Yeast Cake lifespan and care

I have a batch in primary and am hoping to make another batch and just rack onto the yeast cake. Don't know that I'll be ready the same day to make another batch, is there a way to "save" the cake?

Brewstrong with Jamil and John P have at least one full podcast on how to do it. I did a simplified version of Jamil's system once where I sanitized some jelly jars and basically just poured some of the yeast from the bottom of the fermenter into them and then refridgerated. I did let out some gas after two days.

To check on repitching rates you can look to mrmalty.com

Leave some beer on top of it if you don't want to wash it. I've only done that for a couple of days though.

I harvest my yeast from the secondary after each brew. I simply leave a little beer in the carboy (as little as possible), swirl it around and pour it into a sanitized bomber bottle. I throw a bottle cap on it and stick it in the fridge. I've had great success with this technique and have left it in the fridge for as long as 3 months before starting a new batch.

After pitching my 3 month old 'yeast cake,' I had very active fermentation within 12 hours.

I did this yesterday.

I left a little beer on top of the cake and ended up using it about a week later (yesterday). Today, it seems to be happily chugging along.

There was a thread on here a while back about a guy who just left his out, without any beer on it. Said it got cracked and dry and whatever else, but I don't remember how long this was.

A couple of notes for anyone interested.

Pitching on a whole yeast cake minimizes the reproduction stage. This will reduce the contributrion of flavors in the beer from the yeast. Good for 'clean' ferments, but if you want fruity notes from English, or Belgian yeasts, they will be reduced. Recommend pitching 1/4 of the cake.

Continually harvesting yeast from the seconday will change the yeast characteristics. You are harvesting the yeast that didn't flocculate. The good ones are the ones that did all the work in the primary and flocculated out ... you left them in the primary.

As each generation reproduces, they will tend to reflect their parents, but there will be a variation. One generation from secondary will probably not change much, but a few generations will change the yeast. It's like tall people generally have tall kids, and small people have small kids; not always true, but is a general trend. Taking yeast from secondary you are selectively taking the yeast you don't want to have a clear beer.