Types of Glass Bottles — A Thomas Buying Guide
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With a growing focus on reducing plastic packaging, glass bottles are an increasingly attractive alternative for manufacturers. Glass is 100 percent recyclable and can be recycled indefinitely without any reduction in quality. Eighty percent of recovered glass is made into new glass bottles. There are over 80 recycled glass processers across 35 states in the U.S.
Glass is nonporous and impermeable, meaning there is no chemical leaching that would endanger consumers or affect the taste or quality of beverages or food in the bottle. For more extreme bottle contents like alkaline products, different types of glass are used to ensure the integrity of the bottle over time.
Glass bottles are made by mixing materials including sand, soda ash, limestone, and furnace-ready scrap glass, heating the mixture to as high as 1675 degrees Fahrenheit, then formed using a press-and-blow or blow-and-blow process. You can learn more about how glass bottles are made in our in-depth guide on the subject. You can also check out our guide on how plastic bottles are manufactured.
In this guide, we’ll be covering the basic types of glass bottles are made of, as well as some common bottle types used in industrial applications, including:
Food Packers’ Glass Bottles
Pre-cleaned, EPA Level One Glass Bottles
Plastic Coated Glass Bottles
Toiletry & Cosmetic Glass Bottles
Perfume Glass Bottles
Types of Bottle Glass
Most glass bottles are made from one of three different types of glass: soda-lime glass, treated soda-lime glass, or borosilicate glass. In addition to these some decorative bottles are made of leaded or crystal glass. Lead glass includes around 24% lead oxide, while lead-free crystal swaps the lead for zinc oxide, barium oxide, or potassium oxide.
Type III: Soda-Lime or Soda-Lime-Silica Glass Bottles
These are the most common type of glass bottles produced. Type III bottles are most commonly used for food, beverages, and pharmaceuticals, thanks to their relative cheapness, as well as their chemical and water stability. Amber glass bottles are a type of soda-lime glass; they’re tinted to protect sensitive contents like beer or medication from UV light. Made from silica glass with alkali metal oxides, these bottles work best with dry heat sterilization. Autoclaving, the process of sterilization through high-pressure steam, will corrode this type of glass.
Type II: Treated Soda-Lime Glass Bottles
Type II bottles, which are treated with sulfur during the annealing process, are made of the same material as Type III bottles but are less alkali-soluble and more resistant to water. Sometimes these bottles are also treated on the outer surface to strengthen the glass against breakage and reduce friction. These bottles can be used for neutral or acidic products, including injectable medications.
Type I: Borosilicate Glass Bottles
Borosilicate glass bottles are the most durable glass, with 10 times more strength than soda-lime glass. These bottles, often used for chemical lab equipment, are more chemical and temperature resistant than the other two types, with superior water resistance. Thanks to their makeup, which includes large amounts of boric oxide, aluminum oxide, alkali, or alkali earth oxide, type I bottles can be used to store chemicals, products requiring sterilization, unbuffered products, and water and medication meant for injection. Even though this type of glass is resistant to acidic, alkaline, and neutral materials, however, there are still some very high and low pH products that it’s still vulnerable to. Pyrex® branded glass is made of borosilicate.
Types of Bottles
Food Packers’ Glass Bottles
Although glass bottles for food products are heavier than their plastic equivalents and risk breaking if dropped, they have a number of key benefits in terms of health and food safety. Their non-porous and impermeable nature means glass bottles have no chemical contaminants and do not degrade over time like plastic. Outside moisture is less likely to enter a glass bottle reducing the risk of mold, while the absence of chemical interaction means products will retain their aroma and flavor more effectively. Glass bottles are chemically inert, which is important to consumers concerned about ingesting dangerous chemicals such as BPA.
Pre-Cleaned, EPA Level One Glass Bottles
Standards for contaminant-free, Pre-Cleaned EPA Level One Glass Bottles are set out in the U.S. Environmental Protection Authority (EPA)’s Specifications and Guidance for Contaminant-Free Sample Containers. Applications include lab-work, sampling, testing, and validation. Pre-cleaning is important because even brand-new bottles may contain contaminants from manufacturing or handling which will skew results.
Pre-cleaned glass bottles are supplied with caps attached and can be certified by a third-party before delivery. “Pre-cleaning” is a broad term and may refer to cleaning for contaminants, cleaning for particulate contamination, sterilization, or cleaning for visible particles.
Plastic-Coated Glass Bottles
Plastic-coated glass bottles provide protection from mechanical impact (dropped glass) and help reduce leakage of the bottles’ contents when the glass breaks. This is ideal for handling volatile substances as the plastic coating will contain the substance long enough after breaking the glass to arrange safe disposal.
Having plastic coating over glass gives users the chemical resistance of glass and the safety of plastic. The maximum temperature for these bottles is lower than glass-only bottles – plastic-coated glass bottles should not be used above 302 degrees Fahrenheit or over direct heat or flame.
Toiletry and Cosmetic Glass Bottles
Like food-packers’ glass bottles, toiletry and cosmetic glass bottles are popular because their chemical inertness means that the products applied to consumers’ skin do not contain chemicals leached from the packaging. Glass is used to protect the product, prevent deterioration and maintain odor and freshness. As with food packaging, the trend towards waste reduction is making glass an increasingly attractive alternative to plastic.
Perfume Glass Bottles
Perfume glass bottles have been in use since 1000 BC, when the Ancient Egyptians’ main use for glass was for storing perfume. The priority of perfumers is to preserve the scent and ensure as best as possible that it does not change over time through exposure or chemical interaction with its packaging.
Glass is also seen as more up-market and visually appealing than other packaging alternatives, with the look and feel of a perfume bottle being an important part of consumers’ purchasing decisions.
