Backpressure causing stuck ferment?

[Drunkula]

I saw an owner of a company (not calling anyone out) say that overfilling airlocks can cause too much backpressure that can lead to a stuck ferment. Now because of all the brewing under pressure with faancy valves and all that I thought this sounded like it might not be true. Anybody heard of this or do you think it's a load of tripe?

 

[peebee]

Yeah, the dreaded "Saison stall" (when using the Dupont yeast) gets attributed to this "airlock back-pressure". This "owner of a company" seems to be taking that suggestion out of context: Or, to give my opinion (as someone who's used fancy valves and brewing under pressure) it's a load of (I'd prefer to use something a bit more graphical than "tripe").

 

[dan125]

Agreed - I've fermented ale strains under pressure without problems. On a commercial scale there must be much higher pressure on the yeast at the bottom of big FVs than we could ever achieve with an airlock at home.

 

[Slid]

Well, until I learn that bottom fermenting yeasts are used commercially in no deeper than 6 inch high fermentation vessels, I will have to side with the view that it sounds like a bunch of sludge to me.

 

[Drunkula]

Thanks everyone. I've got 2 x 30 bottles of wine kit stuff on now and wondered if I should dump some of the airlock water. Not happening now.

 

[terrym]

The back pressure created by an airlock is normally about 4mmH2O which is naff all. If you overfill the back pressure is probably twice that i.e naff all.

 

[sevorg]

To put this in perspective, commonly observed atmospheric pressure varies between 970 and 1040 mb a variation of 70mb which equates to 700mm of H2O so complete and utter tripe!

 

[Cwrw666]

Only real problem with overfilling an airlock is that when you pull the bung out of the demijohn or whatever you risk sucking the airlock fluid back into the DJ.