Pitching on Yeast Cake

[Pinhead]

Yesterday I pitched a new batch of beer on top of a yeast cake of a beer that I had just moved to the secondary. Its bubbling along great and started with in an hour of pitching. This seems a lot easier then washing etc.

There must be some down side to this, What are the issues and how many times can you pitch on the same yeast cake?

 

[christpuncher123]

Depends how much Hops and trub are in your fermenter, and if the previous beer is higher in color and bitterness. I have had great success doing this with the same low gravity beers, but once I had to dump a batch because I forgot that I dry hopped in the previous one. I just started racking to secondary again after 7 years, what I have been doing is to rack the beer and some of the yeast off the bottom. A week later I pitch the new beer right onto that yeast, its a lot cleaner and seems to work great!

 

[Yooper]

Some reasons it may not be the best idea: https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/


I have done it in the past, but now I just use a portion of the slurry for repitching, according to the yeast slurry pitching calculator on mrmalty.com. Generally, it's about 150 ml of yeast for 5 gallons of a medium/high OG. A whole yeast cake is way too much.