This 5-gallon glass carboy is the perfect size for a secondary fermentation. You will want your batch to age for a long time and this bad boy leaves minimal head space that is ideal for a 5-gallon batch. Customers come back again and again for these glass carboys because our glass is heavy-duty, doesn't hold odors or scratch like plastic, and won't break down over time. Plus, it's fun to watch the fermentation take place inside. 5-gallon size is ideal for secondary fermentations. Easy to clean Uses a 6.5 stopper or a universal carboy bung (sold separately).