Pitching on yeast cake -same beer ? And/or higher OG ?

I’ve searched and read several posts on pitching a new batch on top of a trub / slurry that was recently racked. Lots of people are saying to always go with a bigger and/or darker beer.

What happens however when you put the SAME beer on top of the slurry? i.e. make two batches of the same beer in a row and dumping the new one on the old slurry?

How much larger of a beer should you go with when pitching on a yeast cake?

I was thinking of making a 1040 Cream Ale, then dumping a 1047 Amber Ale on top and then perhaps another 1047 Amber Ale (or maybe bumping the OG up if needed).

I know some will say take some slurry out and clean fermentor out and use Mr Malty to figure out how much to repitch and while I’m considering this I’d like to get some opinions on doing what I was thinking above.

The usual side effect I see from pitching on a big cake are these:


Faster, more violent fermentation. This is a big deal, and its something you need to think about. More yeast means more heat, so if you don't have temp control, you're going to have issues.

"Cleaner" Beer. By cleaner, I mean less yeast derived flavor.



I pitch on cakes a lot. It works well.

Synovia said:

"Cleaner" Beer. By cleaner, I mean less yeast derived flavor.

Click to expand...

So it's not the best for beers that are dependent on yeast for the flavor like Belgians, hefeweizens, etc... But would be good for beers with "clean" yeast flavors like almost any American style.

The cake also takes up some space in the fermenter. So If your fermenter was kinda small to begin with you will probably loose some beer to blow off. I use the 6 gallon better bottles and some times I loose about a half gallon of beer during the ferment.