Plastic Big Mouth Bubbler

Review: Plastic Big Mouth Bubbler

The sad remains of a broken carboy, and the story of the lucky garage floor that got to taste the beer...
The sad remains of a broken carboy, and the story of the lucky garage floor that got to taste the beer… (Note: this is not a picture of MY actual broken carboy. I was too dumbfounded to grab my camera.)

I’ve always fermented using standard glass carboys. I have two 6.5 gallon glass carboys and two 5 gallon glass carboys. At least, I did… until I dropped one on the floor of my buddy’s garage. This was my first experience with a catastrophic failure at the end of a brew day, and cleaning up the pieces afterwards was not fun. That got me thinking about fermenters. I had been dreaming of a nice heated and cooled conical fermenter, but at around $2,000+ for a prefabricated one, it would take quite a bit of convincing to add that to the home brewery. On the other hand I could go cheap and try simple plastic buckets with lots of head space. But as much as a stainless conical fermenter sounds awesome, or a plastic bucket seems like an inexpensive option, I like the convenience of being able to watch my fermentation in a glass carboy.

Plastic Big Mouth Bubbler

Big Mouth Bubbler™ - 6.5 Gallon Plastic Fermentor
Plastic Big Mouth Bubbler – 6.5 Gallon Fermentor

Enter the curious Plastic Big Mouth Bubbler from Northern Brewer. It comes in both 5 gallon and 6.5 gallon sizes, both of which have a 5.5-inch wide mouth. On top of that, you can get either a single port or dual port lid. This allows for some flexibility in sampling, adding a thermowell, or combining a blowoff tube with an airlock. In addition it boasts a punted bottom that supposedly seats an auto siphon perfectly above the trub for clear racking. So… I ordered two to try out in my upcoming brew session…

Initial Impressions

I ordered two 6.5 gallon fermenters from Northern Brewer on May 18. I also ordered a harness, a dual-port lid, and a fermometer for each one. Everything arrived on May 20th safe and sound. When I took the Plastic Big Mouth Bubbler out of the box I was surprised at how light it really felt. It was night and day compared with the usual weight of a glass carboy. It came with a single port lid and a securing ring. The dual port lids came packaged separately.

Cross-straps for the Harness
The harness uses cross straps for stability.
6.5 Gallon Plastic Big Mouth Bubbler
6.5 Gallon Plastic Big Mouth Bubbler with harness and Fermometer

The first thing I did was to put the fermometer on and fit it with the harness. I had to double check online, but once I figured it out and crossed the blue handles over the neck it made more sense. The harness gave the fermenter a nice sturdy feel and made it very easy to carry. I didn’t want to waste water by filling it up just to check how it handled, so I will have to post an update on brew day when I finally have some beer in it.

Underside of the lid
The underside of the lid has a rim for secure centering.
Lid and securing ring
The dual port lid and securing ring
Inside of the ring
The inside of the securing ring has no gasket.

The lids are interestingly designed. The ported lids are made of a single flat piece with a small lip on the bottom of it. The lip helps center the lid on the neck of the bottle so there’s no guesswork. The lid is secured in place with a separate blue plastic ring that holds the lid very tightly. There is no gasket to replace, which is an improvement over the glass Big Mouth Bubbler. The threads in the ring are fairly large and wide which should make cleaning easy (a solid soak in PBW will likely take care of it).

Silicone Stopper
SIlicone stopper in the single port lid
Stopper From Above
The stopper from above

At least in a non-brewing situation the #6.5 silicone stopper fits quite securely and snugly in the port hole. Both the single and dual ports are the same diameter and fit the stopper the same.

Autosiphon in place
The Autosiphon in place
Punted bottom
The punted bottom up close
Punted bottom holding an Autosiphon
The punt holds the auto siphon above the bottom

The ports also fit a large (1/2 inch) auto-siphon that can be directed down onto the punted bottom in the center of the fermenter. I’m not sure if the punt adds stability or was added specifically for a racking cane/auto-siphon, but it holds the siphon about an inch or two above the bottom. This should allow for minimal disturbance of the yeast cake and trub when racking to a secondary fermenter, bottling bucket, or keg.

Cleaning Test

The Plastic Big Mouth Bubbler has a spacious 5½ inch diameter mouth that allows for easy cleaning access. The wide mouth and light weight will undoubtedly make manual cleaning a relatively easy task. But I was curious how well it worked with a carboy washer. I use Mark’s Keg and Carboy Washer for much of my brew day cleaning and sanitizing. I love this piece if equipment because it makes my brew day preparation and cleanup so much easier.

Full View on the keg washer
On the Keg Washer with the silicone gasket
On Mark's Keg Washer
Closeup on the silicone gasket

The Keg Washer has a central stand that is about 5.5 inches in diameter, the same as the Plastic Big Mouth Bubbler. On top of the central stand is a silicone gasket that is used to help stabilize the keg or glass carboy. The Plastic Big Mouth Bubbler actually fits right on that gasket and stays quite solidly in place. Even when I turned the water on the fermenter stayed in place (see video below).

Full view on the keg washer without the gasket
On the Keg Washer without the gasket
On the keg washer without the gasket
Closeup on the neck

I also took off the gasket to see how far the fermenter would drop down. The fermenter sank down onto the stand about an inch or so, and the fit was pretty tight. I’m concerned that there would be about a 1-inch ring on the neck that would not get cleaned like this. One thing I did realize, though, is that the Plastic Big Mouth Bubbler is so light I can hold it quite easily over the washer stream, without resting it on the stand. While this would take more effort than the “set it and forget it” of a smaller-necked carboy, it would still get the Plastic Big Mouth Bubbler quite clean.


My initial impression is very positive! The wide mouth, lid access options, and easy carrying harness are fantastic! The only potential downside I see is whether the plastic will hold a full batch of beer without flexing too much. I’m really excited to begin using the new fermenter. After checking it out I am optimistic about using it for brew day. I will be brewing a Bavarian Helles sometime this week so that will be a good chance to see how the new Plastic Big Mouth Bubbler handles a batch of beer and fits in the freezer fermentation chamber. Stay tuned for an update to this review on Brew Day!

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Last updated: May 27, 2014 at 21:33 pm

2 thoughts on “Review: Plastic Big Mouth Bubbler”

  1. These are much taller than a better bottle, right? It might be a solid investment, just because it’s less wide, if it can fit 2 inside of a fermentation chamber instead of one.

    Does it scratch easier than a Better Bottle?

    1. I am not sure of the dimensions compared to a Better Bottle, as I don’t have one, but I can say that I can snugly fit two Big Mouth Bubbler’s and two Corny Kegs in my 7 cu. ft. chest freezer.

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