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
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
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.