[blair.streit]

How did that person reach the conclusion that it was infected due to fermenting in plastic?

Yeah that diagnosis seems suspect. If the comments were misinterpreted I could see how a suggestion (i.e. "check plastic vessels for scratches") could be taken as a prescription. Were these judges comments on a competition scoresheet, or just a judge tasting your beer and offering an opinion?

I am not aware of any specific contaminants that are more likely to exist in plastic vessels. The comments about scratches being potential hiding places are certainly valid, but as plenty of accomplished brewers have stated here, they can and do regularly make great clean beer with plastic.

The most common off flavors I can think of that are associated with the word plastic (but not with fermenting in plastic) are:

1) Chlorophenols - often described as tasting like plastic or medicinal flavors; common causes are related to chloramine or chlorine (usually from water or incomplete rinsing of chlorine-based sanitizers)

2) Actual plastic taste from hot liquid in vinyl tubing

Of course there are contaminants like wild yeast that can have a plastic tasting off flavor as well.

Before changing up a bunch of equipment, I recommend investing a little more effort into running down what the initial off flavor was and any process differences that could account for its absence in your newer beer.

[Ale Farmer]

I'll join the chorus in defending plastic. Occasionally I'll use a glass carboy for a secondary, and it's work out just fine--but the extra care and extra weight makes the work far less enjoyable than plastic.

[crakers540]

I have only used glass carboys since I started brewing in 1990.  I think the only potential problem with plastics is if you are overly aggressive in cleaning and make major "gouges" in the plastic. Those scratches or "gouges" can leave hiding places for microbes, regardless of the sanitizing regiment.  I plan on moving to the safer, lighter plastic carboys once I get permission to replace my glass babies.....

[udubdawg]

If this comment was on a blind competition scoresheet, then that Beer Judge is a lot more suspect than your plastic.

[Lazy Ant Brewing]

I've been using big mouth bubblers without any problems.  I just use a soft rag and PBW to clean before sanitizing.  I've been brewing for about 3 years and have never had a single infected bottle.

[Joe Sr.]

I've been using Better Bottles for well over 10 years.  They don't impact flavor and if you clean them gently (soft cloth, not bottle brush) they will last a looong time.  I haven't replaced one yet.

I ditched all of my glass in the past 5 or 6 years when I cracked a carboy with one of my kids nearby.  I don't need the risk.

You can mitigate the risk, and I did for many years, but it's always there.

[denny]

I have only used glass carboys since I started brewing in 1990.  I think the only potential problem with plastics is if you are overly aggressive in cleaning and make major "gouges" in the plastic. Those scratches or "gouges" can leave hiding places for microbes, regardless of the sanitizing regiment.  I plan on moving to the safer, lighter plastic carboys once I get permission to replace my glass babies.....

Ya know, scratches in plastic have been cited for years as a potential problem and I just don't believe it.  What can be in a scratch that Craftemeister alkaline cleaner and StarSan can't get to?

[Stevie]

I have only used glass carboys since I started brewing in 1990.  I think the only potential problem with plastics is if you are overly aggressive in cleaning and make major "gouges" in the plastic. Those scratches or "gouges" can leave hiding places for microbes, regardless of the sanitizing regiment.  I plan on moving to the safer, lighter plastic carboys once I get permission to replace my glass babies.....

Ya know, scratches in plastic have been cited for years as a potential problem and I just don't believe it.  What can be in a scratch that Craftemeister alkaline cleaner and StarSan can't get to?

I certainly believe it can be an issue, and it is easy enough to test if one has the equipment to do so. Maybe it isn't an issue in practice considering the amount of yeast we tend to use. I still take precautions to avoid scratches. I don't use buckets these days, but when I did I avoided nesting them to prevent scratching the inside.

[fmader]

Are we cleaning our plastic fermenters with swords? How are we getting these gouges and scratches? Let's correct the source of the problem instead of blaming plastics. If you are getting scratches and gouges in your plastics due to cleaning, you need to rethink your cleaning regimen.

[Joe Sr.]

Are we cleaning our plastic fermenters with swords? How are we getting these gouges and scratches? Let's correct the source of the problem instead of blaming plastics. If you are getting scratches and gouges in your plastics due to cleaning, you need to rethink your cleaning regimen.

I used a standard bottle brush on my first Better Bottle.  You can see where it was scrubbed, but there are no gouges.

It still functions perfectly well as a fermenter.  I take care to be sure it's well cleaned and sanitized, but nothing much beyond what I would do anyway.

I have enough others that I can keep the old one in reserve.  Years ago I had two batches that got infected.  When I tried to isolate the cause there were enough other batches that went through that fermenter and didn't get infected that I could rule out the fermenter as the problem.

[fmader]

Are we cleaning our plastic fermenters with swords? How are we getting these gouges and scratches? Let's correct the source of the problem instead of blaming plastics. If you are getting scratches and gouges in your plastics due to cleaning, you need to rethink your cleaning regimen.

I used a standard bottle brush on my first Better Bottle.  You can see where it was scrubbed, but there are no gouges.

It still functions perfectly well as a fermenter.  I take care to be sure it's well cleaned and sanitized, but nothing much beyond what I would do anyway.

I have enough others that I can keep the old one in reserve.  Years ago I had two batches that got infected.  When I tried to isolate the cause there were enough other batches that went through that fermenter and didn't get infected that I could rule out the fermenter as the problem.

Yeah. I soak mine in Oxiclean for a few days, then hit them with a "red" bottle brush, which is designed for plastics. Occasionally, I'll ball a wash rag up, shove it in the carboy, and shake it all about when I get stubborn debris. Usually a nice long soak does the trick.

[Biran]

I use a Speidel 7.9 gallon fermenter and love it.  The head room eliminates the need for blow off.  I have not had any problems with infection in over two years.

[ynotbrusum]

I use plastic, mostly, but glass for long term sours in a solera process that includes blending with a wood aged barrel.  I just recently upgraded to a couple stainless bucket type fermenters and I expect those to be my preferred route, because I can boil water in them to sanitize, if I so choose.  But I will likely do that only after souring in them, if I ever do that, which at present would not be on purpose....

[ethinson]

What is the general consensus on plastic fermenters (for primary) in terms of the risk of infecting a batch? I have used plastic better bottle and big mouth bubbler, and the last couple of batches produced an off-flavor that a beer judge identified as a contaminant due to fermenting in plastic. I purchased a glass 6.5 gal fermenter and fermented an IPA that tasted great. The extra weight of the glass added a whole dimension of complexity the the brew day. Should I pitch the PET? Thanks.

Alex

How did that person reach the conclusion that it was infected due to fermenting in plastic?

I was about to ask the same thing.  Do you remember if this was a BJCP ranked judge? Judges should never assume to know how something was produced.  They are assuming you fermented in plastic, and in this case they were right, but that was nothing more than a lucky guess.

I've had problems caused by lots of other things, underpitching, fermenting too hot, dirty bottles etc, but all of those things would have still happened if I fermented in glass.  Sounds like to me you got some bad feedback.  For most infections you should just make sure you're cleaning and sanitizing well as the others have said and you should be fine. 

[Indy574]

I'll join the chorus in defending plastic. Occasionally I'll use a glass carboy for a secondary, and it's work out just fine--but the extra care and extra weight makes the work far less enjoyable than plastic.

Same here. I have a glass carboy I use every other time. The weight does suck, I put it in a milk crate to help move it around.