Yeast Quantities for in bottle Fermentation

[disgruntledgoat]

Hi guys, 1st post so unsure if it's int eh right place or not.

I currently have a strong, Trappist style, Belgian dark ale in prmary fermentation, it looks to be turning into a monster... I plan to secondary it for 2 or 3 weeks when the fermentation finishes and then, and heres the rub, referment it in the bottle, just like the pros.

Now, I'm confident I can follow the process, i've read Brew Like a Monk and a couple of great articles online, but nobody seems to be able to tell me how much yeast to use... BLAM said the Trappist breweries use about 1m cells per 500ml, so with my 23l batch this would give me a cool 56m cells. So how do I know how much that is? I used Wyeast 1762 in a smackpack at the outset and just mixed the lot into a 2l starter and pitched at 22c, however, I'm sure I don't want that much yeast again, so do I split one down, into what sort of quantity?

Secondly, can I use yeast I've harvested out of primary for the task? And if so, again, how much?

The beer had on OG of 1.080 and at last check, after 3 days of fermentation was down to about 1.018. It has been fermenting between 22c and 30c if that's any help!

Thanks in advance!

 

[phettebs]

I replied to your other thread but it was more about the temps. Are you wanting to re-yeast with a different yeast or use the same one with which you fermented? In the other thread, several others and I said you need to let this one age a while. If you are planning on bottling in 3 weeks and want to use the same yeast, there's still plenty left in suspension to carbonate your bottles. 1.080 is high but not exceedingly high to the point where the yeast is just tired.

I can't say that I have ever not re-yeasted a 1.080 or higher beer but it wasn't because of the gravity. I will let a beer that high age for a minimum of 2 months in secondary and probably more like 4 or 5 with some of it in a fridge.

For my first few, I dumped a whole packet of dried yeast into the bottling bucket and that was WAY too much. In later efforts, I tried a few teaspoons of rehydrated yeast and that ended up not being enough for the beer I was bottling and I ended up with a lot of flat bottles. I've been using just a half packet and that seems much better but I suspect it may still be too much. I'm guessing maybe 1/4 a pack might be better. Think I'll try that next time!

 

[evanvine]

I wonder if I may have some enlightenment here.
Won't a small amount of yeast multiply into a large amount and consume the sugar, and similarly, won't a large amount just consume the available sugar and then lie as a sediment? :wha:

 

[phettebs]

E,
That's kind of what I was getting at in a round about way. When I pitched a whole packet, I ended up with a LOT of sediment in my bottles. I've heard of some guys adding a single grain of dried yeast to a bottle before capping it. That seems painful to me because I'm lazy when it comes to bottling. I've never really been too bothered to experiment on the "right" amount!

I've had some really high gravity beers where I didn't add enough and after several months of conditioning, were still flat. Talk about a kick in the teeth! I should probably do some more quantitative testing but at the time I get to bottling, I just want to drink it!

Good luck dg and let us know how it goes!

 

[Aleman]

There is a good section on this in Chris Whites Book 'Yeast'. I forget teh details now, but Ideally you need 1 million cells per ml to carbonate beer . . . so for your average 500ml bottle, if you consider that dried yeast contains 20 billion cells per gram, you will need 500,000,000/20,000,000,000g of yeast (~0.025g) . . . It might perhaps be easier to batch prime, and add the yeast to the batch so for your 23L batch where the maths becomes 23,000,000,000/20,000,000,000 which is
23/20g or ~ 1.15g . . . not a lot at all.

Wet yeast and yeast slurry is a lot more complex, and I can't recall the figures of the top of my head as it involves a lot of assumptions.

Buy the book it's a damned good one, and I've not spotted any glaringly obvious mistakes yet . . . but I've only read it 4 times so far :ugeek: :ugeek:

 

[graysalchemy]

I bottled up some rather nice elderberry stout og 1080. It had lay around for 3 months so as I was bottling some bitter I added a few hundred mils into 9l of stout. My assumption was that this would just give the stout a little boost.

Was this terrible bad practice, Aleman?

Cheers

AG

 

[Good Ed]

For what it's worth, here's my pennysworth;

I made a gall of extract lager (Yobrew Pete's Lager) and had lagerered it in the fridge for 5 weeks; I bottled 9 x 500ml bottles, batch primed with 30g of glucose and made up a starter of the S-23 yeast I'd used to ferment it, and just added a couple of glugs of this (very precise), left in the warm for 24hrs then in the cellar at 15C, turned out very nice. What I noticed during the first week was that some sediment was clinging to the side of the bottles (clear bottles), so I gently shook the bottles until this settled, which it did and produced a nice clear beer with the sediment stuck nicely to the bottom. Needless to say 9 bottles didn't last long.

: