Glass products are used by melting one or all of three rather inexpensive and readily available ingredients including sand, soda ash, and lime. Additives are added to the mixture for strength and for altering the color. The mixture is heated to over 1000 degrees Fahrenheit, which ultimately turns the mixture in a syrup like matter known as molten glass.
Bottles, jugs, carboys, and demijohns are made in one of two ways from here including air blown, and molded or pressed. For the air blown method, air is blown through a tube into the center of the molten glass. A balloon begins to form from the pressure and increases in size. This is done within a mold, and as the balloon expands to the reach the mold, the outer shape of the vessel is formed. Alternatively for the pressed or molded variation, there are molds the the contain both the outer and inner shape of the glass. The molten glass is poured into the mold and allowed to consume all of the cracks and crevasses, forcing the air out. In both cases the mold is put into an annealing oven to cool slowly. A rapid reduction in temperature will result in cracking or shattering of the glass. The molds are made up of 2 or more pieces that come apart, leaving a beautiful piece of art.
The larger carboys of this type have little demand. Glass carboys are primarily suited for the wine and beer hobbyist, and as you might suspect this does group of people do not lead global trade discussions. For any vessel or container that is applicable to the industries with labs, or those with cleaning and storage needs, there is a plethora of manufacturers and products. Namely in the plastics and metal drums space. A 5 gallon glass carboy, however, is not ideal for these applications. Therefore the number of manufacturers for large glass containers in the space have dwindled over time as plastics offer cheaper production costs, better durability, and are formed into different shapes suiting those industries. This has caused a fairly recent spike in prices as one of the major manufacturers in North America and Mexico (Vitro Packaging Inc) has stopped production.
Glass carboys can be found in three basic varieties including jugs, carboys, and demijohns. The vary both in shape and size.
Jugs come in 1/2 gallon and 1 gallon sizes. They can be used in the same way as larger fermentation containers with the use of a fermentation lock or airlocks. The size itself will offer some advantages and disadvantages. The small form is ideal for experimentation using different yeast cultures on a small scale. A singe batch can be split up, different yeast strains applied, and allows for a very convenient way to test batches without the commitment of using a full batch. Also the size of the containers allows for it to be conveniently placed in a refrigerator for fermenting lagers which require lower temperatures. They are generally equipped with a handle making for easy transport and movement. And once fermentation is complete, they are reusable and great for temporary storage of beer for taking some to share with friends.
The same advantage in some ways is also a disadvantage. The size is not ideal for fermenting a full batch of brew, for example 5 gallons. It will create more work to deal with numerous jugs, there will be more variation due to yeast distribution, and you will be investing in airlocks. Its just not going to be a long-term best practice for brewing.
Jugs have a much wider array of usage by many industries, and with this demand, there are many manufacturers. This helps with driving prices down. They come in different shapes and colors. You will also find varying wall thickness. A general idea for pricing can be found below.
|Glass Jug||0.5 gallons||$2.75 - $7.95|
|Glass Jug||3 gallons||$3.20 - $6.95|
Carboys are the term for larger vessels and can be found in sizes ranging from 2.5 gallon to 6.5 gallon. The thickness of the walls are generally 1/4" thick, but variations will be found, especially in older bottles. There are variations in the shape of the carboys and include both smooth outer texture and ridged. The ridged texture is especially helpful when handling the carboy when wet, as it helps with grip. Also, some glass carboys can be found with a greenish tint.Below is a table of available glass carboy sizes, and illustrates some prices that can be found around the web.
|Glass Carboy||2.5 gallons||$12.99|
|Glass Carboy||3 gallons||$17.92 - $29.95|
|Glass Carboy||5 gallons||$21.90 - $35.90|
|Glass Carboy||6 gallons||$23.89 - $44.95|
|Glass Carboy||6.5 gallons||$24.89 - $47.95|