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Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor


SKU# U41965


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Big Mouth Bubbler® Plastic is a virtually indestructible fermentor, equipped with 3” thick anti-flex ribs, a punted bottom and decreased base diameter for extreme strength and durability. Its smaller footprint preserves precious brew cave space and allows for convenient storage inside a standard brewing bucket.

Included: Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor, single-port universal lid.
Required: Small Universal Stopper & airlock. Configure options below.

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Big Mouth Bubbler Plastic - 6.5 Gallon   +$29.99
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Big Mouth Bubbler™ - 6.5 Gallon Plastic Fermentor

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  • Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor
  • Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor
  • Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor Lid


Product Details

Superior to a carboy, Big Mouth Bubbler® Plastic prevents off-flavors by enabling you to keep the lid on during testing and transfer, avoiding exposure to oxygen with standard-sized ports that can accommodate most fermentation-monitoring equipment.

The punted bottom promotes crystal-clear beer by efficiently settling out yeast from finished fermentations. Graduation marks make volume measurement instant and effortless. And, of course, its revolutionary wide mouth eliminates the nightmare of cleaning and sanitizing by giving you direct hands-on access to attack crusted krausen, while simultaneously offering unlimited flexibility in dry-hopping and flavor additions.

*The new Big Mouth Universal Lid (included) fits all Big Mouth Bubbler® Fermentors. The Big Mouth Bubbler® Universal Lid is just like a traditional carboy bung, only bigger! Just as easy to sanitize and set in place too. Ribbed silicone rings ensure a positive seal to keep out pests, while the non-threaded design allows the lid to move preventing an out-of-control fermentation from dangerously pressurizing your fermentor.

The optional Dual Port Lid allows for the use of a temperature controller probe. The ThermoStar Dual-Mode Digital Temperature Controller with optional 12" stainless probe ensures precise and repeatable fermentation temperatures!

Lid port works with our Small Universal Stopper or a standard 6.5 rubber stopper.

Important Note: Do not fill any Plastic Big Mouth Bubbler® fermenters with very hot liquid - temp should not exceed 140 degrees Farenheit (60 celcius)

BIG MOUTH BUBBLER® Product Specifications:
Capacity:5 gallon6.5 gallon
Height (w/lid, closed):22"23"
Fermentor Material:PETPET

Note: We recommend a soft cloth for cleaning the inside. Standard carboy brushes will scratch plastic fermenters leaving places for grime to hide. A warm cleaning solution will suffice. Do not use hot water on plastic fermenters of any sort. The Big Mouth Bubbler® is compatible with a standard carboy dryer when the dryer is used inverted.

*Pro Tip: Save your box and use it as a cover for your fermenter!

6.5 Gallon fermenters are perfect for the primary stage of beer or wine fermentation. The extra head space allows for the production of krausen on a 5 gallon batch of beer. Also available as a 5-gallon secondary fermentor.
3.6 / 5.0
153 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
Don't buy until they solve the lid problem!!!
Do not buy a big mouth bubbler until they solve the lid issue! I have two of the original big mouth bubblers and love them. Easy to clean and the screw on lids worked well in my opinion. Others say they leak, but if the seal does leak a little it is just the CO2 from fermentation leaking out. I purchased a replacement lid that has two ports. The new lid popped out during primary fermentation and exposed the entire batch to open air. Not cool!!!! They spin this as a feature to avoid bursting from overpressure but that is a poor attempt to hide a fundamental flaw in their design. The big mouth bubbler is the right tool for the job with a proper lid, but they don’t sell a proper lid at the moment that I am aware of. Don’t buy it until they do!
November 20, 2017
over 2 years ago
I didn’t listen to the more than 20% of the people who bought this, and gave it a 1 star. I figured “oh, they must be doing it wrong, that’s not going to happen to me.” Well, I was wrong, and here I am adding to the 1 star reviews to this terrible product.

With the bubbler empty, and NO CO2 pressure from fermentation, the lid will work it’s way off. Period. It’s not a factory defective lid or bubbler I received, because I stupidly bought 3 of them, and they all do the same thing.

Northern Brewer’s “answer” to this, is to tell you that "you're doing it wrong". You have to let the lid air-dry first. This is their desperate attempt at damage control for the flood of negative reviews pouring in about this defective product. First of all, it doesn’t make any sense to use a no-rinse sanitizer on your lid, and then let it sit in the open air for 12 hours drying and then using it on your carboy. Secondly, even if you had a dry lid, and dry seal (the seal is most of the problem) if the carboy mouth is wet, it does the exact same thing. Are you really going to let your carboy air-dry for a couple days before brewing, just so the lid will stay on???

Bottom line: This is a terrible design, it doesn’t work, and the company won’t admit it. You don’t sell a professional product to your consumers, and then have to tell them to go through elaborate “work-arounds” just to get it to work. Bad business. Ruined beer.
November 14, 2017
Response from Northern Brewer
Thank you for taking the time to write this review. We are sorry that you are not totally satisfied with your Big Mouth Bubbler. We will have Customer Service contact you to work out a resolution. We suggest following the manufactures instructions for all sanitizers. The last thing we want is anyone to have ruined beer.
November 16, 2017
Todd JStaff
Horrible Disappointment
This product has a horrible problem with the lid. It does not stay in and pops off easily. There isn't a solution to the problem without rigging it. In my mind something you pay for should just work. I would not recommend it and will not be buying another unless they fix the lid issue. I would rate it 4 stars or even 5 if the lid worked correctly. You have easy to read graduations and are able to reach in and thoroughly clean it. I really wanted this to work but am so disappointed.
October 6, 2017
Response from Northern Brewer
I would sanitize the lid and let it air dry a bit before inserting. Press one side of the lid in first, then the opposing side. Lift up the lid in places until you see and feel the ribs on the lid gasket "lock" into place. It should feel noticeably tight once you do so.
October 7, 2017
William RStaff
Lid needs to be screwed.
Great product, total failure of a lid. Lid pops up and needs to be weighted down.
September 30, 2017
Listen to what they all say..
"Bigmouth", whaaat?! Its the bigmouth that's what make it special, right? But, who cares if it spoils your entire brew?! And yes I'm talking about the lid, like everyone else..

Believe 'em folks... Aside from super glueing it on, I've tried about everything, yet every time I go to check on my brew the lid has popped off leaving my everything open to the elements. Guess that explaines the off flavors I've had these past couple rounds...

It's a plastic jug (Not that hard to find).. with a REALLY crappy lid.
September 10, 2017
7 months ago
Response from Northern Brewer
I'm sorry to hear about the lid issues you're experiencing with your Big Mouth Bubbler. There are a few tricks that can help get you bubbling away happily.

First, I would sanitize the lid and let it air dry a bit before inserting. Press one side of the lid in first, then the opposing side. Lift up the lid in places until you see and feel the ribs on the lid gasket "lock" into place. It should feel noticeably tight once you do so. If a tight fit is not attainable with the normal insertion technique above, you're still in luck. Remove the lid, take the gasket off, and reinstall the gasket upside down. The ribs on the gasket will engage in a much tighter manner. You'll still want to install it according to the above instructions, but I think you'll find that it grabs much more.
September 20, 2017
Laura EStaff
Looking for the PERFECT fermenter?
This isn't it! It's anything but rigid when full and you have to be careful carrying it so as not to squirt yer wort. The dimples take some extra care cleaning. I have one that is delaminating in one area. All that said, I like it better than alternatives for portable fermenters... the new lid seals well but also removes easily (just dry the silicone ring & inner side of fermenter top with a paper towel)l; I can watch fermentation; punted bottom; easy to go top-harvesting yeast ranching. Glass is heavy for me to carry up and down stairs. The big mouth is handy for dry hopping and cleaning. Competitor (FerMonster) is even flimisier when full. I'm getting out of buckets and going with more Big Mouths.
September 6, 2017
Great carboy! Terrible lid.
Love it! Good size, big enough to reach inside, makes for easy cleaning, not heavy and is easily customizable. Way better than the bucket I used the first time I brewed. Only downside is that the lids (single or dual) don't stay on once fermentation starts. I read all the reviews and was prepared for this though. I was able to duct tape it down and it stayed, but there's gotta be a better way. New lid design is needed.
August 15, 2017
6 months ago
the lid is terrible
Well, I wish I had read the reviews before buying a 4 pack of these fermentors. 2nd day into fermenting an all grain swig of sunshine the lid popped off...who knows how long it was off. can pretty much guarantee this bath is ruined. If this is such a big problem why are you still selling them. UNSATISFACTORY!
July 17, 2017
Wide mouth is awesome, lid sucks!
Great light weight vessel with great head space. I like that I can see my fermentation process take place. The only thing I would say is negative about this is the lid. I would prefer the screw on lid because the plug style that comes with it doesn't hold well. The lid would pop up but not off causing the air to leak out the sides versus the airlock. I ended up taping the lid shut so that my only exit point is the airlock.
May 26, 2017
8 months ago
Used to be great; lid is useless and there's no substitute
I bought these carboys back when they came with the screw-on lids. I assumed these did too. Nope, they come with the universal lid which SHOULD BE AVOIDED AT ALL COST!!! The new universal lids do not stay on and are highly prone to popping off. There isn't a screw-on option or any other substitute for this product, so it's essentially a large-mouth carboy that doesn't come with a lid (because the lid doesn't stay on). If you are looking to add onto your existing plastic large-mouth carboy collection or if you're interested in trying one out, this is DEFINITELY A PRODUCT TO AVOID because of the lids and a lack of a substitute. I will be buying different carboys from now on.
May 9, 2017
9 months ago
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 17 questions Browse 17 questions and 35 answers
Are these Bubbler Plastic Fermenters BPA free?
A shopper on Nov 29, 2016
BEST ANSWER: I looked on my bubbler, as well as one that is still in a box, & couldn't find anything that says it is or it isn't. Sorry.
Is there a solution for the universal lid popping out during active fermentation? Would the normal screw on lid work better during active fermentation?
joseph n on Jun 26, 2016
BEST ANSWER: flip the gasket upside down. I brewed my first batch and had the same problem couldn't get a proper seal. saw on a forum if you flip the gasket upside down if seals fine. fermenting a bourbon barrel porter right now no problems with seal.
How do these hold up to cold crashing? Will they collapse or crack?
A N on Feb 26, 2016
BEST ANSWER: Cold crashing an IPA in one of these for a week at 38F, no issues at all yet
Does the Big Mout Bubbler have volume markings?
A shopper on Jun 20, 2017
Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor
Big Mouth Bubbler® - 6.5 Gallon Plastic Fermentor
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Siphonless Big Mouth Bubbler® - Ported 5 Gallon Plastic Fermentor
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Big Mouth Bubbler® - 5 Gallon Plastic Fermentor
Big Mouth Bubbler® - 5 Gallon Plastic Fermentor
BEST ANSWER: Yes, the Big Mouth Bubbler Plastic does have indentations as markings but does not have numbers 1 - 5 or .
You have to count them to determine at what level you are at.
Might be dumb question but this product comes with a lid yes?
B R on Dec 27, 2015
BEST ANSWER: Yes. Comes with a lid and threaded collar. If you haven't yet, you'll probably also want to pick up a drilled stopper to accommodate an air lock
I’ve broken two glass carboys in my day. How does this one get transported? Do I simply pick it up and lug it to my fermenting closet or do the make a carrying handle?
A shopper on Oct 29, 2017
BEST ANSWER: I pick them up by the collar that holds the lid on. Or tilt and get a hand underneath. They are much easier to move than glass carboy
what is the hottest this carboy can get before damage occurs?
T H on Aug 2, 2016
BEST ANSWER: Temperatures over 140 F will damage these plastic fermenters, so care must be taken when cleaning them or using them. We do not recommend pouring hot wort into them in any situation. - Mike W, Northern Brewer
Does this come with the universal lid or the standard lid? Also, are people having issues with universal lid popping off on the plastic big mouths like people have observed happening in the glass versions?
J A on Jun 26, 2016

Thank you for your question. This does indeed come with the new universal lid. Anytime you have very active fermentation you can run the chance of the lid and/or bung popping out.

Will the Brew Hauler work with these? I know there is a special harness for the BMBs, but I already have several Brew Haulers and would like to avoid buying yet another carry strap... Thanks!
J K on Apr 22, 2016
BEST ANSWER: The brew hauler will work on a BMB plastic. Not as well, but well enough to avoid getting a new strap! Cheers!
I never seem to get any bubbles from my airlocks. They are always seated tighly yet still no bubbles. Must be a leak in the lid. Is there supposed to be a gasket?
R E on Jan 14, 2016
BEST ANSWER: No gasket - I've personally never had an issue with there being no bubbles. My question would be if you checked the seal before putting any wort in? I did this by putting the lid on tight, putting my blowoff hose in and trying to suck air in...I was not successful! That told me certainly enough that it had a good seal. Hope this helps.
I was told not to use plastic when brewing mead due to bacteria, is this a legit problem?
P F on Dec 23, 2015
BEST ANSWER: Plastic fermentors are suitable for any fermentation including mead. Bacteria is not a problem provided that you clean and sanitize properly and do not scratch the plastic.
A shopper on Feb 5, 2017
BEST ANSWER: It helps to settle the yeast around the perimiter of the fermenter. I will try to siphon off the top of the bubble to keep yeast to a minimum
I have a standard NB blow off tube for a standard 6.5 gallon glass Carboy. Will this fit into the opening of the lid provided?
F R on Sep 21, 2016
BEST ANSWER: Yes, the whole dimensions are the same size in this lid as they are for the standard carboys.
I have read leaving beer in secondary for a long time in plastic can be harmful. is that still the case or have these new products gotten better?
N A on Mar 24, 2016
BEST ANSWER: The main reason to use glass for secondary is that plastic vessels don't always seal quite as well as glass, and oxygen can leak in and cause staling. Of course this isn't a problem during primary fermentation, but if you're going to do a secondary, especially a long one, glass is still usually better. Using plastic raises the risk a little, but it doesn't necessarily ruin it. That said, I've used plastic for a secondary before, and I've never experienced anything negative myself.
I have the big mouth bubbler with the dual port lid and a blow off tube. I really like the whole system but I have not used the blow off tube yet because it does not give a snug fit into the dual port lid. What is the trick to get a good fit, I just don't feel comfortable with the way it fits now.
Noel J on Nov 1, 2015
BEST ANSWER: Thanks for contacting us. Tricks include having the right angle for the tube so that it is pulled by the free end to make a seal at an angle- that is how most common set ups allow for it to seal. You can also try using some teflon tape of some sort to help get it snug. The tubing will vary based on kinks temperatures and many factors. You can try putting one end in hot water and then stretching the tubing over the lid port to stretch it and then it may fit more snugly inside the tube. Since it is there to allow yeas to leave as needed and fermentation is pushing everything away nothing can get in anyway and the tubing just prevents big messes and makes cleaning up easier.
Where can I get a threaded lit for this?
A shopper on Jan 1, 2018
Is there a threaded lid for this? Not the included blue push in cap, but an actual screw on style cap? If not, can you tell me what size cap (like a mayo jar lid style) to get that fits the threads on the outside of the bubbler?
A shopper on Dec 27, 2017

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