Creating glass containers can be accomplished by one of two different processes – the Blow and Blow, or the Press and Blow process. Each process is chosen based on the kind of glass bottle being made. All glass bottles start out as raw materials. Silica (sand), soda ash, limestone, and cullet (furnace-ready, recycled glass) are combined into a specific mixture based on the desired properties of the bottle. The mixture is then melted at high temperatures in the furnace until it becomes a molten material, ready for formation. The type of glass this mixture will produce is known as soda-lime glass, the most popular glass for food and beverages.
Glass Forming Methods
Molten glass gobs are cut by a perfectly-timed blade to ensure each gob is of equal weight before it goes into the forming machine. The weight of a gob is important to the formation process for each glass container being made. The molded glass is created by gravity feeding gobs of molten glass into a forming machine, where pressure forms the neck and basic shape of the bottle. Once the neck finish and the general glass bottle shape has been achieved, the form is known as a parison. To achieve the final container shape, one of two processes are used.
Press and Blow Process
The Press and Blow process is the most commonly used method in glass bottle manufacturing. It uses an individual section (IS) machine, which is separated into varying sections to produce several containers of the same size simultaneously. The molten glass is cut with a shearing blade into a specific gob size. The gob falls into the machine by force of gravity. A metal plunger is used to push the gob down into the mold, where it starts to take shape and become a parison. The parison is then transferred into the blow mold and reheated so that the parison is soft enough to finish off the dimensions of the glass. Once the parison is reheated to blowing temperature, air is injected to blow the container into shape. Press and blow methods are typically used for manufacturing wide-mouth bottles and glass jars as their size allows the plunger into the parison.
Blow and Blow Process
The Blow and Blow process is used to create narrow containers. It also requires an IS machine, where gobs of molten glass are gravity fed into the mold. The parison is created by using compressed air to form the neck finish and basic bottle shape. The parison is then flipped 180 degrees and reheated before air is again injected to blow the container into its final shape. Compressed air is once again used to blow the bottle into its desired shape. Blow and Blow methods are best used for glass bottle manufacturing requiring different neck thicknesses.
Finishing the Process
Regardless of the process used, once the bottle has been completely formed, it is removed from the mold and transferred to the annealing lehr. The lehr reheats the bottes to a temperature of about 1,050 degrees Fahrenheit then gradually cools them to about 390F. This process allows the glass to cool at an even rate - eliminating internal stresses in the glass that could lead to cracking or shattering. Bottles are then subjected to careful inspections to ensure they meet quality control guidelines. Any bottles showing imperfections, including bubbles, cracks, or misshapen areas, are removed from the line and used as cullet. All remaining bottles are sorted according to size and type. The bottles are then packaged on pallets and prepared for shipping.
Keeping your freezer filled with homemade broth is a fantastic way to keep your home stocked with healthy convenience food. But after stewing and brewing all that broth, you need a simple, nontoxic way to store it.
Plastic containers can work fine in a pinch, but plastic food storage does come with some concerns about leeching chemicals. Pressure canning the broth in glass jars in another option, like a CBD flower jar, but requires more work and attention.
Place your jars in a cardboard box (like the one mason concentrate jar sets are sold in) before putting in the freezer. This allows you to easily keep some distance between them and can also be handy if you use a chest freezer. Or use a JarBox, a genius product!
Slip your jars into clean socks before putting them in the freezer. This prevents them from bumping against each other and breaking that way.
Try Glasslock storage containers. The glass is tempered, so it’s stronger and better able to handle temperature changes. They are pricier than canning or repurposed weed jars, but might be an investment you’d like to make since you can also cook with them.
Stick with jars that are designated as freezer-safe, like these pint-and-a-half wide mouth jars, or use smaller size jars like wide mouth pint, half-pint, and 4-ounce.
Glass Forming Methods
Molten glass gobs are cut by a perfectly-timed blade to ensure each gob is of equal weight before it goes into the forming machine. The weight of a gob is important to the formation process for each glass container being made. The molded glass is created by gravity feeding gobs of molten glass into a forming machine, where pressure forms the neck and basic shape of the bottle. Once the neck finish and the general glass bottle shape has been achieved, the form is known as a parison. To achieve the final container shape, one of two processes are used.
Press and Blow Process
The Press and Blow process is the most commonly used method in glass bottle manufacturing. It uses an individual section (IS) machine, which is separated into varying sections to produce several containers of the same size simultaneously. The molten glass is cut with a shearing blade into a specific gob size. The gob falls into the machine by force of gravity. A metal plunger is used to push the gob down into the mold, where it starts to take shape and become a parison. The parison is then transferred into the blow mold and reheated so that the parison is soft enough to finish off the dimensions of the glass. Once the parison is reheated to blowing temperature, air is injected to blow the container into shape. Press and blow methods are typically used for manufacturing wide-mouth bottles and glass jars as their size allows the plunger into the parison.
Blow and Blow Process
The Blow and Blow process is used to create narrow containers. It also requires an IS machine, where gobs of molten glass are gravity fed into the mold. The parison is created by using compressed air to form the neck finish and basic bottle shape. The parison is then flipped 180 degrees and reheated before air is again injected to blow the container into its final shape. Compressed air is once again used to blow the bottle into its desired shape. Blow and Blow methods are best used for glass bottle manufacturing requiring different neck thicknesses.
Finishing the Process
Regardless of the process used, once the bottle has been completely formed, it is removed from the mold and transferred to the annealing lehr. The lehr reheats the bottes to a temperature of about 1,050 degrees Fahrenheit then gradually cools them to about 390F. This process allows the glass to cool at an even rate - eliminating internal stresses in the glass that could lead to cracking or shattering. Bottles are then subjected to careful inspections to ensure they meet quality control guidelines. Any bottles showing imperfections, including bubbles, cracks, or misshapen areas, are removed from the line and used as cullet. All remaining bottles are sorted according to size and type. The bottles are then packaged on pallets and prepared for shipping.
Keeping your freezer filled with homemade broth is a fantastic way to keep your home stocked with healthy convenience food. But after stewing and brewing all that broth, you need a simple, nontoxic way to store it.
Plastic containers can work fine in a pinch, but plastic food storage does come with some concerns about leeching chemicals. Pressure canning the broth in glass jars in another option, like a CBD flower jar, but requires more work and attention.
Place your jars in a cardboard box (like the one mason concentrate jar sets are sold in) before putting in the freezer. This allows you to easily keep some distance between them and can also be handy if you use a chest freezer. Or use a JarBox, a genius product!
Slip your jars into clean socks before putting them in the freezer. This prevents them from bumping against each other and breaking that way.
Try Glasslock storage containers. The glass is tempered, so it’s stronger and better able to handle temperature changes. They are pricier than canning or repurposed weed jars, but might be an investment you’d like to make since you can also cook with them.
Stick with jars that are designated as freezer-safe, like these pint-and-a-half wide mouth jars, or use smaller size jars like wide mouth pint, half-pint, and 4-ounce.