Rousing up sleepy yeast with a Portable Co2 Charger

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dlester

dlester

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I was looking for a way to rouse up my yeast in a conical fermenter. I thought of hooking up my C02 system, but I didn't want to unhook it from my system and thought it might be possible that wort might fall back into the line.

The solution for me was a Cornelius Keg Portable CO2 Charger. I had to find a 1/2" to 1/8", which wasn't easy. I hooked it all up and shazzam, it worked!

If you like the idea, but don't have a conical fermenter, I would suggest using a tube and create a connector to the Portable CO2 Charger. I haven't done this part, but if you have an idea, let's hear it.

A pic of my yeast rouser:


_dsc4597-56152.jpg
 
Why CO2 and not air? When I have a lagged fermentation I just pump some air into my blow off assembly - venting the excess off.
 
Would alcohol or co2 restrict the yeast? The window for oxygenation would be just the start of fermentation?
 
CO2 could potentially suffocate the yeast. Not sure why you'd add alcohol?

I'm assuming this is early on in the fermentation.
 
jcaudill said:
Why CO2 and not air? When I have a lagged fermentation I just pump some air into my blow off assembly - venting the excess off.
Click to expand...

O2 will oxygenate the beer, that will ruin it and make it taste like cardboard and make it dull. C02 will push the yeast back up the beer and wake it up.
 
jcaudill said:
CO2 could potentially suffocate the yeast. Not sure why you'd add alcohol?

I'm assuming this is early on in the fermentation.
Click to expand...

The yeast creates alcohol and CO2, which slows process. Aeration of yeast/wort would be first part of fermentation. I'm wondering what kind of timing window there is before cardboard effect.
 
Yes, but yeast crap CO2 not absorb it. That is why we have blow-off's. If it's early fermentation filtered air would be better as yeast will feed on the O2. If it's later in the process I'm not sure why you'd want to rouse anything.
 
Old_mil_guy said:
Would alcohol or co2 restrict the yeast? The window for oxygenation would be just the start of fermentation?
Click to expand...

C02 is a by-product of alcohol production. It isn't going to suffocate the yeast, and it isn't going to restrict the yeast's job at converting sugars to alcohol either.
 
jcaudill said:
Uhm - at what part of the process are we talking about here?
Click to expand...

Good question; moving the yeast around is not part of the regular process. But it is handy to know about in certain situations.

Lager yeast is a bottom feeder and will drop out of the beer when it is cold, getting lazy or dying from a high alcohol environment. Yeast will work in solution and from the bottom, but as more layers are added, the bottom yeast no longer have contact with the beer and stop working. Thus, rousting up the beer brings the lower layers back into contact with the beer. The exception would be the yeast that are dead, rousting them wouldn't help.

When fermenting lagers or Boch type beers, which is also a lager, your temperature will often be around 50F. The yeast can handle this type of temperature, but require a larger amount of yeast to accommodate those yeast that slow down and sometimes drop out of solution.

Your most ideal situation is to have a large enough yeast slurry that is healthy enough to handle cold and higher alcohol environments. There are yeast calculators on the web that will help you determine the most beneficial amount of yeast to use. In addition, a good amount of oxygen at the beginning of the fermentation process will strengthen the yeasts outer layer making the yeast less permeable to alcohol and therefore lasting much longer in a high alcohol environment.

In conclusion, rousting the yeast is a good way to move yeast at the bottom back up into the beer solution to hopefully get it back in production.
 
Old_mil_guy said:
The yeast creates alcohol and CO2, which slows process. Aeration of yeast/wort would be first part of fermentation. I'm wondering what kind of timing window there is before cardboard effect.
Click to expand...

Adding O2 at the beginning is part of the basic process taught in every home brewing book. It is also typically followed by "don't allow your beer to have contact air/O2 after that point." The O2 is absorbed by the yeast and from that point the O2 is typically depleted. I believe that the yeast's outer layer is no longer permeable and therefore doesn't absorb any additional O2. Therefore, any additional O2 added to the beer will sit in solution and make the beer stale.
 
dlester said:
Good question; moving the yeast around is not part of the regular process. But it is handy to know about in certain situations.

Lager yeast is a bottom feeder and will drop out of the beer when it is cold, getting lazy or dying from a high alcohol environment. Yeast will work in solution and from the bottom, but as more layers are added, the bottom yeast no longer have contact with the beer and stop working. Thus, rousting up the beer brings the lower layers back into contact with the beer. The exception would be the yeast that are dead, rousting them wouldn't help.

When fermenting lagers or Boch type beers, which is also a lager, your temperature will often be around 50F. The yeast can handle this type of temperature, but require a larger amount of yeast to accommodate those yeast that slow down and sometimes drop out of solution.

Your most ideal situation is to have a large enough yeast slurry that is healthy enough to handle cold and higher alcohol environments. There are yeast calculators on the web that will help you determine the most beneficial amount of yeast to use. In addition, a good amount of oxygen at the beginning of the fermentation process will strengthen the yeasts outer layer making the yeast less permeable to alcohol and therefore lasting much longer in a high alcohol environment.

In conclusion, rousting the yeast is a good way to move yeast at the bottom back up into the beer solution to hopefully get it back in production.
Click to expand...

This situation I am familiar with because it just happened to me. My festbier fermentation started out real sluggish. So what I did was take some highly filtered air and blow it into my blow-off and vent it through another valve I have. It only took about a minute to shake things up and literally within' minutes fermentation picked up.

The point I was trying to make about CO2 suffocation is true - but I had a brain fart. If you're still using your blow-off at this point then no problem - the CO2 you push in will eventually exit. I was thinking about spunding for some reason - the build-up of CO2 will make the yeast go dormant or extremely sluggish depending on the strain.
 
jcaudill said:
This situation I am familiar with because it just happened to me. My festbier fermentation started out real sluggish. So what I did was take some highly filtered air and blow it into my blow-off and vent it through another valve I have. It only took about a minute to shake things up and literally within' minutes fermentation picked up.

The point I was trying to make about CO2 suffocation is true - but I had a brain fart. If you're still using your blow-off at this point then no problem - the CO2 you push in will eventually exit. I was thinking about spunding for some reason - the build-up of CO2 will make the yeast go dormant or extremely sluggish depending on the strain.
Click to expand...

Ya jcaudill, that makes sense if your fermentation starts out sluggish, hit it with your filtered air. However, I can't comment on the effects of CO2 on the beer. From what I studied, there wasn't any mention of CO2 suffocating yeast. Especially since yeast don't breath. I'll have to look that up. But for now I'll stick with my initial training that CO2 doesn't suffocate yeast, especially since it blows off in the process. However, you got me thinking about it.
 
If it blows off I don't think there's any reason to think about it. It's the situation where the fermenter is capped and building CO2 that I was thinking about. But I'm not entirely clear if it's the CO2 that hurts the yeast or the pressure now. Or both!
 
dlester said:
O2 will oxygenate the beer, that will ruin it and make it taste like cardboard and make it dull. C02 will push the yeast back up the beer and wake it up.
Click to expand...

dlester said:
C02 is a by-product of alcohol production. It isn't going to suffocate the yeast, and it isn't going to restrict the yeast's job at converting sugars to alcohol either.
Click to expand...

But co2 is poisonous to yeast, that's why meadmakers degas during early fermentation- to stir out the co2 that stunts and slows the yeast. I think your last statement is not correct.
 
Yooper said:
But co2 is poisonous to yeast, that's why meadmakers degas during early fermentation- to stir out the co2 that stunts and slows the yeast. I think your last statement is not correct.
Click to expand...

I can assure you that I am not an expert on this matter and you certainly have a legitimate argument. So I contacted a person that specializes in yeast to see what they think on this matter. I'll report back when I hear back.
 
Yooper said:
But co2 is poisonous to yeast, that's why meadmakers degas during early fermentation- to stir out the co2 that stunts and slows the yeast. I think your last statement is not correct.
Click to expand...

I contacted a microbiologist that specializes in yeast to address your argument that CO2 is poisonous to yeast and slows fermentation, and the following is as follows:

He stated that CO2 can inhibit the speed of fermentation. However, he didn't believe rousing with CO2 would cause much of a problem because you are not dissolving lot of CO2 during this process and may cause more dissolved CO2 to be released from the beer. He determined that by releasing disolved CO2 within the beer solution, fermentation would increase.

It appears you are correct that CO2 can slow fermentation and venting off CO2 on your mead is beneficial. However, it also appears that when rousing the yeast with a blast of CO2, a certain amount of CO2 that was previously dissolved in the beer is vented off (I can attest that excess CO2 is blown off by watching CO2 given off over a certain period of time after the initial injection of CO2). Thereby increasing the speed of fermentation. How much? Who knows, and I'm not sure its worth the extra effort just to speed up fermentation. At least it appears that rousing yeast with a CO2 blast will not hinder the fermentation process overall and accomplishes my task at moving the yeast back up into the beer.

David
 
I'm here! Right - when I realized you weren't capped that is when I also realized what you're doing isn't a problem. For some reason I was thinking while capped (and if capped isn't a familiar term, I mean the fermenter is sealed - during a spunding or condition type phase).

Good to have an answer from the experts!
 
jcaudill said:
I'm here! Right - when I realized you weren't capped that is when I also realized what you're doing isn't a problem. For some reason I was thinking while capped (and if capped isn't a familiar term, I mean the fermenter is sealed - during a spunding or condition type phase).

Good to have an answer from the experts!
Click to expand...

Got ya, I understand your comment. My fermenter has a blow off at the top, but your comment brings up a good point. We all have bottled with sugar and capped it to carbonate our beer. That seems to work just fine.

Either way, it's good to have an expert help us out once in a while. And, thanks for your argument. it makes for a good conversation/thread.
 
dlester said:
Got ya, I understand your comment. My fermenter has a blow off at the top, but your comment brings up a good point. We all have bottled with sugar and capped it to carbonate our beer. That seems to work just fine.

Either way, it's good to have an expert help us out once in a while. And, thanks for your argument. it makes for a good conversation/thread.
Click to expand...

Ya what I'm referring to is pressurized fermentation though. Where you reabsorb the CO2 produced by the yeast into the beer to self-carbonate - aka spunding. This is the rheinheitsgebot mandate. And actually even rousing yeast with some CO2 while capped wouldn't be a huge deal because you're going to be killing them anyway.

Really my whole point was stupid but at least something good came out of it haha.
 

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