchor Hocking products are oven-safe up to 425°F but should not be exposed to abrupt temperature changes.
The use of tempered glass provides sufficient thermal resistance for most home cooks, assuming proper use.
For those desiring borosilicate glass, alternative brands in various global markets offer that option.

Final Verdict

While Anchor Hocking no longer uses borosilicate glass, the brand still delivers quality, heat-resistant products that are safe and widely trusted. As with any glass bakeware, understanding its materials and adhering to usage guidelines is essential for safe, long-term enjoyment in the kitchen.

Whether you’re a longtime Anchor Hocking user or a consumer curious about materials in kitchenware, always prioritize manufacturer instructions and proper care — because safety starts in your hands.

Is Anchor Hocking glass made from borosilicate?

Anchor Hocking, a well-known American manufacturer of glassware, does not typically use borosilicate glass in most of its products. Instead, the company primarily utilizes soda-lime glass, which is a more common and cost-effective material for everyday glassware. Soda-lime glass is known for its clarity and affordability, but it has a higher thermal expansion rate than borosilicate, making it less resistant to thermal shock.

This distinction is important for consumers who are looking for glassware that can withstand extreme temperature changes, such as moving from the freezer to the oven. While Anchor Hocking does produce items designed for food storage and some oven use, they are generally not made from borosilicate glass. Instead, their tempered glass products are heat-treated to enhance durability, though not to the same degree as borosilicate glass.

What is the difference between borosilicate glass and soda-lime glass?

Borosilicate glass contains boron trioxide, which significantly reduces its coefficient of thermal expansion. This makes it highly resistant to thermal shock, meaning it can endure sudden temperature changes without cracking or breaking. It’s commonly used in laboratory glassware, cookware, and high-end drinking glasses. This type of glass is also known for being durable and less likely to discolor or degrade over time.

Soda-lime glass, on the other hand, is made primarily of silica, sodium oxide, and lime. It’s the most common type of glass used in food and beverage containers, as well as window panes and everyday items. While more affordable and easier to produce, it’s less resistant to heat and more prone to breakage under thermal stress. Anchor Hocking uses this type of glass in the majority of its consumer products, focusing on mass production and accessibility.

Why did Anchor Hocking switch from borosilicate to soda-lime glass?

Anchor Hocking, like many other American glass manufacturers, made the transition from borosilicate to soda-lime glass in the late 1990s to early 2000s. The shift was largely driven by economic factors, as soda-lime glass is less expensive to produce and easier to form into molds, which helps reduce manufacturing costs. This allowed the company to maintain competitive pricing while expanding production capabilities.

Additionally, new thermal and chemical tempering methods became available, improving the durability of soda-lime glass products. These advancements enabled Anchor Hocking to produce tempered glassware that could still meet consumer expectations for everyday use, including limited heat resistance. While not as durable as borosilicate, tempered soda-lime glass offered a more cost-effective solution without a significant compromise on performance for routine household applications.

Are there any Anchor Hocking products that contain borosilicate glass?

While Anchor Hocking largely transitioned to using tempered soda-lime glass for most of its product lines, there have been occasional specialty or commercial-grade items that may incorporate borosilicate materials. However, these are not standard across their typical retail offerings and are often reserved for industrial or professional use. Consumers are advised to check labeling or contact the company directly for confirmation on specific products.

Most Anchor Hocking glassware found on store shelves, such as drinking glasses, measuring cups, and food storage containers, are made from tempered soda-lime glass. Even those labeled as “heat-resistant” or “oven-safe” usually rely on tempering processes rather than the inherent properties of borosilicate. Therefore, while borosilicate is present in niche product categories, it is not the standard material used in the brand’s consumer-oriented glassware.

What are the safety implications of using tempered soda-lime glass versus borosilicate glass?

Tempered soda-lime glass undergoes a special heat treatment that makes it significantly stronger than regular glass and able to withstand moderate temperature fluctuations. If broken, tempered glass breaks into small, blunt pieces rather than sharp shards, which reduces the risk of injury. It’s generally safe for food and beverage use and meets industry standards for consumer safety, including FDA guidelines.

However, it still has a lower thermal resistance compared to borosilicate glass, meaning it’s more likely to crack or shatter when exposed to extreme or sudden temperature changes. For example, pouring boiling water into a tempered glass measuring cup can pose a risk. Consumers should always check manufacturer guidelines for safe usage temperatures and avoid abrupt thermal shifts to ensure safety and prolong product life.

How can I tell if my Anchor Hocking glassware is borosilicate or soda-lime?

Unfortunately, older Anchor Hocking glassware may not clearly specify whether it is borosilicate or tempered soda-lime. To determine the type, look for product labeling on the packaging or bottom of the glass that states the material. If the label isn’t available, contacting Anchor Hocking directly with the product model or a photo can often yield a definitive answer.

Another approach is to check the date of manufacture—Anchor Hocking largely stopped using borosilicate glass around the early 2000s. Products appearing after that date are almost certainly tempered soda-lime. If you’re uncertain, contact customer service or consult the Anchor Hocking website for updated product specifications to avoid making assumptions that could lead to breakage or injury.

Is Anchor Hocking glassware safe for microwave and oven use?

Many Anchor Hocking glass products are designed for microwave use and some are also labeled as oven-safe, but these claims generally apply to tempered soda-lime glass varieties. The tempering process allows them to withstand moderate heat, making them suitable for reheating food or baking at low to medium temperatures. However, it is important to follow the manufacturer’s instructions carefully to avoid overheating or sudden temperature changes.

While tempered soda-lime glass can handle heat better than standard glass, it’s not as resilient as borosilicate when it comes to thermal shock. Therefore, it’s best to avoid transferring Anchor Hocking glassware directly from the refrigerator or freezer to the oven. Instead, allow the glassware to reach room temperature before exposing it to heat to prevent potential cracking or breaking.