What to do with yeast at the bottom of my pressure keg??

[kenmc]

Hi,
well after posting my beginning questions about my first brew, I've drank a fair bit of it, primed and bottled another fair bit of it (drank one at the weekend - yummmmmmm!) and am coming close to the bottom of the keg. I presume there'll be a load of yeast down there.
I read somewhere that you can use that to start off the next batch - is that a good idea for a beginner? How soon would I have to use it? Does it have to be the same type of brew next time? Also this time I'm gonna beusing a 2 stage process as opposed to the "Mr Beer" all in one type thing I did before - would this be useful for that or not really? Am I best to just dump it for the moment?
Thanks
Ken

 

[D-brewmeister]

When people are discussing using yeast from fermentation to start a new batch, they are generally refering to using the yeast at the bottom of the primary fermenter in a two fermenter system. They use this yeast because it is the most active at that stage, having just converted most of the sugar in the batch. The problems with using yeast from secondary fermenters, or the sort of fermenter I think you are talking about is that the yeast will have started to go dormant, as the alcohol level and pressure stops them from actively fermenting. So in answer to your question, I would probably wait till you get your two stage system working before using the yeast slurry, and shoot for pitching the new batch on the old yeast (or bottling up the sludge for latter use) right at the point that the major fermentation activity has started to die down, usually about 5 days to a week into it. Don't wait till all the Krausen has setled down and the airlock has stopped clicking; at that point the yeast are already slowing down - try to get it when it is still clicking, just not a mile a minute like it is at the height of the ferment.

 

[kenmc]

cool thanks.
is there any particular way I should store it when I bottle it then? does it need to be kept warm/cool/bright/dark?
SO if I used the sludge then would i just dump that in instead of the yeast packet that comes with my kit? And how much of it should I use?
Sorry for all the questions - if there's somewhere you could point me with the answers please do - teach a man to fish and all that
Cheers
Ken

 

[homebrewer_99]

I generally bottle 2 bottles (22 oz) of yeast from every primary.

Be sure to keep a record of the labelling and keeping track of the oldest to newest yeast and style.

 

[D-brewmeister]

is there any particular way I should store it when I bottle it then? does it need to be kept warm/cool/bright/dark?
SO if I used the sludge then would i just dump that in instead of the yeast packet that comes with my kit? And how much of it should I use?

You definitely want to keep the yeast bottles cool and out of light. The cool temps insure that the yeast stay dormant, which is necessary if you don't want them to start trying to ferment, pressurizing the bottles too much and boom, bottle bombs. And generally you want to keep any beer stuff out of the light to avoid off flavors, though I imagine yeast is not as critical as brewed beer. Just use brown bottles and you'll be fine.

Now, as far as using the yeast, you want to take into consideration how long it has been stored, and how much yeast sludge vs. liquid you have in the bottles (the older the yeast, the more sludge you will want). As I said above, you keep the yeast cold to keep it dormant, which means you want to warm it up to wake it up. It is also strongly suggested to use a starter to insure the yeast are ready to go. Basicaly, you want to boil a mini-batch of wort, using malt extract or whatever (you can use sugar, but might get some cidery flavors from it), cool it to the same pitching temps you would use for a batch (70 deg. or so) and then add your yeast slurry to that. You will need some sort of smaller fermenter thing for this, be it a gallon jug that you can fit an airlock in or whatever, just make darn sure it is well sanitized, as with any batch. And when you open the bottles of yeast slurry, you will want to sanitize the lips somehow, either with a flame, or sanitizer or whatever. Cleanliness is very critical when dealing with yeast that have gone dormant, as the lag time between pitching yeast and active fermentation is the most vulnerable period in a beer's life (this applies to the main batch of beer as well). So when you see vigorous activity in your starter jar, brew your batch, cool it and pitch just like you would with liquid yeast. Hope this helps, and good luck!