Adding airlock pressure to retain esters?

[kef300]

Was having a chat with a brew master at a local brewery. Mind you, he is over 60, studied the craft in Germany and is very "old school".

He said that airlocks should always be set at a regulated pressure (say 15 psi) as letting gas freely leave the vessel leads to esters and characteristic aromas escaping the beer. We were talking about a weisbier at that moment.

I had never heard or read about that concept. Were it to be true, homebrew airlocks would not be ideal for certain styles as the lack of a pressure lock would mean that a lot of the aromas could be lost.

Have any of you guys ever heard of this? Mind you, this is a guy that does not believe in using homebrew equipment as the lack of control is not the "proper way to make beer", so I'm a bit skeptical. I just think I would have read about it by now.

 

[Awesome-X]

Yes, you can do this at home by fermenting in a keg and using/building a Spunding valve.

http://www.homebrewfinds.com/2011/02/build-spunding-valve.html

http://byo.com/color/item/397-build-your-own-spunding-valve-to-carbonate-in-the-keg

Capping fermenters near the end of fermentation as a means to naturally carbonate is one of it's goals. I'm a bit hazy on the history but I believe it is "old school" as you say and lots of German breweries used this method. I was under the impression that, rather than using this to stop aromas from leaving the fermenter (which makes no sense, they will still leave once the pressure surpasses your 10-15psi you have it set at), that yeast is actually supposed to produce a completely different ester profile if fermented under pressure, which may or may not be more desirable.