Using a 5 gallon yeast cake for a 20 gallon batch. Will this work?

[BarLee]

Hey brewers. As the title suggests. I have recently acquired all the equipment to do 15 to 20 gallon batches. 30 gallon kettle with a 5500w element and a brewing bag to do ebiab.
Still use my robobrew 35l for batches I enjoy and to try new recipes. My friends like my beer so I plan to brew larger batches to share. I have 1, 15 gallon batch that looks so far like a success. Can I use the cake off a five to feed the 15 or maybe even a 20? I make sure to use hop bags IF I dry hop. The whole purpose of course is to save a little on yeast. Hops and grain in bulk with a mill javereduced cost already. Made a dyi stir plate and am trying to figure that part out. Thanks all and Cheers to Beers
Oh and I make 5-6% brews for the most part.

 

[TennBrewer]

I think that would work ok provided you didn't underpitch the 5 gallon brew. I have used yeast from 5 gallon batches to repitch into 10 gallon batches and things go nuts, fermentation finishes in less than 2 days sometimes. I am sure that would be plenty for 15 or 20 gallon batches. Give it a shot and see what happens. Oh yeah, remember to keep everything extremely sanitized if not sterile, you don't want to spoil a big batch due to mishandling the yeast.

 

[day_trippr]

Assuming the respective OGs aren't stressing the yeast (more to the point, the 5 gallon batch) the full cake would likely be just about perfect for 20 gallons...

Cheers!

 

[Cptblamo]

If a pouch of white labs is (according to their website not the label) about 40-50ml for 100 billion cells, that's about half u would need for a strong pitch. 40-50ml is about a quarter cup of yeast. Therefore, you need about a half cup per 5 gallons. I would wash the yeast and see how much volume you have. If u have extra, good save some. If you dont have enough, make a starter.

 

[BarLee]

Thanks for all the replies! I am now going to give it a shot! Cheers and tha k you for sharing your knowledge.