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Re: wine yeast

Thanks to everyone who responded to my questions. Some follow-up questions:

Roger wrote:

>  Often when people report problems with maintaining activity in their yeast
>  batch the problem can be traced to a leak in their system.
Probably a good point, and relevant in my case. I have a hokey set-up, where 
I have two airlines, one coming out of the bottle, and one line running into 
the intake of the power filter. I have a cheapo valve connecting the 
two--mainly for the purpose of convenience. This way, the line does not have 
to be removed inside the tank, as it's a pain to get it positioned correctly. 
That connecting valve is a problem, but it's provided protection, for 
instance when my water hardness changed over the season and I had really 
potent batches, rather than pumping into the tank, it blew the valve, the 
lines flew apart, and the mess went on my walls rather than in the tank. 


Anyway, I've seen airline tubing sold specifically for co2 use. In the Pets 
Warehouse catalog, it says that typical airline tubing can lose a lot of co2, 
and they sell alternative tubing, which they claim doesn't. It is 
significantly more expensive than regular tubing, and it isn't silicone 
either. I don't know what it is, or whether it's worth it. Why does tubing 
lose co2, except at connecting points?

Robert wrote:

>   The stuff I have at home says it's "food grade urea" and something
>  else. Basically, yeast fertilizer. If you add enough yeast, then the
>  dead yeast will provide the nutrients.

This brings me back to a post I read several months ago. The author detailed 
out how yeast should be prepared to prevent bacterial contamination, etc., 
which will kill the bottle. I recall reading that if there was any collected 
stuff in the bottom, the bottle's a goner. I took this to mean that you don't 
want any dying yeast in there--once they die and you have contamination, 
forget it. 

>   I can believe it. I'm going through the same thing.

You have my sympathy.

Jamie wrote:

>  BTW, I wouldn't disturb the bottle once everything gets going. If you 
>  open the top and expose it to O2, it seems things go down hill fast. 
>  Keep everything sealed up until you're ready to change bottles. 
>  Keep the opened yeast packet in a ziplock bag in the frig. 
Bringing up that deposit on the bottom of the bottle again--the bottle needs 
to be shaken vigorously to get that stuff in the solution, whether it's 
settled yeast, or sugar, right? That really can't be done without removing 
the top with the airline attached, so I've in the past removed the top, put 
my palm on top firmly and shake till the bottom is clean. This couldn't be 
done with the top intact--mainly because the bottle has to be held 
upside-down or shaken sideways, because this settled stuff compacts. I have 
seen the mixture get really active and start frothing over the top if it's 
too active and the top is taken off. Is there another solution? I think that 
change in pressure? or meeting of O2 causes a subsequent drop in activity, 
once it gets recapped. Another problem for me.

Wayne wrote:

>  I would never start a new batch using yeast nutrient or energiser. If you 
>  this the production will be very high at first and then rapidly fall off.
>  This is not just useless but dangerous to your fish. I add baking soda 
>  helps to mitigate the initial CO2 production but also helps to prolong the
>  fermentation.

I find that addition of baking soda causes high yeast activity. I assumed it 
was helpful if water is soft, and had something to do with pH or kH increase. 
If added after a slow down, it also re-invigorates the bottle. I thought the 
*energizer* was something you'd use along the way as the mixture slows down. 
And the yeast nutrient was supposed to add longevity to the yeast, my 
thinking was that it should be added right away.
>  I always chart the CO2 production from my bottles and measure the drop in
>  S.G. from each batch. If you would like to see some of the results I can
>  Email them to you. It might give an idea of what to expect from a good
>  fermentation and/or when to add extra nutiton to the yeast.

I would like to see this. Previously, I assumed from other recipes, that once 
folks mixed up a batch, it was good to go for a month or two. Looks  like 
_some_ maintenance is normal and necessary.