Glass or Plastic. Which Big Mouth Bubbler is for you?

Since writing my last article I have had the pleasure of using the Plastic BMB a few times. After a lot of thought on comparing the glass versus plastic I think I have a good idea on which I prefer, why I feel this way, and the pros and cons of both.

First, I will start off with the glass BMB.

Glass Pros:

• Zero air permeation, just like any glass carboy
• No chance of carryover taste from batch to batch
• Nice harness makes moving and pouring a lot easier than traditional brew haulers
• Can last a life time with proper care

Glass Cons:

• Fragile
• Defects in the glass
• Lid cannot accommodate any sort of siphon or thief
• Difficult to rest siphon hands free
• Heavier than plastic, 6.5 gallon weighs 16lbs empty! That's about equal to carrying 2 extra gallons of beer.
• Potential need for replacement gaskets. Although rare it can still be a potential recurring cost.

As you can see there are more cons than pros in my eyes. I do love to use glass, but I have some concerns with these fermentors in particular. The imperfections in the glass concern me, I constantly find myself checking for stress cracks around the defects.

As a primary I see no need to go with the glass version over plastic. Keeping oxygen out at this stage is very easy, and air permeation isn't really an issue. The lack of ability to siphon with the lid on is really off putting after using the plastic BMBs. Not having a punted bottom for the siphon to rest on doesn't help either. You may not notice a difference having never had these features, but I am having a hard time going back.

However, as a secondary, the glass version still proves invaluable. I make a lot of beers that benefit from long term aging. I know that the air permeation of PET plastic is supposed to be very low, but it isn't non existent. Either way, I trust glass, or a keg, for long term aging.

Also, something to consider is the size of both.

These are the 6.5 gallon sizes. As you can see, the plastic version is noticeably taller than it's glass counterpart. Plastic coming in at 23 inches and glass coming in at 17.5 inches. The 5 gallon versions have similar differences. Plastic coming in at 22 inches and the glass coming in at 16 inches. All of these measurements do not include airlocks of course. Something to consider along with your fermentation chamber size before you purchase either one. That being said the 10 inch footprint of the plastic is significantly smaller than the glass at almost 18 inches.

Now on to plastic. Not being a fan of buckets, I never thought I would like plastic so much.

Plastic Pros:

• Super light (4lbs for the 6.5 gallon)
• Dual port lid (optional)
• Punted bottom
• Volume markings
• Much easier racking

Plastic Cons:

• Same flexing problem as other plastic carboys
• Lid ring seems to work itself off unless tightened down very hard
• Texture on the anti-flex ribs like to hold onto trub when cleaning
• Air permeation

Biased or not, I definitely feel there are more pros than cons to the plastic version. As long as you aren't doing any long term aging, you can't go wrong with the plastic version of the Big Mouths.

The biggest advantage in my opinion is a combination of the dual port lid and the punted bottom. I'll start with the former.

The dual port lid is amazing. I like taking samples as my beer ferments, and while it's conditioning. I have all but permanently stored the single port lid. Being able to sample and rack without removing the lid is easily my favorite feature. No siphon clamp needed. That in combination with the punted bottom really takes the ease of use to a whole other level.

The punted bottom is also amazing. I always attach my tubing to the racking cane after I put the siphon into the wort. So, I will put the auto siphon together, and find the punted bottom and just let the siphon rest in that indent, while I attach the tubing and proceed to siphon. Can't get much easier.

As you can see, there isn't much left after siphoning. I got this much out of it and did not move the siphon an inch. However I do see a potential issue with this, maybe with low hop lower gravity beers. I had plenty of trub in this beer, so I only lost about 1/8 of a gallon. If there were less trub I could see you potentially losing up to ¼ of a gallon.

All that being said, I still would refrain from aging anything long term in these. PET plastic is supposedly still air permeable. Although it may be to a lesser degree, I still wouldn't risk it on a brew I intend to age in the fermentor.

I don't know if I would say one is better than the other. I prefer each for specific purposes. However, I will help you make the best decision for your specific needs or situation.

Reasons to consider plastic

• Much lighter, at only 4lbs for the 6.5 gallon
• Smaller footprint, if that is valuable in your fermentation setup
• Dual ported lid makes just about everything easier
• Punted bottom in conjunction with the lid is amazing
• Virtually indestructible

Reasons to consider glass

• Does not permeate air
• Preferred material for long term aging
• Short in stature, if that is valuable in your fermentation setup
• Lasts a lifetime

Taking all this into consideration, I hope I have helped you decide which is best for you. I have used both, and would say without a doubt both are great buys. The ability to reach your arm inside the carboy and clean is revolutionary. I love them both and wouldn't turn either down. I got all of mine from Northern Brewer, they have always been great to me and the flat rate shipping is awesome.

Thanks for reading. Cheers!