Enjoy the beer that you deserve.
What it does :
Carboys are used by homebrewers to contain fermentation. Typical volume is 5 gallons (18.9 liters), with extra head space to accommodate the foaming that comes with fermentation.
What it is:
A glass carboy is a large cylindrical container with a narrow top opening.
How it works:
One advantage of glass is that you can easily see the progress of the fermentation. Also, the non-permeable and scratch-resistant nature of glass makes sanitation easier. However, they can be a little challenging to clean because of the limited access provided by the small opening. The carboy should be kept in a dark place or covered during fermentation, when you are not anxiously checking on your beer's progress, that is.
Glass carboys are used for the cold side of brewing (e.g. fermentation, bottling, and packaging). Carboys come in direct contact with the beer during the critical fermentation stage. So, glass carboys should be sanitized before use to prevent contamination.