When I aerate in the carboy, I would assume the air in the carboy is filled with that which we take great care to stop from contaminating our wort. Is that true? Is this a concern?
Great!
Tilt the carboy 45 deg and shake/roll it back and forth.[/quote]
NO! Super dangerous. I know, you’ll say you’ve been doing it and it works fine. But you need to add “so far”.
[quote=“BrewBum”]I always listen to music when I brew, so I just rock the carboy for at least one whole song. Usually 3-5 minutes or so. Well actually, there are exceptions to that. Pink Floyd’s Shine On You Crazy Diamond Pt. 1 came on one time. I had to cut that one short because my arms were getting tired 
Next time you rock the carboy to music try Inagaddadavida by Iron Butterfly. I bet you will get one heck of a work out. That sucker is over 17 minutes long. But it has a fantastic drum solo! Now I am showing my age.
Air pump, inline hepa filter, and 2 micron ss stone. Its been working great for me even on brews up to 1.115, and best of all, it was cheap.
Pump, free
extra tubing, free
Hepa filter $5
SS Stone $5
[quote=“gregscsu”]Air pump, inline hepa filter, and 2 micron ss stone. Its been working great for me even on brews up to 1.115, and best of all, it was cheap.
Pump, free
extra tubing, free
Hepa filter $5
SS Stone $5[/quote]
where do you get stones for 5 bucks?
Good to know. I was doing the same as you Ken.
Thanks.[/quote]
You are very welcome.
What I also mentioned over in the other conversation was that I was noticing that the starters I made with pure O2 seemed to get off to a nice start and get active quite quickly. I was thinking that yeast that is going into a starter is looking for oxygen RIGHT NOW so the O2 in the starter wort was beneficial. I’m in deep water because I don’t really know the science behind this but I know the way my starters have been behaving lately with the O2. If I make another starter soon (without O2) and see that it’s off to a sluggish start, I might raise an eyebrow.[/quote]
I can’t say I know the science either, but I had thought the advantage of a stir plate was to make sure that the yeast cells don’t deplete the nutrients in their local environment and have to wait for diffusion to bring new nutrients to them. By keeping everything mixing constantly, the yeast always have the best possible access to what nutrients there are, and thus will replicate faster. Of course, mixing will also keep the dissolved CO2 low and O2 as high as the atmosphere in the flask will allow, and there is no doubt that is also contributing. Perhaps more than the mixing. Like I said, I don’t claim to know the science.
[quote=“grainbelt”][quote=“gregscsu”]Air pump, inline hepa filter, and 2 micron ss stone. Its been working great for me even on brews up to 1.115, and best of all, it was cheap.
Pump, free
extra tubing, free
Hepa filter $5
SS Stone $5[/quote]
where do you get stones for 5 bucks?[/quote]
Buy, Borrow, or Build a time machine and head back the NB retail store in 2009.
[quote=“gregscsu”][quote=“grainbelt”][quote=“gregscsu”]Air pump, inline hepa filter, and 2 micron ss stone. Its been working great for me even on brews up to 1.115, and best of all, it was cheap.
Pump, free
extra tubing, free
Hepa filter $5
SS Stone $5[/quote]
where do you get stones for 5 bucks?[/quote]
Buy, Borrow, or Build a time machine and head back the NB retail store in 2009.[/quote]
I have had my stone longer than that and it was not 5 bucks
They may have given me a deal, I spent a LOT of time there when I started brewing. It was not uncommon to stop there 2-3 times a week back then, especially since it was on my way to and from work.
who hasnt
[quote=“rebuiltcellars”]
I can’t say I know the science either, but I had thought the advantage of a stir plate was to make sure that the yeast cells don’t deplete the nutrients in their local environment and have to wait for diffusion to bring new nutrients to them. By keeping everything mixing constantly, the yeast always have the best possible access to what nutrients there are, and thus will replicate faster. Of course, mixing will also keep the dissolved CO2 low and O2 as high as the atmosphere in the flask will allow, and there is no doubt that is also contributing. Perhaps more than the mixing. Like I said, I don’t claim to know the science.[/quote]
As mentioned in this article
http://braukaiser.com/blog/blog/2012/11/03/estimating-yeast-growth/
by Kai, that appears to be correct
So in other words, the observed decline in yeast growth for increased amounts of yeast as found in CW and JZ’s yeast book, may be due to more and more cells not having access to the nutrients required for cell growth because they’re stuck under more and more yeast sediment? Does that sound right?
If that’s true, then it appears the main benefit of a stir plate is NOT oxygenation but to stir all the cells around so they have equal access to nutrients. I have to assume there is “some” oxygenation during the process but it makes me wonder if there is some benefit to adding additional oxygen.
[quote=“mattnaik”][quote=“rebuiltcellars”]
I can’t say I know the science either, but I had thought the advantage of a stir plate was to make sure that the yeast cells don’t deplete the nutrients in their local environment and have to wait for diffusion to bring new nutrients to them. By keeping everything mixing constantly, the yeast always have the best possible access to what nutrients there are, and thus will replicate faster. Of course, mixing will also keep the dissolved CO2 low and O2 as high as the atmosphere in the flask will allow, and there is no doubt that is also contributing. Perhaps more than the mixing. Like I said, I don’t claim to know the science.[/quote]
As mentioned in this article
http://braukaiser.com/blog/blog/2012/11/03/estimating-yeast-growth/
by Kai, that appears to be correct
So in other words, the observed decline in yeast growth for increased amounts of yeast as found in CW and JZ’s yeast book, may be due to more and more cells not having access to the nutrients required for cell growth because they’re stuck under more and more yeast sediment? Does that sound right?
If that’s true, then it appears the main benefit of a stir plate is NOT oxygenation but to stir all the cells around so they have equal access to nutrients. I have to assume there is “some” oxygenation during the process but it makes me wonder if there is some benefit to adding additional oxygen.[/quote]
I was never under the impression that a stirplate was for oxygen intake. I assumed it was for having everything in the flask mixing at all times so that the yeast was in contact with the nutrients constantly. So I was surprised when the notion came up that hitting a starter with O2 was not necessary. I know many, many brewers who do this.
[quote=“mattnaik”][quote=“rebuiltcellars”]
If that’s true, then it appears the main benefit of a stir plate is NOT oxygenation but to stir all the cells around so they have equal access to nutrients. I have to assume there is “some” oxygenation during the process but it makes me wonder if there is some benefit to adding additional oxygen.[/quote][/quote]
That’s the way I’ve always looked at it. The oxygenation is a secondary benefit.
[quote=“Ken Lenard”][quote=“mattnaik”][quote=“rebuiltcellars”]
I can’t say I know the science either, but I had thought the advantage of a stir plate was to make sure that the yeast cells don’t deplete the nutrients in their local environment and have to wait for diffusion to bring new nutrients to them. By keeping everything mixing constantly, the yeast always have the best possible access to what nutrients there are, and thus will replicate faster. Of course, mixing will also keep the dissolved CO2 low and O2 as high as the atmosphere in the flask will allow, and there is no doubt that is also contributing. Perhaps more than the mixing. Like I said, I don’t claim to know the science.[/quote]
As mentioned in this article
http://braukaiser.com/blog/blog/2012/11/03/estimating-yeast-growth/
by Kai, that appears to be correct
So in other words, the observed decline in yeast growth for increased amounts of yeast as found in CW and JZ’s yeast book, may be due to more and more cells not having access to the nutrients required for cell growth because they’re stuck under more and more yeast sediment? Does that sound right?
If that’s true, then it appears the main benefit of a stir plate is NOT oxygenation but to stir all the cells around so they have equal access to nutrients. I have to assume there is “some” oxygenation during the process but it makes me wonder if there is some benefit to adding additional oxygen.[/quote]
I was never under the impression that a stirplate was for oxygen intake. I assumed it was for having everything in the flask mixing at all times so that the yeast was in contact with the nutrients constantly. So I was surprised when the notion came up that hitting a starter with O2 was not necessary. I know many, many brewers who do this.[/quote]
its always been both…to oxygenate and to keep yeast in suspension and not drop out
Thanks to all for sharing their preferences- I learned a few things as well.
:cheers:
