Reusing yeast cake
 

So let me get this straight, the yeast in the trub at the bottom of my fermentation buck can be racked upon for another go-round of fermentation with another 5 gallons of beer?

Is that a correct interpretation of you guys who've re-used yeast?

That is correct. If you do this however you may want to use a blow off because the initial fermentation is pretty violent.

You can do it, but you are massively over pitching. If you want to reuse it, I'd suggest you use the Mr Malty calculator to see how much slurry you SHOULD be using.

http://www.mrmalty.com/calc/calc.html

Select the "Repitching from Slurry" tab.

Hope this helps.

I think the consensus is that the yeast should be washed and then siphoned off and repitched. I am not sure about this though. Also I don't know how to siphon off the yeast since I would assume that requires a sterile siphon hose unless you don't have to worry about that since it's so much yeast.

The massive overpitching coming from the incredible multiplication during the first-use fermentation?

I believe because of the high amount of yeast cells that are present in the trub. For what it's worth, I'm doing the exact same thing today. It's a learning experience for me, too.

B

Well birvine, let me know how it turns out. It would be nice to save $6-8 bucks per batch as long as i have good yeasties still willing to work for me!

Are you just gonna rack right on top of some you had just siphoned off of?

In short yes. The yeast will also not reproduce for your new beer and you may be left with sub par ester flavors and mouthfeel.

There is a huge thread about this somewhere that I can't locate currently. I'm slammed at work or I'd try harder.

The consensus is that over pitching can lead to more problems that it is worth.
That being said, I do rack onto a cake for my big beers. My 1.139 RIS for example. :mug:

I've done this about a half dozen times in my 6 month brewing career ... and so far with great success ... once I even used the same cake 3 times ... I just always pitch a stronger, more hopped up, and darker beer than was on the cake previously ... I also scoop about half the cake out each time ... all advice I got on here, from folks who have been doing it for years ...

I'd just wash it, then you can save numerous jars of it for future use:
http://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/

I believe this is the thread tasq was referring to: http://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/