Glass vs Plastic Carboys, which is better?

This debate has been going on since the introduction of plastic carboys made from PET. PET by the way stands for polyethelene terephthalate. There are very good arguments for going with either glass or PET, however, the right answer for you will depend on your own preferences. To help you out I have outlined the pros and cons of each here so that you can make an informed decision for yourself.

The Pros of Glass Carboys

By far the most convenient wine vessel is the glass carboy.

6-Gallon Carboy

There are two main advantages of glass over plastic carboys. First, you can scrub it clean with a carboy brush without scratching or pitting the glass. Second, there’s no possibility that glass is going to leech chemicals into your wine (a valid concern with plastic, more on that in a minute).

When taken care of properly a glass carboy can last for decades. In fact, the only reason to replace a carboy is if it breaks. Plastic carboys, by contrast, need to be replaced if they get scratched or dented. Some wine makers recommend replacing plastic carboys after about 7 fermentations or so regardless of whether or not it has been damaged in any way.

The Cons of Glass Carboys

One problem with glass is that it is brittle, it does not bend before it breaks. When it does break it shatters and you wind up with a pile of wine and glass shards at your feet, so there are safety concerns when using glass.

To make that last point even worse is the weight of a glass carboy. A typical 6 gallon glass carboy weighs around 19 lbs when empty. Add five gallons of wine to that and you’re talking about lifting and handling a 60 lb carboy.

Needless to say you’re going to have to be careful when moving a full glass carboy around. If possible have someone help you support it or even just spot you as you move it. Wear close toed shoes in case the worst should happen and the carboy goes down unexpectedly.

The Pros of Plastic Carboys

Here's a plastic carboy made from BPA free PET plastic.

Six Gallon PET Carboy

Clearly the there are a couple advantages to using plastic carboys. First they are not nearly as fragile as glass. If they get bumped or are dropped a few inches because you lost your grip it’s not going to explode into a thousand pieces.

A standard 6 gallon carboy weighs around 5 lb, almost four times lighter than a glass carboy. Thus a full plastic carboy will weigh around 45 lbs instead of 60 lbs. Yes that’s still heavy but that 15 lbs could mean the difference between dropping it and not dropping in some instances.

The Cons of Plastic Carboys

The most substantial drawback to using plastic carboys is the tendency for the plastic to get scratched. You can’t clean a plastic carboy with a carboy brush because the inside surface may get scratched. This may not seem like a big deal but even small scratches can become great places for spoilage micro-organisms to hide out. Using a sanitizer can’t even guarantee that all of the organisms are killed off before you add your wine to the container.

Another con is that plastic has a shelf life. As mentioned before some experienced wine makers recommend replacing plastic carboys after 5 to 7 uses whether or not they’ve got a lot of scratches.

The Issue of BPA in Plastics

Lastly, there is a concern that plastics can leech chemicals into your wine. The worst of the worst chemicals in plastics is Bisphenol A (BPA). It’s an endocrine blocker and carcinogen that can interact with foods that come into contact with this plastic (this is why you never use a hardware store bucket as a primary fermenter).

The National Association for PET Container Resources (www.napcor.com), however, asserts that PET contains no Bisphenol A (BPA), nor any heavy metals. This is why PET is considered a “food grade” plastic. So in this regard you can rest easier if you decide to go with a PET plastic carboy

Still, some are wary of plastic carboys because of the chemicals that went into producing them. You’ll have to use your own judgement here. PET is also used to make water bottles so if you’re good with those then a plastic carboy probably won’t bother you either.

A Cost Comparison

On average glass carboys cost about 50% more than plastic ones. Also, if you’re ordering glass carboys online the shipping can be much more as well given the difference in weight and how fragile they are.

Because glass carboys can potentially last for decades though there is a cost benefit to buying glass if you think you’ll be making wine for some time to come. If you’re getting started on a budget plastic is definitely the way to go.

Making the Decision

As you can see there are quite a few factors to consider here. Namely, the weight, durability, fragility, and cost. You’ll also have to square with your feelings regarding the chemical concerns with plastic.

I personally have used only glass carboys thus far in my wine making efforts. This stems partly from my desire to do everything in life “old school”. I believe that plastic carboys are safe to use with the proper care. My personal preference for long term storage, however, would be glass.

  • Gary

    I have been thinking about this as a new brewer i have made my first
    batch with 2 buckets, but for my next brew i am debating on glass or
    PET. my wine kit does say glass is better. due to budget constraint i
    could not get a carboy to start.

    • Hi Gary! I hear what you’re saying about budget constraints. When you first start out there’s so much to buy that it really adds up.

      You can always start with a plastic carboy and move into a glass one when it starts to get tired. Either way I think your wine will turn out well.

      • Gary

        Hi Matt, been to brew shop today and got glass carboy, was only £4-5 dearer, FV buckets were not clear so needed to get something as how could i see my wine clear. they are fairly heavy but got a handle with it.

        • Nice Gary! Being able to see your wine as it clears helps a lot. You probably already know this but most carboy handles aren’t designed to move carboys with wine in them. Just in case they didn’t tell you at the store 🙂

          • Gary

            i Matt, how do you manage to see through 5 gallon of red wine to see if its cleared or clearing, tried on mine and i can see bugger all through it lol

            cheers

            Gary

          • Hi Gary,

            Red wines are tough to see through. You can do one of two things to check on its clarity.

            First you could try taking a flashlight and pointing it toward the wine and then see if you can look through the carboy at the light. You’ll be able to see particles floating around.

            If your wine is too dark of a color for that then you’ll have to take a small amount of wine in a wine glass and hold it at a 45 degree angle over a blank piece of paper. In good light you’ll be able to see whether or not it is clear where the wine is deepest in your glass. It doesn’t take much and if you get too much it’ll be hard to see.

            Let me know how this works for you.

            -Matt

  • Gary

    No they didn’t. Will bear that in mind. Cheers Matt

  • george

    When I started making wine I bought one glass carboy from the wine supply store. The I would visit flea markets where I bought several more. I checked Craigslist (even in the city where my son lives and got 2 six gallon jugs). My neighbors go to ,yard sales a lot so I asked them to be on the lookout for me and they got me one 5 gallon carboy. I now have 8 five gallon and 2 six gallon jugs. I also have six one gallon jugs. If you have a natural foods store in your area (Earth Fare, Whole Foods or Fresh Market) you should be able to buy apple juice or cider in the Fall in gallon glass jugs. I got mine at Earth Fare. They have them every Fall. They range from $5 to $7 which is cheaper than buying a new empty jug. I paid $20 each for the 6 gallon and $10 for 5 gallon jugs, used. I also get my wine bottles from a local wine bar. I give them some wine and fresh fruit and vegetables on occasion and they are happy to save the bottles for me. I now have so many bottles that I will never have to buy more even if I keep making wine the rest of my life. This saves a lot money. You can make a degasser from a plastic clothes hanger to save even more. I have made my own wine racks. They are very rustic looking but they do the job very well. The wood was free (Craigslist) or visit a construction site and ask for scrap wood. There are lots of ways to cut the cost of supplies in wine making.

    • George, thank you very much for sharing these great ways to save some money while building a home winery! Purchasing all new glass carboys can certainly get expensive.

      I too have received used bottles from a winery. They were more than happy to let me have them and help out a beginner as they have to get rid of the bottles once used.

      -Matt