We recommend this larger-capacity 6-gallon carboy for use as a secondary fermenter , especially when brewing lagers or high-gravity beers. It can also be used as a primary fermenter for 3-gallon batches of wine. Glass carboys are great for fermenting because they never scratch or break down over time. Plus, glass does not hold odor, which could impact taste. This carboy uses a #6.5 stopper or a small universal carboy bung.Caution: This fermentor is a large hand-formed glass item that can be easily damaged if not used with proper care and handling. It may have variations in shape and thickness, and will show the normal bubbling characteristics of hand-formed glass. Extreme changes in temperature or sudden contact with hard surfaces may cause glass to crack. Handle with care–we strongly recommend using the Brew Hauler for increased safety and ease of handling.Dimensional Shipping Weight applies.