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Primary In A Plastic Bucket For 4 Weeks?

Is a typical plastic fermenting bucket too oxygen permeable to be used for a month-long primary? I know 3 weeks is typically fine, but something came up, and I might not be able to bottle until 4 weeks after primary began. Should I make an effort to bottle after 3 weeks or is 4 ok?

4 weeks is fine. I typically leave all my beers in primary buckets for 4 weeks and have never had any issues. Recently aged a stout in a bucket for 3months with zero signs of oxidation.

I might do that with the occasional lager and it’s fine. Many of my beers go 3-4 weeks (ale or lager) and there is no issue with this having to do with the plastic primary or anything else… autolysis is often stated as a reason not to do this but does not appear to show its face after just 4 weeks. I’d say you’re good.

The plastic buckets used for fermenting are food grade and pretty solid all around…aside from easier to scratch and that they discolor after a while, I think they’re as good as glass …easier to clean for sure!

I rarely go less than a month in the primary and rarely use glass. But treat your plastic right - no scratching! I use only soft cloths to clean them and retire them to alternate brew shop uses eventually (which is due to excessive staining and a fear, perhaps irrational, that there could be some leaching from batch to batch at some point).


I go 3 to 5 weeks in primary. No problems at all. Some homebrewers have gone longer than that.

You’ll probably be fine. Personally I don’t use plastic anymore, as I know prolonged storage in plastic can indeed cause issues. But assuming you have new unscratched buckets, you’ll most likely be fine.

Dave, can you expand on the issues you have experiences or feel happen and at what point you have seen or feel these issues arise?

I have experienced everything, from severe oxidation (tastes like cardboard) to contamination (tastes sour or like turpentine) to yeast autolysis (tastes like rubber or burnt matches). The yeast autolysis is purely my own fault – if you leave the beer in primary for 3 or 4 months, you are at risk of autolysis. But 1 or 2 months, you are safe. The other issues are also due in part to laziness but with plastic you are much more prone to it. Oxidation can kick in at 2 or 3 months, and happens because plastic can breathe a little bit whereas glass cannot. Contamination is anyone’s guess but can happen due to old scratched plastic, a previous contaminated or soured batch in the same bucket, or dust in the air or fruit flies that find their way in through some tiny opening that you didn’t know about. And once a bucket becomes contaminated, there is no sanitizer in the universe that can kill every single cell of it, and you can get contamination again using the same bucket.

I have made all these mistakes so that you don’t have to, or so that you will know if you are doing the same.

But again I say, if you have reasonably new buckets (less than a couple years old) and have never had any issues, you should be safe to store your beer in there for at least a month if not two. But don’t go three months or you are at much greater risk of all of these off-flavors. And if you ever detect any of the above issues at all… it would be best if you throw the bucket away and start over, and do not attempt to use the same bucket for another fermentation or else you are at close to a 50/50 risk of problems.

So again I say… glass is the solution I have finally come to in my own brewing.

[quote=“dmtaylo2”] … And once a bucket becomes contaminated, there is no sanitizer in the universe that can kill every single cell of it, and you can get contamination again using the same bucket.


Heat? You can pour boiling water into a fermentor bucket. That won’t sterilize and kill spores like an autoclave, but ought to kill the kinds of buggers that affect/infect our beers.


As an aside, I have gotten away from glass because I don’t care to carry it, clean it, etc. and when they break (not if… when), it’s quite frightening. I have busted numerous 5-gal and 6½ gal glass carboys and I would like to know that I won’t see another one. I primary in plastic buckets and secondary in Better Bottles. Do things properly and you will not see contaminations. Dave, I hate to say it but 3-to-4 months in primary? Did you leave on a space mission or were you in a coma? I’m not trying to be douchy but that is a crazy-long time to have a beer in primary.

Laziness and forgetfulness. Ever bottle a batch of barleywine or RIS and say to yourself, dang, this beer would probably be good about 6 months from now, so you stow it in a back corner someplace and totally forget about it… then stumble upon it again like 2 years later? That’s sort of what I’m talking about… except in the primary. Or you say to yourself, nah, I don’t feel like racking that beer today, but I’ll take care of it tomorrow… then say the same thing the next day… and again the day after that? Yeah, that was me… But I got better.

Don’t know if I ever tried heat treatment. Maybe it would work. But not really worth the risk either IMHO.

Dave, thanks for expanding on the topic.

I agree with the point that if you have had an infection, toss the bucket.

Yes, if you have fruit flies and such, major problem. Glass or plastic.

I’ve left a beer in a glass carboy for 4-6 months before that soured. Probably because I let the air lock go dry. Who knows what made it’s way in.

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