Reusing yeast cake

So let me get this straight, the yeast in the trub at the bottom of my fermentation buck can be racked upon for another go-round of fermentation with another 5 gallons of beer?

Is that a correct interpretation of you guys who've re-used yeast?

That is correct. If you do this however you may want to use a blow off because the initial fermentation is pretty violent.

You can do it, but you are massively over pitching. If you want to reuse it, I'd suggest you use the Mr Malty calculator to see how much slurry you SHOULD be using.

http://www.mrmalty.com/calc/calc.html

Select the "Repitching from Slurry" tab.

Hope this helps.

I think the consensus is that the yeast should be washed and then siphoned off and repitched. I am not sure about this though. Also I don't know how to siphon off the yeast since I would assume that requires a sterile siphon hose unless you don't have to worry about that since it's so much yeast.

tasq said:

You can do it, but you are massively over pitching. If you want to reuse it, I'd suggest you use the Mr Malty calculator to see how much slurry you SHOULD be using.

http://www.mrmalty.com/calc/calc.html

Select the "Repitching from Slurry" tab.

Hope this helps.

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The massive overpitching coming from the incredible multiplication during the first-use fermentation?

I believe because of the high amount of yeast cells that are present in the trub. For what it's worth, I'm doing the exact same thing today. It's a learning experience for me, too.

B

Well birvine, let me know how it turns out. It would be nice to save $6-8 bucks per batch as long as i have good yeasties still willing to work for me!

Are you just gonna rack right on top of some you had just siphoned off of?

Zixxer10R said:

The massive overpitching coming from the incredible multiplication during the first-use fermentation?

Click to expand...

In short yes. The yeast will also not reproduce for your new beer and you may be left with sub par ester flavors and mouthfeel.

There is a huge thread about this somewhere that I can't locate currently. I'm slammed at work or I'd try harder.

The consensus is that over pitching can lead to more problems that it is worth.
That being said, I do rack onto a cake for my big beers. My 1.139 RIS for example.

I've done this about a half dozen times in my 6 month brewing career ... and so far with great success ... once I even used the same cake 3 times ... I just always pitch a stronger, more hopped up, and darker beer than was on the cake previously ... I also scoop about half the cake out each time ... all advice I got on here, from folks who have been doing it for years ...

I'd just wash it, then you can save numerous jars of it for future use:
https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/

I believe this is the thread tasq was referring to: https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/

Zaxxer - I was going to pitch directly onto the yeast cake then give it a very vigorous swirl to mix it in and oxygenate it. At some point I am going to wash yeast and save it in the fridge for future batches but that will come another day.

B

This past weekend, I racked a 1054 OG stout off a yeast cake of Wyeast 1056 and put the airlock back on the carboy, brewed an 1122 OG barleywine and pitched the chilled wort directly on the old yeast cake. I used Jamil's recipe, and note that Mr. Malty himself recommend this approach in his podcast regarding barleywines. I think most would agree that you would be overpitching if you aren't moving from a low-medium gravity beer to a high gravity beer as I did.

I'm not rich by any means, but I wouldn't risk $50 worth of ingredients to save $6 on a new smack pack if there were any risk to using this method. The only reason I did it is because I knew I needed a huge starter for this barleywine, and I'm not sure how to do that. I think I would have stepped up a 2L starter into a gallon jug, then stepped it up again into two separate gallon jugs. Then I would have to decant to get rid of all that wort, and then bring the yeast back up to pitching temp. That seems like a lot of work and introduces other types of risk into the process, and I still would not get the huge 5 gallon starter I ended up with. In my opinion, this is the perfect situation in which to pitch directly onto a yeast cake. In most any other situation, I would just buy a fresh smack pack and make a normal starter.

So say I am going to pitch from a glass primary. I would sanitize a funnel and my glass half gallon jug, pour in a gallon of cooled sterile water and once the beer is off the yeast cake, pour in the gallon and attempt to pour off the gallon of water into the half gallon container, avoiding trub, getting about a quart?

Thanks for the link btw, that is very helpful.

asterix404 said:

I would sanitize a funnel and my glass half gallon jug, pour in a gallon of cooled sterile water and once the beer is off the yeast cake, pour in the gallon and attempt to pour off the gallon of water into the half gallon container, avoiding trub, getting about a quart?

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It's a fine distinction, but the water doesn't have to be sterile. Sanitary, yes. And deoxygenated. Boiling takes care of both. Tap water, not distilled/RO.

I boil a growler submerged in a big pot.

Yea, with yeast in particular most literature says only used sterilized equipment but I have a feeling because it's going to be used within a few hours of getting captured it won't matter too much and won't lead to much contamination. I can't boil my growler as the glass will crack and the plastic funnel will melt and it would be much easier to use a siphon hose since it's hard to manage a glass carboy, but the syphon hose is plastic.

Cool, so basically... sanitize the growler, funnel and siphon hose. Boil about a gallon or 2 of water and let it cool. Get the beer out of the carboy. Pour in the sterile water, draw out the washed yeast with a siphon hose and into the growler. Wash out the glass primary, sanitize it, pour in the new wort and pitch with the contents of the growler.

Does this sound about right?