If you're getting into home winemaking, one of the first equipment choices you'll make is whether to use a glass carboy or a plastic carboy. Both have their place, and the right choice depends on how much wine you're making, what stage of fermentation you're in, and how you prefer to handle your equipment.
In this guide, we'll compare plastic vs glass carboys, explain the main advantages and disadvantages of each, and help you choose the right size for your application. We'll also touch on old-school demijohns, which are closely related to modern glass carboys and still popular with many traditional winemakers.
What Is a Carboy?
A carboy is a large fermentation vessel commonly used for wine fermentation, secondary fermentation, ageing, clearing, and storage. In home winemaking, carboys are most often used with a stopper and airlock to protect wine while still allowing fermentation gases to escape.
On our site, we carry these carboy options:
Glass Carboys: Traditional, Durable, and Great for Ageing
Glass carboys are the classic choice for home winemaking. For many winemakers, they are still the gold standard for secondary fermentation and long-term ageing.
Advantages of Glass Carboys
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Non-porous: Glass does not absorb odours, flavours, or oxygen.
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Excellent for ageing: Because glass is impermeable, it is ideal for longer-term storage and ageing of wine.
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Easy to monitor: You can clearly see sediment, clarity, and fermentation activity.
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Traditional and proven: Glass has been used for generations in winemaking and is trusted by experienced hobbyists and traditionalists alike.
Disadvantages of Glass Carboys
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Heavy: A full glass carboy is not easy to move, especially in larger sizes.
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Breakable: Glass can crack or shatter if dropped or mishandled.
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Harder to transport: If you need to move wine around often, glass is less convenient than plastic.
Plastic Carboys: Lightweight and Easy to Handle
Plastic carboys are popular because they are easier to move, easier to work with, and less intimidating for beginners. A good PET plastic carboy can be a very practical option for active fermentation and general handling.
Advantages of Plastic Carboys
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Lightweight: Much easier to carry, clean, and move than glass.
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Safer to handle: Plastic does not shatter like glass.
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Convenient for primary fermentation: Especially useful when you need to move or rack batches more often.
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Beginner-friendly: Many home winemakers like plastic for its ease of use.
Disadvantages of Plastic Carboys
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More oxygen permeability over time: Plastic is generally better for shorter- to medium-term use rather than very long ageing.
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Can scratch: Rough cleaning can leave scratches that are harder to sanitize properly.
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May retain odours over time: With repeated use, plastic can hold onto smells more than glass.
Glass vs Plastic Carboys: Which Is Better?
Neither one is automatically better for every situation. It depends on how you plan to use it.
Choose glass if:
- you want the best option for ageing wine
- you prefer traditional winemaking equipment
- you want a vessel that does not absorb odours or oxygen
Choose plastic if:
- you want something lighter and easier to handle
- you are doing active fermentation or frequent transfers
- you want a more convenient option for everyday use
Many winemakers end up using both: plastic for some stages of fermentation and glass for clearing or ageing.
What About Demijohns?
If you've been around winemaking for a while, you've probably heard the term demijohn. In many cases, people use the words demijohn and carboy almost interchangeably, especially when talking about traditional glass vessels.
Old-school demijohns are essentially the traditional ancestors of today's glass carboys. They are often associated with classic home fermentation and old-world winemaking setups. If you like that traditional style, a glass carboy gives you that same dependable, time-tested feel, while still fitting modern home winemaking equipment like standard stoppers and airlocks.
What Size Carboy Do You Need?
Carboy size matters because you want enough room for your batch while also keeping headspace under control. Too much extra space can expose wine to more oxygen than necessary, especially after active fermentation has slowed down.
3 Gallon Glass Carboy
A 3 gallon glass carboy is ideal for:
- small experimental batches
- fruit wines
- mead or specialty batches
- splitting larger batches for different yeast or oak trials
- topping up or storing a smaller volume after racking
If you're not ready to commit to a full 5 or 6 gallon batch, 3 gallons is a very manageable size.
5 Gallon Glass Carboy
A 5 gallon / 19L glass carboy or 5 gallon glass carboy is commonly used for:
- secondary fermentation
- clearing wine after primary fermentation
- ageing a standard batch after losses from sediment and transfers
- finished wine storage before bottling
This size is especially useful when your original batch starts larger, then drops closer to 5 gallons after fermentation, racking, and sediment loss.
6 Gallon Plastic Carboy
A 6 gallon / 23L PET plastic carboy is a great choice for:
- standard wine kit batches
- primary fermentation with some extra working room
- winemakers who want a lighter vessel
- general-purpose fermentation and handling
Six gallons is one of the most common home winemaking sizes because it gives you a practical amount of capacity for typical batches.
Which Carboy Size Is Best for Each Application?
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3 gallon: small batches, test batches, fruit wine, mead, or splitting a batch
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5 gallon: secondary fermentation, ageing, and storing wine after racking
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6 gallon: standard batch fermentation, especially when you want a bit more volume capacity
Final Thoughts
Both glass and plastic carboys are useful in home winemaking, and most experienced winemakers eventually appreciate the advantages of each. Glass is excellent for traditional winemaking, long-term ageing, and oxygen protection. Plastic is easier to move, easier to handle, and very convenient for active use.
If you want a more traditional setup, glass carboys and demijohn-style vessels are hard to beat. If you want convenience and easier handling, plastic makes a lot of sense. The best choice comes down to your batch size, your storage plans, and how you like to work.
Browse our selection of carboys here:
