Pitching On To Yeast Cake

[Snow]

Guys and gals,

I am planning to use the whitelabs London Ale yeast cake from the primary of an upcoming ESB to go straight into fermenting an Arrogant Bastard clone. What is the recommended process? Would it be ok for me to pitch straight onto the whole yeast cake, or should I just take a couple of cups of slurry and add that to the AB? I was kind of thinking that, as the AB will have such a high OG, that the whole yeast cake would be more beneficial to full fermentation, but I was worried about the impacts of hop flavours from the first brew affecting the second one.

What do you reckon?

Cheers - Snow.

 

[Murray]

Pitching onto the yeast cake will be fine, I've had no problems with carry over flavours. The general rule is to pitch increasingly darker and stronger beers, so you shouldn't have any trouble.

Having said that, a couple of cups well aerated should do just as well. You would have the advantage of being able to start a small amount of slurry early.

 

[Doc]

Snow,

What is the gravity of your first beer ?
If your second beer was a small/normal beer I'd be a little concerned, but you should be fine as the AB will be around the 1.075-1.080 mark. You might need a blow-off tube though.

Doc

 

[Kai]

Since you're doing a high OG beer, I wonder if there'd be any advantage to setting aside a cup or two of slurry and having a repitch later in the ferment?

 

[user 384]

I would be wary of pitching onto a whole yeast cake, remember you can overpitch as well as underpitch. From personal experince, I once (and it was just once) pitched onto a whole yeast cake and the fermentation was explosive. With such a large amount of bilogical activity it created a fair bit of heat and the brew ended up with some off-flavours.

Cheers
MAH

 

[Snow]

Good point, MAH. I never thought of the excess heat risk.

Doc, the ESB should be 1.045-7, so the AB will be way heavier at 1.075-7.

One option I was think of was taking 2 cups of slurry from the primary, then cleaning the fermenter out and pitching the 2 cups of yeast into the AB. Then if I have trouble getting the attenuation I need, I was going to have some whiskey or champagne yeast on hand to give it a boost. However, I wouldn't expect attenuation problems from the London Ale yeast if I aerate it all properly.

Cheers - Snow

 

[joecast]

One option I was think of was taking 2 cups of slurry from the primary, then cleaning the fermenter out and pitching the 2 cups of yeast

mind if i "borrow" that idea?
ive pitched on an entire yeast cake before and wasnt terribly happy with the results. im sure the fact it was a "small" beer had something to do with it, but an entire cake is A LOT of yeast.
what i am hoping to do is brew an ESB of around 1.045 OG and use the yeast from that to brew a ~1.080 OG double IPA. as well as not having to worry about over-pitching (which probably wont happen anyway), i can also use the yeast to make a starter and not have to brew the big beer the same day i rack the small one. just makes things less hectic.
joe

 

[mikem108]

That is the most appealing way for me as well, you end up with heaps of yeast anyway and the
fermentation goes off surprisingly fast. I've done up to 3 consective "repitchings" of yeast with no
ill effects.

 

[jayse]

I'll add my findings here snow.
I have done this many many times and it is generally the techniquie i ussually use.
For beers around 1.050 and under i just take 250mls of slurry and pitch into 3 litres of the wort i just made then after it starts showing signs of activity(which is not very long) i pitch it into the new batch or i just pitch it straight into the brew both way work just aswell. If the yeast has been under beer for 3 odd weeks i like to start it up with a few litres first though just for piece of mind.
I have also pitched many times with the whole yeast cake with no probs at all and thats what i did for the beer i called demon ale. You really don't need to worry about over pitching as most yeast cakes are not really any more than 500ml and i don't think that is over pitching for a big ale.
The problem of the heat may concern some so if you can control that by pitching at a lower temp and keeping it fairly cool your laughing.
Nothing in the hops that settle in the cake will affect the beer as all the stuff you don't won't from the hops settles in the hot break in the kettle if you don't transfer that to the fermenter than all should be fine.
Any hop matter that ends up in the fermentor after cooling the wort down etc i don't think can affect a big ale.

The tech heads will have some points about pitching lots at a low temp but on a small scale with 500ml pitched at 18c i have never had a problem.
I think you really have to over pitch by more than a whole yeast cake for those problems to come into play.


Cheers Jayse

 

[wedge]

If you had a few days....jar about 250ml of slurry with about the same of water. Shake sit, decant the water, refill, shake and decant. This should remove alot of the yuck stuff.

Though saying that i'm sure a big beer like the AB shiould be fine anyway.

 

[Hoops]

Wedge
I was thinking about your idea of adding a cup to cooled boiled water, I think that is a really good idea, that way you could get 2-3 lots of yeast if you wanted.
What i ended up doing Saturday though.....was pitching my brew onto the entire yeast cake of the previous brew.
This was with WLP001 Calafornia Ale and a Pale Ale with an OG of 1.062.
Within 12hrs it was fermenting at a great rate with a HUGE krausen. Next time though I would probably remove half the yeast cake. I don't think it's too much of a problem in Toowoomba at the moment with temps well below 10C but in summer without a fermenting fridge it would be a problem.
Adding the yeast cake to a double brew or splitting between 2 fermenters would be the way to go.

Hoops

 

[Snow]

Thanks Jayse, that's great advice. Bring on the AB!!

- Snow

 

[Darren]

If you had a few days....jar about 250ml of slurry with about the same of water. Shake sit, decant the water, refill, shake and decant. This should remove alot of the yuck stuff.

Though saying that i'm sure a big beer like the AB shiould be fine anyway.

Howdy wegde,
Just in case you didn't realise, it is the healthy yeast that stays in suspension and the dead cells and crud that falls to the botton first.
Darren

 

[DrewCarey82]

Guys when reusing the slush later.

I assume you just scoop some into a container, then what do you need to do and how long can you keep it for?

Heard and read a few different methods but none really have been explained to my understanding.

Cheers.

 

[DJR]

Guys when reusing the slush later.

I assume you just scoop some into a container, then what do you need to do and how long can you keep it for?

Heard and read a few different methods but none really have been explained to my understanding.

Cheers.

Hey, search on "yeast farming" there is a great post from Chiller if you're worried about storage. Quite involved but very good results.

You can just put wort on top of spent cake though, no problems.

 

[mje1980]

I do this a lot, and i just take about half of the slurry out, and it gets going within a few hours. No probs. I used a whole yeast cake once for a barley wine, and the beer went from 1090 to 1020 overnight, and eventually down to 1009, so, thats why i take half out.

 

[matti]

No problems here did this firsttime with me last aprtial with great results.

 

[Anachi]

I was talking to David Logsdon of Wyeast when he came down to melbourne. He was saying that overpitching is a large source of off flavors in beers as can not only lead to increased temprature but the rapid growth and fermentation (even if the temp is controled) will spit our a much larger amount of fusel alcohols and esters. Apparntly its better to slightly underpitch from the recomended amount for your gravity beer. (For a standard 23L batch with a grav of 1.040 you want about 200 Billion cells).

During fermentation the number of yeast cells should tripple or quadruple, so if you start with about 100 Billion cells (pitch the wyeast pack) then you will end up with around 300 - 400 cells, 20% will be dead by the end of fermentation so 240 to 320 billion live cells in your next batch. Which is not to much over suggested amounts for standard gravity beer, and about right for really high gravity beers (AB for example). If, however, you use a starter for your first beer your pitch rate will be much close to 200 billion, so you will be pitching b/w 480 and 640 billion cells, which is way too high and will probably do some damage to your subsquent beer unless its really big OG and then still I would be worried.

You also can only use your trub once, as if you repitched a third generation its going to be a bit mental. The other risk involved with reusing trub is the fact that yeast eat their dead counterparts for vital nutrients. In doing so they produce spoiling flavors. In high gravity beers you probably wouldn't see any negative effects from one repitch, but I would be worried about doing it in low gravity beers or for any more that two generations.

I am however not suggesting you waste your money on new yeasts for every beer, specially when wyeast recomend that most yeast strains should give you about 8 gen's before noticable mutation effects. As has been previously mentioned washing the yeast with cooled boiled water is very effective at remove the dead yeast cells and left over trub. A good guide to do this effectivly is on the wyeast website @ http://www.wyeastlab.com/hbrew/hbyewash.htm.

As for pitching amounts if you start of with a good started for your first gen, then you will have 480 - 640 good yeast cells in your repitch so about half your washed yeast is good for a higher grav beer, and less than half for a lower gravity beer. Dave suggests you err on the small side.

On a more personal note I have a few poor batches from pitching straight onto a yeast trub and don't see any good reason to do so when it is so easy to wash your yeast and obtain a good pitching size.

Hope this post is of help.

 

[Trough Lolly]

I was talking to David Logsdon of Wyeast when he came down to melbourne. He was saying that overpitching is a large source of off flavors in beers as can not only lead to increased temprature but the rapid growth and fermentation (even if the temp is controled) will spit our a much larger amount of fusel alcohols and esters. Apparntly its better to slightly underpitch from the recomended amount for your gravity beer. (For a standard 23L batch with a grav of 1.040 you want about 200 Billion cells).

Interesting...I don't count yeast cells, as some breweries do, but - with all due respect to Mr. Logsdon - I must confess that I find this whole argument of overpitching to be a bit of a furfy. *IF you have quoted him correctly*, he's blaming a large yeast cell count for fusels and esters in a temperature controlled ferment. Perhaps it's important for us to go back and have a think about what causes fusels and esters to be generated in the fermenting wort to begin with. I understand the theory espoused re overpitching, but to be perfectly honest, I would be more concerned about stressing an undersized yeast colony in wort than the potential for a large active yeast colony getting into the available sugars. The point here to consider is that the ability of each individual cell to attenuate the sugars won't necessarily change, it's just that there's a whole lot more cells doing the same thing...

During fermentation the number of yeast cells should tripple or quadruple, so if you start with about 100 Billion cells (pitch the wyeast pack) then you will end up with around 300 - 400 cells, 20% will be dead by the end of fermentation so 240 to 320 billion live cells in your next batch. Which is not to much over suggested amounts for standard gravity beer, and about right for really high gravity beers (AB for example). If, however, you use a starter for your first beer your pitch rate will be much close to 200 billion, so you will be pitching b/w 480 and 640 billion cells, which is way too high and will probably do some damage to your subsquent beer unless its really big OG and then still I would be worried.

I'm curious here, Anachi, as to where you sourced this info? And apart from the numbers quoted (which I'm not entirely comfortable with anyway) the important factor to consider is what's encouraging the yeast cell count to increase? A number of important things, such as the presence of Free Amino Nitrogen (FAN) which is an important source of Nitrogen for the synthesis of cell proteins. The research I have shows that cell growth peaks in the first 24 hours of primary fermentation and drops sharply thereafter, in almost direct correlation to the drop of FAN (and pH for that matter) as the wort ferments and becomes beer.

You also can only use your trub once, as if you repitched a third generation its going to be a bit mental. The other risk involved with reusing trub is the fact that yeast eat their dead counterparts for vital nutrients. In doing so they produce spoiling flavors. In high gravity beers you probably wouldn't see any negative effects from one repitch, but I would be worried about doing it in low gravity beers or for any more that two generations.

Ok, there's a fair bit wrong here - let me touch on them briefly...There are lots of brewers who have aseptic techniques, who have successfully used "trub" on more than one occasion. The subsequent generations to carry an increasing risk of genetic mutation, and there is always the chance that bacterial infection can occur, now matter how careful one is with their yeast slurry.
As for your description of yeast autolysis, allow me the luxury of quoting from an earlier post to save typing...

//engage beergeek mode//
Yeast require a number of nutrients for growth, including vitamins, minerals, carbs, nitrogen and trace elements (including copper and zinc). A good source of nitrogen comes from the amino acids found in the wort. Yeast cells use the nitrogen to develop cell proteins and other compounds. There are roughly 20 amino acids and they are commonly found in the malt extract / wort that we use in beer brewing. All of the wort amino acids and the small peptides are referred to as Free Amino Nitrogen or FAN. The FAN level in your wort is a good indicator of potential yeast growth and therefore fermentation performance. Cheap malt extracts are often low in FAN. A typical all malt freshly mashed wort has around 150 to 220 mg of FAN per litre. So any decent yeast nutrient should contain FAN...
Now, yeast has FAN levels of around 2% by weight, so, if you want to increase the FAN levels in your wort, you could toss in some yeast in the boil (I normally add it with about 10 mins to go). Ok so it doesn't add all that much FAN but it does also add some zinc to the brew - which is an important yeast growth contributor - and whilst it's not a lot, it's better than tossing the sachet into the bin...There are other contributors that the yeast cells surrender, such as Vitamin B, but I think you get the point without boring you with too much more detail!
The boil does kill the yeast and it violently erupts the cells - as opposed to the cell breakdown via autolysis - so the boil assists by releasing nutrients into the wort from within the cells and even the cell walls themselves, which will help the fermentation yeast that's eventually pitched after the wort is chilled. Some brewers add modest quantities of bakers yeast to their boil to provide a relatively cheaper nutrient to brewing yeast...
<snip>
Yeast autolysis (aka auto-self-lysis-splitting) , in very general terms, occurs when the existing yeast cells run out of sugars to consume in solution and the cells die through the action of their own enzymes which break down the cells structural molecules in order to find further nutrients - ie, it suicides out of starvation! It can occur if you left the yeast in the fermenter for an extended period of time, long after the fermentation had concluded. To avoid autolysis in the bottled product, it's wise to make the yeast cells dormant - by refrigeration, or, by pasteurising the beer and removing the yeast altogether from the brewed beer, or by racking the beer to reduce the cell count in suspension. Yeast autolysis does add significant levels of amino acids to the beer, as the walls rupture, but at this stage of the fermentation process, you wouldn't want to introduce amino acids (which tend to add to a fuller mouthfeel in the beer) via this process as the autolysing yeast adds substantial sulphur compounds to the beer and you'll get off flavours and a vegemite or meaty smell to the brew that may be impossible to remove.
...snip...

So, if you punish your yeast in a nutritionally poor environment, you encourage yeast autolysis - by feeding viable, non-mutant yeast cells with, say, fresh wort, you give the yeast a more attractive option than self destruction...

I am however not suggesting you waste your money on new yeasts for every beer, specially when wyeast recomend that most yeast strains should give you about 8 gen's before noticable mutation effects. As has been previously mentioned washing the yeast with cooled boiled water is very effective at remove the dead yeast cells and left over trub. A good guide to do this effectivly is on the wyeast website @ http://www.wyeastlab.com/hbrew/hbyewash.htm.

As for pitching amounts if you start of with a good started for your first gen, then you will have 480 - 640 good yeast cells in your repitch so about half your washed yeast is good for a higher grav beer, and less than half for a lower gravity beer. Dave suggests you err on the small side.

On a more personal note I have a few poor batches from pitching straight onto a yeast trub and don't see any good reason to do so when it is so easy to wash your yeast and obtain a good pitching size.

Hope this post is of help.

I'm sorry to see that you've had poor batches from pitching straight onto yeast trub - but I wouldn't simply put it down to excessive pitching sizes - there's a number of variables that may have contributed to the problem, such as wort and slurry composition, fermentation temps, yeast age and O2 levels during the adaptive phase etc let alone cell population size...

Cheers,
TL
((Apologies for the lengthy rant!)

 

[sah]

I've successfully pitched onto cakes with worts of higher or equal gravity as the first.

Sometimes I have had such a vigorous krausen in these cases though that it has escaped from the fermenter. I've had it completely discard the layered cling wrap cover and spew foam all throughout the fermentation fridge. So check on it every day.

Scott