High-density polyethylene tank fermentors

[bizybrewer]

I know there has been a lot of talk about medium density polyethylene being oxygen permeable, but I was wondering if anyone had experience with the high density types. http://www.tank-depot.com/productdetails.aspx?part=SII-18545-1.9 is double the price of the medium density, but still a lot less than a SS type.

 

[broadbill]

Just a thought here...it sounds like you've researched this topic a bit so I'll ask: Have you actually come across any definitive accounts from brewers who have had oxidized beer coming out of either medium- or high-density polyethylene vessels, or is it all just hypothetical?

The reason I ask is that the distance between hypothetical and empirical can be fairly big. Many of us have brewing processes that are hypothetically bad for our beer, but empirically speaking, we don't have any problems.

For example, hypothetically I should not be fermenting my beers in ale pails for fear of oxidation. Empirically, however, I have seen no negative effects.

Another thing to consider...the scope in which you are working. Would a 5 year old Pale Ale fermented in plastic be oxidized? Its a possibility (again hypothetical). What is the chances that a pale ale makes it to its 5 year birthday in your house?....probably 0%. Chances are it won't see its 6 month birthday alot ot times.

Its all about rates, and kinetics and such....

 

[bizybrewer]

I don't know that anyone has done an empirical study on the matter, but based upon posts on here and around the web there seems to be a strong general consensus that after 2 weeks you should really transfer it out. Another thing i was thinking was that if it is oxygen permeable, why not paint it with some latex paint. i am pretty sure that isn't permeable.