Pilsner Pressure Ferment and at Lager Temps?

[Bassman2003]

I think they work that way. Meaning you can get both gases out based on the settings. A couple of guys on the 'other forum' have them from Ebay finds. Quite useful for affordable inert gas creation once you clear the initial expenditure.

 

[mac_1103]

Interesting. Wouldn't have guessed that the oxygen removal was good enough.

 

[VTMongoose]

My only negative observation from pressure vs ambient/atmospheric fermenting is that it does slow down fermentation slightly. Which can be easily fixed by simply pitching more yeast. I don't recommend pressure fermenting farty strains like Augustiner or K-97 but all the rest I've tried (BRY-97, US-05, Notty, S-04, S-189, 34/70, Diamond) have been clean as a whistle. Recently around 50% of my beers have been pressure fermented.

 

[Bassman2003]

Interesting. Wouldn't have guessed that the oxygen removal was good enough.

Not sure what you mean.

 

[mac_1103]

Not sure what you mean.

Just wondering whether all of the oxygen is removed. The device doesn't have to be anywhere near 100% efficient at capturing oxygen from ambient air in order to provide highly concentrated oxygen for breathing. But if you're going to use it "in reverse" for beer, then you do want it to be pretty close to 100% efficient.

 

[Bassman2003]

I see. I think it is very pure. BTW, the machine is quite large and complex, so it probably is more capable than maybe one of those portable breathing machines.

 

[Deadalus]

The CO2 is the stressor and the cold invites more CO2 into the wort. Cold alone does not stress yeast, it just slows them down.

I'm not disagreeing with much of what you have said but your use of stress and stressor here and above suggest a more conservative idea of what a stressor is. Placing an organism outside its optimal temperature range is a stressor for organisms leading to a stress response. I think you are using the terms to imply there is some noticeable detrimental effect in the beer. Excessive cold is a yeast stressor as too much will freeze it dead.

 

[Bassman2003]

In the context of a lager thread, cold (50F) fermentation temps are not a stressor of yeast. Especially lager yeast. CO2 is toxic to yeast. Meaning much more stress induced than cold temperatures. Yes, freezing temperatures will kill yeast too, but that is not really in context to this conversation.

To clarify, I am speaking in terms of the yeast, not the beer. Now the result of yeast stress does show up in the beer which is a large benefit of pressure fermentation. When yeast are stressed in different ways they product different things, flavors or substances. High pressure tends to create a little thicker mouthfeel or body to beers along with suppressing esters.

But it is not the "pressure" so to speak that influences the yeast but the level of CO2. This is where temperature comes into play along with gas laws. Higher temp means less dissolved CO2 compared to lower temps. So a 2 bar 70F ale fermentation would fewer volumes of CO2 in the wort than a 2 bar 50F lager fermentation. By accounts the yeast seem to be less affected by pressure compared to the toxicity of carbon dioxide.

Pro breweries have a lot of pressure in their large vessels but it is not derived from CO2. Just trying to point out that the real thing to focus on is what volume of CO2 one is fermenting at. Which took me a lot of others to realize.

 

[Deadalus]

In the context of a lager thread, cold (50F) fermentation temps are not a stressor of yeast. Especially lager yeast. CO2 is toxic to yeast. Meaning much more stress induced than cold temperatures. Yes, freezing temperatures will kill yeast too, but that is not really in context to this conversation.

To clarify, I am speaking in terms of the yeast, not the beer. Now the result of yeast stress does show up in the beer which is a large benefit of pressure fermentation. When yeast are stressed in different ways they product different things, flavors or substances. High pressure tends to create a little thicker mouthfeel or body to beers along with suppressing esters.

But it is not the "pressure" so to speak that influences the yeast but the level of CO2. This is where temperature comes into play along with gas laws. Higher temp means less dissolved CO2 compared to lower temps. So a 2 bar 70F ale fermentation would fewer volumes of CO2 in the wort than a 2 bar 50F lager fermentation. By accounts the yeast seem to be less affected by pressure compared to the toxicity of carbon dioxide.

Pro breweries have a lot of pressure in their large vessels but it is not derived from CO2. Just trying to point out that the real thing to focus on is what volume of CO2 one is fermenting at. Which took me a lot of others to realize.

No, while the conversation mentions 10C, subsequently people were discussing temperature more relatively, that is "colder". 50F was not a strict bound for the thread. Some lager yeasts are a bit slow as well at 50F anyway.

And even you said "You just need more yeast to pull of a cold pressure ferment." One thing that means is the yeast needs a greater population to avoid being outcompeted or just dying off before using all the resources available (kinda like extinction). Needing more yeast can affect your wallet as well. It's good that you are clarifying and suggesting the more important stressor is CO2 concentration however colder temperature is a stressor too.

 

[Bassman2003]

This is kind of splitting hairs with the verbiage imho. Cold temperatures may slow yeast activity but they do not cause the yeast harm or to secrete substances. CO2 does. Cold being anything above freezing where the cells do not explode. But pitch enough yeast and a lager will finish in five days. I don't see yeast under stress in cold temperatures, just reacting to an environment.

But the whole thrust of discussing temperatures & pressure is to try to decouple pressure fermentation from high temperatures. The two are stuck together in the homebrew world for convenience. Lager without pressure at normal cold temps is great. Lager at high temps is less great while lager at cold temps + pressure is really great. I know people do everything but just speaking from an optimal point of view...

 

[Deadalus]

This is kind of splitting hairs with the verbiage imho. Cold temperatures may slow yeast activity but they do not cause the yeast harm or to secrete substances. CO2 does. Cold being anything above freezing where the cells do not explode. But pitch enough yeast and a lager will finish in five days. I don't see yeast under stress in cold temperatures, just reacting to an environment.

But the whole thrust of discussing temperatures & pressure is to try to decouple pressure fermentation from high temperatures. The two are stuck together in the homebrew world for convenience. Lager without pressure at normal cold temps is great. Lager at high temps is less great while lager at cold temps + pressure is really great. I know people do everything but just speaking from an optimal point of view...

I am not splitting hairs, I think your understanding and use of the term is incorrect. If cold is "slowing yeast activity" then it is affecting homeostasis. The yeast is already not reproducing at its optimal rate either. Starters are made at about 70F. If you put a plant in cold conditions and it does not fruit, it would be considered stressed. That you are not seeing affects to the organism that interfere with brewing from the cold does not mean the organism is not under stress. Simply understanding that the cold will take the yeast longer to finish is indicative of placing stress on the organism.

 

[Bassman2003]

So if we define cold fermentation as "stressed" fermentation, does that make it anything? - better, worse etc... Optimal beer is what we are (I am) after and fermenting lager yeast warmer might be easier on the cells themselves but not the original intent of making the best beer. I see the warm fermented lager beer as being "stressed"

 

[Deadalus]

So if we define cold fermentation as "stressed" fermentation, does that make it anything? - better, worse etc... Optimal beer is what we are (I am) after and fermenting lager yeast warmer might be easier on the cells themselves but not the original intent of making the best beer. I see the warm fermented lager beer as being "stressed"

There is no proposal on my part for new categories, I am simply suggesting using terminology appropriately and with understanding. Which the following was not, even with your caveat that this is a thread about lager yeast.

Cold is not a stressor for yeast. That was never said.

And you also said this,

To clarify, I am speaking in terms of the yeast, not the beer.

but now you are switching back to discussing "optimal" beer.

Colder temperatures are a stressor for lager yeast. That stress may or may not need to be accounted for when making beer using a given beer process but it most certainly helps to have that basic fact acknowledged properly.

 

[HighVoltageMan!]

If you manipulate the yeast’s environment to get the desired beer you want, who gives a $h1+ if the yeast is technically stressed?

I seriously doubt the yeast is substantially stressed unless the conditions are extreme in either pressure or temperature. Both low temperatures and higher pressure produces a greater amount of co2 in solution. In addition, the low temperatures, along with pressure produces conditions favorable to low esters and lower production of any alcohols outside of ethanol.

 

[Deadalus]

If you manipulate the yeast’s environment to get the desired beer you want, who gives a $h1+ if the yeast is technically stressed?

I seriously doubt the yeast is substantially stressed unless the conditions are extreme in either pressure or temperature. Both low temperatures and higher pressure produces a greater amount of co2 in solution. In addition, the low temperatures, along with pressure produces conditions favorable to low esters and lower production of any alcohols outside of ethanol.

Because simply being aware that it is stressed can influence decisions regarding other parts of the fermentation process.

It's important to note that it is stressed to whatever degree when experimenting. Then one could appropriately account for any temperature effects, including possible interaction effects. You can't do that if temperature has been ruled out prematurely. And personal anecdotes and observations are fine, I don't have any comments against most of what was said. I only gave a gentle caution that temperature conditions were a stressor. Because it's true. Science and all right?

 

[HighVoltageMan!]

Because simply being aware that it is stressed can influence decisions regarding other parts of the fermentation process.

It's important to note that it is stressed to whatever degree when experimenting. Then one could appropriately account for any temperature effects, including possible interaction effects. You can't do that if temperature has been ruled out prematurely. And personal anecdotes and observations are fine, I don't have any comments against most of what was said. I only gave a gentle caution that temperature conditions were a stressor. Because it's true. Science and all right?

Brewers yeast is never in an "ideal" situation, by that definition it is typically "stressed" while ferment nearly any beer you could think of. If the yeast were kept in an ideal condition, we would pitch the yeast into 1.030 wort with a pH of 4.7. We would also aerate the yeast until it was nearly complete with it's food supply, we would also expel all co2. That certainly will not make very good beer, but the yeast will thrive in those conditions.

By stressed it would be assumed, at least by me, that harm was coming to the yeast. Colder temperatures (above freezing) do not stress yeast as so much as change it's behavior (it's often stored at temperatures near freezing to keep it healthy and fresh) and pressures up to 2 atmospheres do little to harm yeasts other than to slow it's reproduction, among other things. They slow and change their metabolisms desirable to a type of beer we want to produce. We can also ferment warm in shallow, wide vessels to expel the co2. Much better for yeast and Belgian beers (unless the alcohol gets too high, then the yeast is actually harmed), bad for German lagers.

Fermenting beer has, in a round about way, selectively bred many yeasts that are remarkably robust. Brewers purposely "stress" yeast to produce a product that has the characteristics they're looking for.

Sorry for the rant.

 

[Deadalus]

Brewers yeast is never in an "ideal" situation, by that definition it is typically "stressed" while ferment nearly any beer you could think of. If the yeast were kept in an ideal condition, we would pitch the yeast into 1.030 wort with a pH of 4.7. We would also aerate the yeast until it was nearly complete with it's food supply, we would also expel all co2. That certainly will not make very good beer, but the yeast will thrive in those conditions.

By stressed it would be assumed, at least by me, that harm was coming to the yeast. Colder temperatures (above freezing) do not stress yeast as so much as change it's behavior (it's often stored at temperatures near freezing to keep it healthy and fresh) and pressures up to 2 atmospheres do little to harm yeasts other than to slow it's reproduction, among other things. They slow and change their metabolisms desirable to a type of beer we want to produce. We can also ferment warm in shallow, wide vessels to expel the co2. Much better for yeast and Belgian beers (unless the alcohol gets too high, then the yeast is actually harmed), bad for German lagers.

Fermenting beer has, in a round about way, selectively bred many yeasts that are remarkably robust. Brewers purposely "stress" yeast to produce a product that has the characteristics they're looking for.

Sorry for the rant.

I never said the yeast should be kept in ""ideal" environment. You are touching on ideas between fundamental and realized niches but that is getting away from the definition of stress.

Thinking of stress as "harm" I believe is the issue some are having here. It's why I mentioned homeostasis earlier. I just said one should be aware that cold is a stressor, cold is taxing the yeast to some degree. This is clearly evident by reduced activity on the part of the yeast as the temperature decreases.

In biology, stress is defined as a state of physiological and psychological strain or tension caused by external or internal factors that disrupt homeostasis (balance) in an organism.

I fully acknowlege that the defininition may broadly label many factors as stressors, but that's why I noted the usage as being incorrect.
Temperature is a very common stressor for biological organisms.