Ever do a lager, under pressure and at ale temps?

[MrBJones]

If so, how did it turn out? Would you do it again?

 

[Jtvann]

I was planning to yesterday and found that I was 5 lbs short on grain in my order. I will next weekend. I’ve read to go 15 psi from the start at about 65 degrees. That was my plan unless someone else chirps in with another process.

Using WLP820

 

[MrBJones]

I've only read about it, so take this with a boulder of salt... But in some of the online articles it's said that pressure impedes yeast growth. For that reason some recommend that you start at ambient pressure, and at normal temperature, with the system sealed. Then, after it pressures up naturally, add co2 as needed and let the temperature come up.

 

[Jtvann]

I planned to seal it from the start and let pressure build naturally. I hear that all yeast enjoy the higher temps (relatively) but that they have a tendency to throw more esters depending on type. More so early on. I don’t think it will throw enough early on to bother that much building up.

Correct me if I’m wrong on this. When O2 is present, yeast multiply. After it’s gone, yeast doesn’t continue to multiply throughout the entire process. After O2 is gone, CO2 builds. That’s been my assumption, but if I’m assuming right, yeast should be done multiplying by the time pressure is a factor.

 

[crazyjake19]

I was planning to yesterday and found that I was 5 lbs short on grain in my order. I will next weekend. I’ve read to go 15 psi from the start at about 65 degrees. That was my plan unless someone else chirps in with another process.

Using WLP820

I ferment lagers under pressure often (Marzen and American Light Lager most often), and that is the method I use. Always at basement temperature which for me varies from 62-68F, and have done both initially pressurizing the keg to ~14psi right after yeast pitch as well as letting pressure build naturally, and have noticed no difference in yeast performance or final taste. With either method, I attach a spunding valve set to around 15psi and days 2-4 I have noticed quite a bit of excess pressure being vented to keep the fermenter at or below 15psi.

That being said, I've only used White Labs WLP925 High Pressure Lager yeast for pressurized ferments and have never used WLP820, so I cannot comment on what results you'll have, thought I don't expect it to be negative.

 

[Otis11]

I am no expert but here's my story.

Last February I made the switch from fermenting in glass carboys to corny kegs. I brew in the garage and ferment in the basement so carrying loaded glass carboys down a flight of stairs was just a ticking timebomb. Also, I have always wanted to do lager but didn't have the refrigeration or patience. Then, I read about pressure fermenting.

When the wort is ready I put it in a clean/sanitized fermenter, a drop or three of fermcap, put in a packet of 34/70.

Set my valve at around 12 to 15psi and let it go for about a week to 10 days. Fermenting is completed in my basement where temps are around 70F year round.

My fermenting kegs have a floating dip tube but my serving keg does not. Really no reason why but I like the regular dip tube in my serving keg since the floating misses a few ounces at the end of the keg. This is good for the primary but not much trub gets transferred to the serving keg so I haven't invested in a floating dip tube for my primary.

Can take a gravity reading with a picnic tap when needed.

Once finished I do a closed transfer to my purged serving keg. Eliminating oxygen is key for me here. Also, make sure your transfer psi is at or lower then what you fermented at or else you will over carb. Can add gelatin with a large syringe via the in post if wanted. Three or five days of cold crash and I'm drinking.

There have been numerous discussions about if this is a true lager or not. I can go either way with that argument but I do know my beers are quite tasty to me.

I use 34/70 or MJ76 with great results.

To your question, "Would I do it again?" I only wish I had started earlier. Safer, no oxygen, lager at ale temps and very quick turnaround.

 

[Vale71]

Correct me if I’m wrong on this. When O2 is present, yeast multiply. After it’s gone, yeast doesn’t continue to multiply throughout the entire process. After O2 is gone, CO2 builds. That’s been my assumption, but if I’m assuming right, yeast should be done multiplying by the time pressure is a factor.

I'm afraid you're mostly wrong (and I'm been rather generous too ).

1 - Yeast will multiply even when there is no longer dissolved O2, both because yeast can store O2 for later use (up to a point) and don't need to use it right away as well as because yeast don't really need O2 to multiply but just to build sterol reserves. Some of those reserves do get passed on to daughter cells which can then multiply even if all dissolved O2 has been exhausted. The downside of this is that subsequent generations will be less and less vital.

2 - Yeast will carry out anaerobic fermentation even in the presence of abundant O2 at least at sugar levels as high as you'll find in normal wort. This means that there is CO2 production from the very start or more exactly once the lag phase is over. The lag phase is the only phase were yeast actually hardly produce anything (hence the name).

What this means in practice is that if you were to set the spunding valve to target pressure you'd start to see pressure buildup as soon as the lag phase is over. In commercial operations however this is still considered inadequate and the fermenter is sealed at a starting pressure of around 0.5 bar. Inoculation rates are also much higher than standard and oxygenation is somewhat reduced. Exact parameters vary from operation to operation and are of course a well-guarded trade secret.

 

[MrBJones]

Are there certain styles that are better suited for this? And, in particular, how would a doppelbock end up?

 

[Bilsch]

Trying to replicate the hydrostatic pressure in a large commercial cylindroconical fermenters at the homebrew scale by using total or top pressure is not going to be at all similar. In a large brewery the yeast cell will only see the highest pressure when it is near the bottom of the tank and conversely almost no pressure near the top. Beer in these large fermenters wells up and down on currents caused by rising CO2 bubbles and therefore yeast are continually moving through different pressure zones.

 

[dmtaylor]

I've started making lagers at room temperature using S-189 and been real happy with them... without pressurization. I think the pressure thing might not be a necessity.

 

[Bilsch]

I've started making lagers at room temperature using S-189 and been real happy with them... without pressurization. I think the pressure thing might not be a necessity.

It probably isn't required, especially for those who like their lagers to taste like ales.

 

[dmtaylor]

I *dare* any fraidy-cats to use S-189 at room temperature.

 

[Gusso]

I never did lagers in my years of Homebrewing until getting the SPUNDit in the last year. I now regularly do lagers at room temp. I crank up the psi to 30 on the SPUNDit and let it rip on one pack of 34/70 (the only lager yeast I've used to date). So far, so good.

 

[MrBJones]

I never did lagers in my years of Homebrewing until getting the SPUNDit in the last year. I now regularly do lagers at room temp. I crank up the psi to 30 on the SPUNDit and let it rip on one pack of 34/70 (the only lager yeast I've used to date). So far, so good.

What type lagers did you brew that way?