Reusing yeast cake for a lower gravity beer?

[luckybeagle]

Hi all,

I brewed a Belgian Tripel (OG: 1.081, FG: 1.011, ABV: 9.2% approx) and plan to bottle it within the next few days. I used the Belgian Ardennes Yeast (WY3522) and want to reuse the yeast cake for a Belgian Dubbel. I love this yeast!

The Dubbel's OG should be around 1.070. The Ardennes yeast attenuates 74% on average according to Wyeast, but I somehow achieved 86% with the large starter I pitched. My questions are:

1. Since the OG is 11 points lower on the Dubbel than the Tripel, would it be a harmful overpitch to simply rack the new beer directly on top of the yeast cake (immediately after racking the tripel into my bottling bucket?)
2. Is it reasonable to expect a similar attenuation percentage in this new batch?
3. Is there a way to calculate how much of the yeast cake I should use if I can't simply rack on top?
4. Lastly, since I'm going from a light beer to a higher SRM beer, is there any need to clean the carboy and remove, build a new starter, crash, decant, etc, some of the yeast cake if I can't use it all in the next batch?

 

[chewyheel]

I think reusing the entire yeast cake might be a little much. IMO you'd be better off saving the yeast cake and repitching it for more beers later. I like to used sanitized mason jars for yeast storage, I usually get four 16 oz jars from one yeast cake, (trub and all, no need for washing IMO). Date them and put them in the fridge. You should achieve a similar attenuation, because that yeast cake is going to have a TON of yeast in it, much more than you'd get from a liquid pack. In my experience one 16oz jar is good to use as a repitch. I just take it out of the fridge, let it warm up a bit, give it a good swirl and dump in in the new wort.

When I first started reusing yeast, I pitched a 32oz of a 34/70 yeast cake in a 1.060 wort and it absolutely ripped through fermentation, I got to FG in 3 days. I was able to keep the temp in check but the aroma was definitely a little off, which I think came from the extreme amount of yeast I used.

 

[luckybeagle]

Thanks for the great response! Rather than putting the entire yeast cake in the refrigerator, though, what do you think about putting half of the cake in a sanitized Mason jar, and the other half in the new car boy? Is there any need for it to sit in the refrigerator, since I will not be washing it at all anyways?

 

[chewyheel]

No need to refrigerate the stuff still in the carboy if you’re going to be racking wort onto it immediately. The other half in the mason jar should be kept in the fridge for future use

 

[brownni5]

Hi all,

I brewed a Belgian Tripel (OG: 1.081, FG: 1.011, ABV: 9.2% approx) and plan to bottle it within the next few days. I used the Belgian Ardennes Yeast (WY3522) and want to reuse the yeast cake for a Belgian Dubbel. I love this yeast!

What? You're going Belgian after a Belgian without 7 NEIPAs in between? You and I could be drinking buddies!

Good luck with the yeast cake - nice to find a strain you like.

Report back with your take on yeast performance. Some would say don't reuse yeast after a high OG beer. I say find out for yourself - Brulosopohy "disproves" lots of home brewing schools of thought.

 

[filthyastronaut]

Whole yeast cake is definitely too much, I go with 1 billon cells per ml, so if I want 200 billion cells, that'd be 200 ml. Of course that's a rough number, but it works for me. I found when I used to use a pint of yeast per batch, after reusing the yeast for a few generations, I would often get acetaldehyde specifically, likely because the yeast barely goes through a growth phase between pitches and it's eventually quite taxing for yeast health.

 

[luckybeagle]

What? You're going Belgian after a Belgian without 7 NEIPAs in between? You and I could be drinking buddies!

Haha, yesss!

My wife keeps telling me "brew what you like to drink--brew for yourself." I guess that's good advice! It's tempting to slip something in that I'm not crazy about just to give it a go (like a pale or an IPA) but... why?

I'm tempted to try a Quad rather than a Dubbel for my next. My local example that I loved before it was discontinued was produced by Claim 52, called the Olivia 9--a Belgian style Quad. I've also had one Westy XII (photo below) when I lived overseas and was smitten. Might as well try to get somewhat close to my all time favs.

I won't be able to reuse the Ardennes yeast cake for that one (recipe calls for WY1214 - Belgian Abbey), but I can split it/save it and do a La Chouffe Blonde with one and a Westmalle Dubbel with the other. We'll see how it goes! I'll be sure to report back on how reusing a yeast on another higher gravity ale turns out.

 

[Dgallo]

Depends on how soon you’re going to brew. If it’s going to be within a few days you can rack right on top of it as long as you keep it clean and cool. If it’s going to be a little while, properly sterilize utensils and a mason jar and save about half that volume and refrigerate. Then do a starter before you pitch to insure healthy active fermentation

 

[chewyheel]

Whole yeast cake is definitely too much, I go with 1 billon cells per ml, so if I want 200 billion cells, that'd be 200 ml. Of course that's a rough number, but it works for me. I found when I used to use a pint of yeast per batch, after reusing the yeast for a few generations, I would often get acetaldehyde specifically, likely because the yeast barely goes through a growth phase between pitches and it's eventually quite taxing for yeast health.

So you usually pitch 200 ml of a yeast cake for an ensuing 5 gallon batch of regular strength wort?
I’m still pretty new to reusing yeast and am trying to figure out the best method.

 

[Dgallo]

So you usually pitch 200 ml of a yeast cake for an ensuing 5 gallon batch of regular strength wort?
I’m still pretty new to reusing yeast and am trying to figure out the best method.

I don’t want to answer for him but for a beer with gravity 1.050 and lower you 100-150 Billion cells is adequate for a proper pitch and clean fermentation. 1.050-1.075 you should have 200-400 Billion. Brewers friend has an accurate calculator https://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/
If you go by @filthyastronaut estimation of how much volume of the cake you need that should work. I would guess that since it was the cake from a big beer, some of the viability of the yeast has been lost due to the ABV, that you’ll still want to do a starter with the yeast you save.