Glass is often described as one of the most nontoxic options for kitchen cookware and drinkware. But, is it really nontoxic?

Since glass can be created with different formulas (or recipes), how safe glass is as cookware, drinkware, and food containers depends on what it's made of and if it's decorated. The most concerning ingredients that glass has been reported to contain include:

• Lead (neurotoxic)
• Cadmium (neurotoxic)
• nanoparticles (minuscule size pose unknown but concerning risks; e.g., they may enter cells and travel throughout our bodies)

Regardless, since no material for cookware, food storage containers, beverage containers, drinkware, and bakeware is 100% nontoxic and risk-free, glass is generally one of the safest materials to include in your kitchen. But a few details can reduce your toxic exposures from glass.

As a conscious consumer, avoid the key things below when shopping for, auditing, and editing your glass products.

In this article, we explore glass as a material in your practical nontoxic kitchen. Below, you will learn more about glass as bakeware, drinkware, food storage containers, and cookware as well as the #1 type of glass to look for.

Two common types of glass

When shopping for glass kitchen and bar products, be aware of two types of glass that are often used: borosilicate glass and soda-lime glass.

Borosilicate glass containers are more heat resistant than other forms of glass so they can be used in the freezer, microwave, and oven. The two key chemicals in borosilicate glass are boron trioxide and silica, which are reportedly safe and environmentally-friendly.

Less expensive and readily available, soda-lime glass is relatively durable at only normal temperatures. It’s susceptible to shock and does not handle extreme changes in heat.

Avoid lead in glass

Beware that crystal, lead-crystal, glazes, colors, or other decorative elements on glass may contain heavy metals or toxic/risky chemicals. Possible indications that glass contains lead:

• Sound. Tap the glass gently with a knife. A drawn-out chiming sound can indicate lead crystal. A duller, briefer sound (like a thud) when struck is generally created by regular glass.
• Weight. Glass with lead tends to be heavier.
• Markings. Examine your glass product for any manufacturer markings and research them. This can sometimes reveal whether there is lead in the glass.
• Prisms. Check online for articles on what to look for when examining how light reacts to the glass. 

Glass ingredients in our diets

What touches our food and drinks can contaminate what they contain. So use glass thoughtfully.

Glass is a time-tested material and can be nontoxic. It is an essential material in my practical nontoxic approach.

Below are the various ways that glass is used in my home. I buy them in borosilicate glass when possible.

Bakeware

Glass bakeware can be used to bake bread and pies. I grease their inner surface areas with butter for nonstick properties before pouring in a recipe for bread or pie crust. 

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I have successfully made bread and pie crust in glass bakeware. Be aware that some Internet articles report that baking pie in glass can lead to uneven heating.

Drinkware

Borosilicate glass is one of your best options. Soda-lime glass is a practical nontoxic option too. Just beware that soda-lime glass may break more easily but is also less expensive.

Again, beware that decorative glass—glass with glazes or enamel, is colored, and lead crystal (or crystal)—may leach toxic chemicals. So research your purchase of glass drinkware carefully.

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Food containers

I love glass food containers that are multipurpose because they are safe enough to be used in the oven, microwave, and freezer. This type of versatile glass is made of borosilicate glass. Borosilicate glasses are more resistant to thermal shock than any other common glass.

Another popular glass product I use for food and beverage containers are mason jars. These have been so versatile in my kitchen! We use them for storing homemade sauces and dips, soups, dehydrated fruit, nuts, and more. Be aware, however, that the lids are reported to contain BPA, an endocrine disruptor.

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Lids

I try to buy lids that are made of medical-grade silicone but that is increasingly hard to find. Most often, they are made of plastic and it's hard to learn which type of plastic. 

So avoid having your food stay in contact with the lid; i.e., don't fill your mason jar to the rim so that it avoids constant contact with the lid since most lids may leach toxic/risky chemicals.

Pyrex

Established as a safe household glass, Pyrex was originally made of borosilicate glass when it was launched in 1915. However, its formula has changed and some Pyrex products are now made of soda-lime. There are also online reports of lead being detected in some. So, when purchasing Pyrex, please keep this in mind and read the manufacturer's claims carefully. Ask the manufacturer any questions you have before deciding on your purchase.

 

 

 

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Conclusion

While formulas for glass vary, glass is an essential material in my practical nontoxic kitchen. My preferences are borosilicate glass with no decorative or colored elements. Soda-lime glass can be a fine option. But beware of decorative elements, colors, and lead glass.

Select sources

Garbo Glassware. "How to know whether the glass cups and bottles contain lead or not." Pulished on Feb. 15, 2019. https://www.garboglass.com/news/whether-the-glass-cups-and-bottles-contain-lead-or-not.html

University of Plymouth. "Drinking glasses can contain potentially harmful levels of lead and cadmium." ScienceDaily. ScienceDaily, 6 November 2017. <www.sciencedaily.com/releases/2017/11/171106100513.htm>.

Webb, Irina. Updated: December 30, 2019. "Lead Free Glassware Brands." https://ireadlabelsforyou.com/lead-free-glassware-options/