pitching on top of a yeast cake

[bacchusmj]

a couple questions.

1) is it necessary to clean out the fermentor, or can you just pitch it into the dirty one (assuming there is no infection)?

2) if you have to clean out the fermentor, if I move the yeast to the second (clean) fermentor, is it cool to slosh the yeast into the new fermentor, or does it need to be pumped over?

3) any other suggestions? hints? tips?

Im being lazy and dont want to do a starter for a centennial IPA I plan to brew next week. I would rather just pitch onto an amber ale that is chugging away right now.

 

[sniperd]

I've repitched wort on top of a cake, no problem. I use glass fermenters, and the 2 times I've done this I just move my beer into a keg and leave maybe .5 inches of beer on the yeast.

Then the next day (brew day) I just put the wort into the fermenter. I don't clean the fermenter out (I spray a little star-san solution around the top) but it's still got that hard ring of yeast at the top.

Let me tell you, it works great. It's like making a massive starter. And the beer came out great.

I'm told you should only do this once or twice though on the same cake.

 

[Euphist]

I just recently did this. I transferred the first beer over to the keg while the second beer was chilling. Then the new batch got dumped on the cake. I figured that waiting to rack until the new one was ready would minimize infection risk.

 

[sniperd]

I just recently did this. I transferred the first beer over to the keg while the second beer was chilling. Then the new batch got dumped on the cake. I figured that waiting to rack until the new one was ready would minimize infection risk.

Good call on the minimizing exposure. I couldn't do it like that due to logistics so I left just a little fully fermented beer in there as that should protect the yeast cake. I also filled the top of the fermenter with c02.

 

[ShaineT]

Another option would be to do a quick yeast wash to move your yeast off all the break material and rack to another sanitized fermenter. Sounds like the IPA straight on top of the cake from your Amber would be fine though. Be prepared for a very fast start indeed.

 

[bacchusmj]

isnt the rule of thumb to work up in OG? my amber was 1.055 and the IPA will probably be around 1.066 (probably higher since my efficiency has been crazy lately)

 

[ShaineT]

isnt the rule of thumb to work up in OG? my amber was 1.055 and the IPA will probably be around 1.066 (probably higher since my efficiency has been crazy lately)

Probably would be best. Also working towards darker color with higher IBU than previous batch.

 

[BigFloyd]

For an ale of that gravity, scooping all but about 1/3 of the cake out of the fermenter will get you roughly the right number of cells (double the remaining amount for a lager of course). Leaving the whole thing would be an overpitch on anything other than a pretty big second beer (i.e., RIS, IIPA, Wee Heavy).

When pitching on an existing cake, a blow-off tube is strongly recommended.

 

[brokebucket]

I just did this for a RIS. My first time doing it, so I dont know what the "correct" way to do it, but here is what I did
-brewed my batch and put the wort in the fermenter to cool.
-bottled off old batch. Left 1/2" or so beer on top.
-Cleaned off the walls and lid of old bucket.
-when wort got to pitching temp, I dumped the wort violently on the cake.
-Transferred beer and cake back and forth several times.
-hooked up a blow off tube and waited. Yeast did not disappoint. Next day, it looked like an aquarium aerator.

 

[Yooper]

While I've done this in the past when making a "small beer" and then a "big beer", I've changed my ways and now pitch the proper amount of yeast as pitching onto the yeast cake is almost always overpitching.

Some food for thought: https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/

 

[philber]

...I've changed my ways and now pitch the proper amount of yeast as pitching onto the yeast cake is almost always overpitching.

+2 to that. I just did my 2nd reuse on the same S-05 with a high OG batch. In 6 hours it blew the top of my plastic bucket fermenter!

Typically I have done the 1st reuse with no issue. This is the first time I went to the 2nd reuse. I would highly recommend scaling back the cake a bit, but watch your sanitation.

 

[jtratcliff]

it's pretty easy to swirl up the trub/cake and pour some off before pitching. Leave about about a cup or two behind then pitch.

It's also very easy to wash the yeast you've just poured off.

 

[TKH]

While I've done this in the past when making a "small beer" and then a "big beer", I've changed my ways and now pitch the proper amount of yeast as pitching onto the yeast cake is almost always overpitching.

Some food for thought: https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/

That is an awesome, awesome thread! Thanks for sharing.