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FAQs About Glass Bottles and Glass Jars

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Have you ever looked at something and started to wonder how it came to be? Curiosity is human nature, and the hunger to find out things about the everyday objects that we use in life is normal. From the moment they are manufactured to the point where they endup in our houses.

The shape and color of a glass bottle are bound to raise serious questions in the mind of the user. These questions are usually structured as Frequently Asked Questions. Most manufacturers have the common ones that pertain to their products, specifically on their websites.

Glass Beer Bottles
Source: Pixabay

Then there are the general questions that no one ever seems to answer. We have compiled a series of answers to some of the FAQs related to glass containers, FAQs that are probably running on your mind right now. The following are some FAQs on glass bottles and glass jars.

Table of Contents

FAQs About Glass Bottles

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Source:Pixabay

Are all types of glass bottles recyclable?

Yes. All types of glass bottles are 100% recyclable. Glass is made from naturally occurring materials like sands and other minerals through various processes. Once glass is made, it takes a very long time for it to decompose. It takes over a million years for glass to completely decompose, what this means is that the first-ever glass to be made is still around, intact.

Due to this reason, the best way to deal with an object possessing such longevity is recycling. All types of glass bottles can be recycled for reuse, and the process spares the environment a lot. For every ton of glass that is recycled, there is a corresponding ton of natural resources that are spared in return.

Why do bottles and jars have thick glass bottoms?

The extra thick bottom in glass bottles is mainly for aesthetic purposes; it gives the bottle a more valuable look. The effect is achieved through the creation of a unique mold called the parison that has a higher glass mass than the other parts of the bottle. This high mass makes the parison maintain that thickness during the blowing process.

Why can't a glass jar and bottle be filled to the brim?

The headspace left at the brim is to allow for the expansion of the liquid inside the bottle as the temperature changes over time. There is a filling method for every liquid in relation to the headspace. Alcoholic drinks, for example, require a headspace of about 4-5% of the total volume of the contents, while something like maple syrup requires a 7% headspace.

What are the small dots on the bottom of a bottle for?

The dots at the bottom of most glass bottles are spaced out in a sequence that represents the mold code number. Their purpose is to allow for an easy electronic process of manufacture during production.

Why is dark glass used for red wine?

The practice of using dark bottles for red wine has a lot to do with tradition; it has been a practice for a very long time. At the same time, it has a lot to do with protecting the contents from the effects of direct sunlight, which can affect the taste and the aging process.

What are the advantages of glass bottles and jars over plastic?

Glass is more environmentally friendly compared to plastic. The number of times you can recycle the same glass bottle is endless. When it comes to plastics, the cost of manufacturing is way lower than recycling. This is the reason why plastics are produced in larger quantities than any other thing.

Are glass bottles biodegradable?

No. Glass is made out of natural minerals like sand. It may break down over time into smaller fragments and turn back into sand, but it is not biodegradable. Once glass is made, it becomes “immortal.”

Why are most beer bottles brown?

In the early days of bottled beer, it used to be packaged in clear glass. With time, however, after being exposed to sunlight, the taste of the beer would be found to be “skunky. The reason for this was the UV light rays that would alter the flavor. This made the bottles to be switched to brown and green.

Is there a special process of making beer bottles?

Beer bottles are made in similar fashion like the rest of their counterparts; the only variation in their manufacture is that they are subject to a higher amount of pressure. Beer bottles must register a pressure resistance of about 6 bars. That is the reason why most of them are thicker.

Why do bottles have the same capacity but different glass weights?

This is all down to their manufacturing process and the brand preferences. For most, the shape of the bottle may need more glass quantities for things like the edges; for others, they may require a more robust mechanical strength; this is the case for carbonated drinks and champagne. In the marketing sense, the heavier a bottle is, the more valuable it looks.

Why does a white film sometimes appear on glasses and bottles?

Humidity is the reason behind this white film. It draws out alkalis from the surface of the glass at a constant rate until all the moisture content is evaporated completely. The cloudy appearance you see on glass is because of the presence of carbonates that form on the surface due to Carbon Dioxide in the air. It is the reason why the glass appears misty the moment you pour a liquid inside.

How is glass color changed?

Glass color can be altered in several ways. The first one is through the addition of colorants. Many bottle manufacturers tend to avoid this route since it forces them to clean the whole furnace to get rid of the coloration that could affect production later on.

Another way of making colored bottles is through the feeders where color flakes are fed into one section of the production creating colored bottles. This is a much more efficient process since it does not require the whole furnace to be cleaned.

Is there any particular difference between blue glass and green glass?

There is not much difference in terms of composition and function when it comes to blue and green glass. The colorants used are what differs between the two. Chromite is used for blue glass and cobalt for green glass. In terms of functionalities, UV filtration is higher in green glass compared to blue glass.

FAQs About Glass Bottles

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Source:Pixabay

Why are glass jars vacuum sealed?

Glass jars are vacuum sealed to extend the shelf-life of the contents inside. There are three methods of vacuum sealing; Dry vacuum sealing, Steam vacuum sealing, and Venting vacuum sealing. Other traditional methods are used in homes across different cultures that have the same effects on the contents.

At what temperature does glass break?

The average temperatures that glass jars are exposed to in our daily lives are too low to affect anything. However, extreme cold temperatures can cause the glass to crack if the contents inside expand. At very high temperatures of about 500°C, it can either crack or change its shape into a plastic-like state.

Is there any difference in composition between cosmetic glass and glass for food products?

The difference is in the materials used. For cosmetic jars, more attention is paid on the appearance. There are specific raw materials used that enhance their “shine.” Some of these materials include barium and nickel alloy that give the containers a gleaming luster and glossy finish. Food products glass does not require any special additions, Being clear enough to see what is inside is all that is needed.

Is it necessary to sterilize jars before canning?

There is no need to sterilize jars before canning. They only need to be clean. Once they are filled with food they are subjected to boiling water baths for about 10 minutes to kill off any potential bacteria that may have been trapped inside the food jar before sealing.

What does “shatterproof glass” mean if the glass still breaks on impact?

The term “Shatterproof” often has its meaning misconstrued. The term simply refers to glass that has undergone a process called “tempering.” The process brings the glass to a temperature of about 600°C before being cooled suddenly. This creates a certain tension within the glass, which causes the glass to break into many tiny pieces on impact. Shatterproof does not in any way refer to glass being unbreakable.

Is it safe to reuse glass food jars?

Yes. Glass jars used for storing food are safe for reuse and can be repurposed indefinitely. The only thing you will need to do is to clean them thoroughly between uses. Another thing you need to be careful about are the lids. Lids once opened cannot be used to preserve canned food again, but can be used to cover jars storing other dry foods.

How many times can glass jars be recycled?

Glass products like jars can be recycled indefinitely without losing a single ounce of the original container. The original minerals used to make the jar in the first place are not altered in any way; the process of melting and recasting is simply repeated over and over again. The shape may change, but the composition does not.

Why does hot water cause glass jars to break?

Strictly speaking, it is not the hot water that breaks the glass, but rather, it is the sudden change in temperature that causes internal stress to be applied on the material. The sudden rise and fluctuation of temperature will break the glass immediately since glass is a terrible conductor of heat. However, if the rise in temperature is gradual, then the glass gets time to adjust slowly and will not break in the end.

Why are glass jars the most hygienic packaging and storage material?

The reason why glass jars are preferred for the storage of most food and drinks is that glass is a neutral object. It does not react in any way when it comes into contact with other things. This makes it the perfect container as it does not alter the taste or the odor of whatever is stored inside it.

Do I need to leave headspace when storing food in a glass jar?

Headspace is important when it comes to storing food in glass jars. If it is canned food, the headspace is vital for a vacuum seal once air has been pushed out and the lid fastened on top. The headspace has to be just right, too much of it and the layer of food at the top will discolor. Too little of it and the lid will not seal properly.

What is Type III Glass?

Glass used for making containers is classified into three distinct groups: Type I, Type II, and Type III. The classification is based on the eventual use of the container since there are specific contents that each type of glass is used for.

Type I glass is also called borosilicate glass, a neutral glass that has high hydrolytic stability making it perfect for storing injectable products like drugs.

Type II glass is derived from Type I through a process that uses a special treatment made of ammonium sulfate. The treatment is applied to the surface of the glass to increase its hydrolytic stability. Type II glass is used to store acids.

Type III glass is made out of soda-lime with very low alkali content. This gives it the highest hydrolytic stability suitable for storing sensitive liquids and solutions like alkalines.

The type of glass that is used for most food storage is called Type A glass and is made using soda-lime but with low hydrolytic stability.

The Bottom Line

Glass bottles and jars are part of our daily lives. They are used to store most of the food and drinks that we consume daily, therefore, having questions and concerns about how they come to be is expected. There are countless questions in regards to glass containers, more than we can cover in this section. The ones we have been able to complete include the most common issues that people may have encountered.

Perfect elaboration

Jasbir Dhaliwal says:
Your comment is awaiting moderation. This is a preview, your comment will be visible after it has been approved.

we got this interest in buying a continuous quantity of glass bottles for alcohol products.

The interest is for:

Item 1
200 ml Flask bottle for screw caps (alluminium)

Item 2
950 or 1000 ml Cristal Bottle optional plastic/cork cap or alluminium screw cap (machine)

Please find some pictures attached.

There would be also some possibilities on 600ml beer bottles (dark colour: amber, green, brown, black)

The volume of interest is about 1 fcl 20′ each item approximately each 3 months (90 days). If possible to mix up the container with these items, it will be better.

Quality: light cristal, cheap product

Shipment: prompt

Payment: 30% advanced and balance against B/L or L/C through first level bank in Uruguay

In case of possibility to offer, please quote:

1. In USDOL (American dollar) per unit, indicating logistics, shipment type (bulk or pallets), quantities per container
2. Please include if it would be possible to include an agent’s commission in case customer decides to import directly
3. Delivery port: Montevideo, Uruguay, final destination the same country

We await your news. Thanks in advance and

Best regards,

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