Wide mouth plastic carboy?

I have one of the 6.5 gallon plastic "big mouth bubblers". I fermented my favorite ipa so far in it and it sealed up just fine. Very easy to clean not very easy to grip when full though. Two thumbs up from me!

 

Like this one?

 

http://www.northernbrewer.com/shop/brewing/brewing-equipment/fermenting-equipment/big-mouth-bubbler

Most likely

 

Id be wary OP...Bought a 6g and a 5g and had nothing but problems! The lid sits atop the carboy, no seal and is a twist top (plastic thread on plastic thread) with no gasket. Fashioned my own lid seal out of food grade rubber material and tefloned the threads...used em once and never again! Def not ideal for ageing

 

Plastic is still plastic, and on it's best day, still isn't glass... JM2c
The wider the mouth the bigger the challenge to seal up..

 

If you want a wide mouth carboy with a lid that actually seals, you get a Speidel.

 

I've had great luck cleaning carboys with an overnight soak in Oxy Clean. To finish off stubborn residue, you can clean with terry cloth. Cut the cloth into strips. Take a strip and tie an overhand knot in the middle. Put this in the carboy with around 1/2 gal of water or Oxy Clean. Put your hand over the mouth and turn the carboy sideways. Now swirl the water and the terry cloth around the carboy in a circular motion.

Edit: After the soak, this process usually only takes a few minutes.

 

So the theory is oxygen is getting in there? Isn't there a CO2 blanket created from the active fermentation that protects the beer from this?

I bought one and have used it a couple times but both have been Brett beers so maybe Brett's anti-oxidative properties are keeping me from noticing this flaw. But I will say the airlock has been active both times, just like a glass carboy fermentation.

 

CO2 is a gas, not a solid, and does not prevent oxygen from reaching the beer. I think that may the biggest, most persistent homebrew myth.

 

I agree there is some mythology associated with this topic.

But there are circumstances when a CO2 blanket can be effective in keeping O2 from the beer. It's all about time scales and whether or not convection (macroscopic mixing) is important.

If convection is absent, then diffusion is the only means of O2 transport through a layer of CO2. In this case a layer of several inches can be an effective barrier for a something like tens of minutes.* This would apply, for example, when transferring wort from a fermenter to a keg. This is why the CO2 in a purged keg is an excellent idea; the CO2 is a good shield during the transfer process.

On very long time scales O2 will, of course, diffuse through CO2, as it will also do a solid. The rate of diffusion (per unit length) through a solid is much slower than through a gas; the rate, of course, depends upon the material. The reason glass is preferred over (at least some) plastics for long term aging of beer is because of their relative diffusion constants.

Cheers!

*An estimate based on past calculations, which I do not have at hand.

 

I almost bought into this big mouth carboy thing until I saw this video.

I use PBW with hot tap water and let the carboy soak either a few hours or overnight(depending on how busy/lazy I am). Then pour out most of the PBW, drop in a washcloth and spin away. Have yet to meet any dried krausen that I could not remove.

 

Agreed. I was referring to beer sitting in a fermenter.

 

right but how will this be different in a big mouth bubbler with an airlock than a standard carboy mouth fitted with bung or cap?

 

The O2 diffusion through CO2 phenomenon will not be different. But the less sealed fermenter will let in more O2 (i.e. let it in faster) than the better sealed fermenter, so there will be more O2 to diffuse through the CO2. So the diffusion (and oxidation of the beer) will be greater/faster.

ETA: I haven't used a big mouth bubbler, so I can't say first hand whether or not they are leakier than a typical carboy setup.

 

It definitely will. But when you say "given enough time," it's not a matter of "no O2 until some amount of time has passed, then some O2." It's that the material is permeable to O2. So diffusion starts right away. It's just that the longer it goes, the more O2 gets in.

 

Do you have some information (a technical paper/article) to back up the figure of "4 weeks"?

Cheers!