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.
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.
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.
Anytime you freeze in a glass jar that has shoulders, you have to make sure that the broth stays below the shoulders while it freezes and expands. That means that the broth should be 2-3 inches below the shoulders before you stick it in the freezer.
3. Use Wide Mouth Mason Jars
Instead of using regular qube jars and worrying about the shoulders, you can use wide mouth mason jars.
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.