Fermentation is a process where beer develops its alcohol content and carbonation. A carboy is used during this process after being transferred from the fermentation bucket. It is used to store the brew in a cool, dark environment away from light and heat. Whether you are a home brew beginner or seasoned brewer, this 6 gallon carboy is essential to your craft. Its solid glass construction will last a lifestyle if properly cared for. It is vital to be sure to clean and sanitize your carboy when not in use. Note: 6 gallon carboys are ideal for 5 gallon batches of brew, leaving enough "head room" at the top.