Dumping wort onto Yeast Cake

I'm making a Porter and I want to try dumping it on my 1728 Yeast cake right after I rack my Scottish 80/- to secondary. How do others do this? Just let 'er rip from the brew kettle and aerate/rouse after the transfer? Otherwise, I can just rack the Scotch Ale and then pull some of the cake to make a starter for the Porter. The Scotch Ale has been in primary for two weeks, so is this yeast going to be okay without making a starter?

Thoughts?

I just dump it and stir. I've dumped on cakes after letting the first beer sit for a month without any problems. I've found it is a good idea to cool the fresh wort to the low end of the yeast's temperature range, that prevents an explosive fermentation.

Dittos. I just put a barleywine onto the yeast from a brown ale and fermentation got very critical very fast. I had a blowoff tube on and it still knocked the lid on my fermenter loose. I had kreusen coming out of the blowoff tube within about 2 hours. It fermented the barleywine from 1.090 to 1.013 within 3 days.

Individual results may vary. Consult your physician if you experience dizziness, constipation, warts or your fermenter lid impacts the ceiling.

I just grab some of the cake. A cup or two. Put it a sanitized container. Clean the fermenter, and then add the saved. yeast.

Works for me.

Thanks! Given the small amount of headspace in my primary vessel, I think I'll make sure it's in the high 50's for temperature before pouring. That shouldn't be a problem, as we are on well water and it is a pretty constant 54*F all year round.

This is probably unnecessary advice but don't use an airlock until it calms down. Start out with a blowoff tube.

I've heard or read somewhere on here that a beer made with a yeast starter and the proper amount of yeast will always be better tasting than when over pitching like we would be doing in this example. With that being said I have used this method of fermentation and it works. I just put the tube from my counterflow chiller in the top of the fermenter and just let it hit the cake on it's way in.

racin_ny said:

I've heard or read somewhere on here that a beer made with a yeast starter and the proper amount of yeast will always be better tasting than when over pitching like we would be doing in this example. With that being said I have used this method of fermentation and it works. I just put the tube from my counterflow chiller in the top of the fermenter and just let it hit the cake on it's way in.

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I think it would be a stretch to say always, but probably safe to say there will be a different taste between repitching on a yeast cake and a normal pitch. Whether the difference is noticeable to most people would be another question entirely.

The two main differences I'm aware of are:
1) you won't get as many esters and flavor compounds from the yeast that are produced during the growth phase, because they don't need to go through the growth phase on the second ferment, or at least not as much of one.
2) its easier to get elevated temps with a massive pitch because your temps is going to rise faster when fermentation starts, but if you have good temperature control you should be able to manage that.

anyways, i've never pitched on a yeast cake, so you can take everything with a grain of salt, but those are a couple of the potential concerns with pitching onto a full yeast cake vs. recovering it and pitching a "correct" amount of yeast.

My method is to grab about 250ml to 1L of slurry from the bottom of the fermenter after bottling/kegging and pitch into the new beer. I don't like the idea of all of the trub and dead yeast (Sometimes almost 1Gal) getting into my new beer.

Just in case, I grabbed a sample from the bottom valve and pitched a starter today so if I change my mind I've still got some yeast RTG. Thanks again for the help!

Explosive fermentation? Blowoff tube? I pitched onto a whole yeast cake and the fermentation was about as slow as normal with a single packet of dry yeast. Of course I had cooled the wort to about 60 F. and put it into a room where it maintained 62 degrees ambient.

RM-MN said:

Explosive fermentation? Blowoff tube? I pitched onto a whole yeast cake and the fermentation was about as slow as normal with a single packet of dry yeast. Of course I had cooled the wort to about 60 F. and put it into a room where it maintained 62 degrees ambient.

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Really depends on the yeast. Hefeweizen yeast (WLP300/Wyeast 3068) is fun to watch.

RM-MN said:

Explosive fermentation? Blowoff tube?

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Yes and yes. I had a bucket lid fly off after pitching a Tripel onto 1/3 of the cake from a Patersbier. And I had added Fermcap S to reduce the krausen. Lag time was under two hours and she had blown about 9 hours into the fermentation.

I've done it both ways with a yeast cake. Removed about 2/3 with a sanitized cup, then pitched right on top. And I've done it where I save 1/3-1/2 of the cake, wash it, and pitch it into fresh wort and a cleaned/sanitized bucket.

The first method was easier and I had good results. The second method would be safer and more appropriate if you didn't want the flavor from the first batch to be imparted into the second (that one is in primary right now, but I'm assuming also good results).

You'll get a great fermentation by pitching on a full yeast cake, no doubt...but the best beer, well thats an item of debate. Ok actually its not an item of debate. Jamil and Co., as well as most all brewing scientists agree that overpitching (which will always happen when fermenting 5 gallons of beer on a full yeast cake) is detrimental is producing great tasting beer. If you dig around alittle, you get more details on that. Generally I try to use Mr. Malty when determining how much yeast to use. Admittedly, its an inexact method without a starter when you don't know the yeast viability. The last beer I brewed was a 10% abv RIS, and so for that one I used slightly less than half of a yeast cake from a low abv cream ale.

Thank you Newton.

Newton said:

Jamil and Co., as well as most all brewing scientists agree that overpitching (which will always happen when fermenting 5 gallons of beer on a full yeast cake) is detrimental is producing great tasting beer.

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Whom has also said underpitching is far worse than overpitching.

Underpitching/overpitching...they can both be bad for optimal tasting beer. But then again, this is homebrewing and for each his own. After about 3 years of it, I'm of the school of thought that I want to optimize my batches the best I can. One thing I've learned beyond a shadow of a doubt is that the correct amount of healthy yeast can be the deciding factor between a decent batch and an outstanding beer.

Absolutely. I think pitching rate is the least important when you're trying to fine tune fermentation. Pitch one vial per 5 gallons as a baseline then worry about fermentation control, oxidation, etc before you go counting cells and pitching based on gravity.

Weizenwerks said:

Absolutely. I think pitching rate is the least important when you're trying to fine tune fermentation. Pitch one vial per 5 gallons as a baseline then worry about fermentation control, oxidation, etc before you go counting cells and pitching based on gravity.

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I disagree. Pitching rate is as important as temperature control. But overpitching is less of an issue than underpitching. Pitching a single smackpack into a 5 gallons of 1.080 wort will cause more problems than dumping it on a yeast cake. Saying to ignore pitch rate and focus on oxidation problems is bad advice imo.

seabass07 said:

I disagree. Pitching rate is as important as temperature control. But overpitching is less of an issue than underpitching. Pitching a single smackpack into a 5 gallons of 1.080 wort will cause more problems than dumping it on a yeast cake. Saying to ignore pitch rate and focus on oxidation problems is bad advice imo.

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Oxidation will kill your beer faster than pitching the wrong amount of yeast.

Im not saying to ignore oxidation. Just that underpitching will give some weird off flavors. Its easy enough to make a starter.

Here's a quick AAR:

First of all, I just scooped out some of the cake and threw it in a jar for storage/washing later on, and dumped my wort onto the rest of the cake/trub. I'm really liking the 1728, so I think I'll make a Scottish IPA or something with it next.

Fermentation started within about 30 minutes, and was VIOLENT. The vent line plugged twice and almost blew the top off the bucket. When I came home from work the second day, the lid was whistling from the pressure escaping! Lesson; buy a freakin' 6.5gal. bucket or carboy for primary. Temperature went from 58*F at pitching to 66*F and stayed there for about 36 hours, then dropped to about 58-60*F since then.

OG was 1.060 (this is the NB St. Paul Porter kit, but I threw in a bit more DME for some more ABV) and after three days it was at 1.020, and hasn't moved since. I'll keep it in primary for at least another 1-2 weeks, and then move it to secondary for a few weeks before bottling. It's got an incredibly malty coffee smell to it, and a nice light color and mouthfeel, but holy living s**t is it hoppy and bitter. I'm really hoping that settles down after aging, as I really don't like a ton of IBUs in a porter.

Thanks for the help, gentlemen!