Pressurized Fermentation in a Cornie

I’m running my first pressurized fermentation in a cornie keg, pitched yeast to 3gal of ESB last night and the keg was showing pressure this morning.  I roused the yeast and the pressure shot the the 7pai setppoint and began hissing out of the spunding valve.  I intend to run the pressure to 15psi in a day or two.  I didn’t shorten the dip tube so I will have to pull a little of the beer before counter-pressure transferring to a clean keg.

This is my second pressurized ferm, the first was done on a large conical (Brewhemoth).  It went quite well, typical FG, clean flavor and some free carbonation.  Plus its pretty darned fast from pitch to pint.

What sort of pressure relief do you have on the corny?

Its a homemade spunding valve, a plastic adjustable relief valve and a gauge all piped onto a gas-in ball lock QD.  I have a couple different relief valves, this one came from McMaster Carr and it goes 0-30psi.  My other one (Grainger) goes from 0-100psi.  I’ve seen one that is already put together that goes for $25, it only works between 0-15psi but that is the range that the yeast thrive in.  You’d still have to carbonate some with a tank, although I do that anyway.  Here’s a link to that unit:

Here’s a pic of my first spunding valve.  I think its post #524.  Sorry for linking to another forum but they host pics.  This one cost the better part of $100 to put together.  I did get the more expensive glycol-filled gauge since they are resistant to rusting.  The Grainger relief valve is cheaper and it has some marks so you can have some idea of where your pressure is at even before you get pressure and see on the gauge.  When I get that one plumbed up I’ll be giving it a try.

This is a new one on me…very interesting. First question: Why? Why ferment under pressure?

Why not?  hehe

Ok there are a few reasons, one you can ferment at a slightly warmer temp and it can be finished a little faster.  It mimics the pressures seen by yeast in a commercial fermentor.  Also, you get free carbonation while you’re at it.  The residual pressure can also be used to push the beer to the serving keg.  YOu can even hook said serving keg up in advance and pre-purge it with your CO2.

Cranked the relief valve tonight, then roused the yeast and got 15psi in short order.  Seems like the yeast is working well so far, will continue to rouse daily until I hear no gas escaping.

So, what bout the yeast cake in the bottom? You just transfer out to another keg and it stays behind? Or most of it?

There is a lager yeast that can ferment at 65F while under pressure and give a good lager character. Have you tried that one?

No, I’d heard about the ability to ferment clean lagers at higher temps but I didn’t want to push the envelope too much on this first go-around.  I probably should have, the house is staying fairly cool right now.

Oscar, the cake will settle in the bottom and I’ll rack out and let some of the yeast transfer too.  If this goes reasonably well I’ll probably cut the dip tube off so I’m not transferring yeast cake next time.

Check it out: http://www.whitelabs.com/beer/strains_wlp925.html

Looks very interesting, I’m always whining about how long lagers take.

I have had problems serving (cornie) keg conditioned beers.
The pin lock gets yeast in it and the beer pours slow and foamy. You might try tilting the keg away from the dip tube next time you rouse so the cake settles away from the dip tube.

Good idea.  I want to save the yeast anyway.  The WLP002 seems to drop like a stone so it ought to be possible to get most of the beer out without sucking a significant amount of cake.

A local brewpub uses that for their lagers, to speed up turn around time.  Sometimes they even rush that one too much.  You still need a few weeks lagering, if I am remembering what White labs says.

Yes they do talk about lagering and I can live with that.  They also say it produces sulfur early on and I’d worry that it wouldn’t gas out under pressure but it certainly seems like they are describing a fermentation that is under pressure the whole time.  I’ll pick some of this stuff up just for fun.  I’ve been making a decent helles with WLP830 so I have something to compare against.

Well my first cornie pressurized fermentation is done and things went very well.  Got very good attenuation (75% on a 1.052 brew) in five days.  Really things have been quiet as far as CO2 evolution since day 3.  I’m going to harvest yeast and then transfer to a serving keg.  I intend to employ this method on a routine basis from now on.