What is yeast cake??

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Yes - make your next batch and pour the wort directly on top of the yeast from the last batch - watch it take off in 2 hours....
 
Is it supposed to be hard. If not how do you get all former batch out? Can it only be used for the same type of beer again? I just kegged the first batch I ever made. There was a layer of white goo at the bottom. Did I do something wrong?
 
it depends on the type of yeast. some will pack in tighter than others. check the flocculation rating on your yeast. higher flocculating yeast will pack in tight low flocculating yeast will stir up if you sneeze to hard near them.

you siphon any batch of beer off the yeast cake, don't pour. your racking cane, hopefully an auto-siphon, will have a little cup on the end to keep it off the yeast.

the yeast at the bottom can be used again for any recipe that uses the same yeast. typically you don't want to use a yeast cake from a dark beer on a light beer because there may be some color and taste bleed over.

that white goo was yeast. if its in the keg then you either racked to soon or you poured your beer and disturbed the yeast.
 
Is it supposed to be hard. If not how do you get all former batch out? Can it only be used for the same type of beer again? I just kegged the first batch I ever made. There was a layer of white goo at the bottom. Did I do something wrong?

That layer of white goo is "trub". It's spent yeast, coagulated proteins, hops debris, etc. Sometimes it's fairly compactly packed, sometimes not. Some yeast strains will form a very tight yeast cake, some will not. Generally, the longer it sits, the more firm the yeast cake will be. I like to move the fermenter to where I'm racking the night before, if possible. That way the trub can resettle to the bottom overnight.

When I rack, I just siphon from above that yeast cake. Sucking up a little of the yeast won't harm a thing, as it'll just settle to the bottom again in the bottle or keg.

If you're reusing the yeast cake, the general instruction is to go from a lower gravity beer to a higher gravity beer, and lighter color/flavor to darker. You could easily put a big stout with an OG of 1.080 on a 1.040 cream ale yeast cake, for example. But I wouldn't do the reverse- you'd have darker color and flavors, as well as some stressed yeast.

I like to wash my yeast and save it for reusing. I have many jars of yeast in my fridge, saved from prior yeast cakes. We have a thread on "yeast washing" that can really help if you'd like to try that.
 
I've got some questions about the yeast cake:

1. Is it possible to remove the layer of trub from a fermenter with out disturbing the yeast layer? Does this depend on the flocculation of the yeast? How important is it to re-sanitize around the yeast cake before you drop the new wort on it?

2. I want to do this! I've ordered the making of an American Amber using Wyeast American Ale II yeast. After I brew that and let is sit in primary for three- four weeks, I was thinking of brewing a Stone Ruination Clone. The Ruination clone recipe calls for Wyeast London ESB strain, not American Ale II, although those strains are very similar in attenuation, flocculation, temp, etc. Would it be ok to throw the Ruination onto the pre-used yeast cake?
 
If you're reusing the yeast cake, the general instruction is to go from a lower gravity beer to a higher gravity beer, and lighter color/flavor to darker. You could easily put a big stout with an OG of 1.080 on a 1.040 cream ale yeast cake, for example. But I wouldn't do the reverse- you'd have darker color and flavors, as well as some stressed yeast.

Is this just true if you're aiming for a lighter beer? I was thinking of putting a Belgian Blonde type recipe on top of a yeast cake from a Triple that I'm about to bottle next week. I was hoping this would make the Blonde "bigger" than normal. Or will it totally ruin it?

From what I've heard it's much harder to ruin a beer as opposed to just not get out what you intended to put in. I just want to make sure what I'm about to do doesn't make for something that's undrinkable. A surprise wouldn't be something I am opposed to however.
 
I've got some questions about the yeast cake:

1. Is it possible to remove the layer of trub from a fermenter with out disturbing the yeast layer? Does this depend on the flocculation of the yeast? How important is it to re-sanitize around the yeast cake before you drop the new wort on it?

nope - they're mixed together pretty good - Yeast Washing if you want to separate. No need to sanitize - it had wort on it, you're putting wort on it. Just make sure your transfer devices are clean and sanitized. A fresh wipe around the neck (if carboy) and you're good to go.

2. I want to do this! I've ordered the making of an American Amber using Wyeast American Ale II yeast. After I brew that and let is sit in primary for three- four weeks, I was thinking of brewing a Stone Ruination Clone. The Ruination clone recipe calls for Wyeast London ESB strain, not American Ale II, although those strains are very similar in attenuation, flocculation, temp, etc. Would it be ok to throw the Ruination onto the pre-used yeast cake?

Yes, I'd throw the clone on top - just keep notes, so you know how to repeat it if/when it turns out awesome.
 
Thanks for the tips on what beer types you can move washed yeast to. Yeast washing is what promted the original question.
 
Is this just true if you're aiming for a lighter beer? I was thinking of putting a Belgian Blonde type recipe on top of a yeast cake from a Triple that I'm about to bottle next week. I was hoping this would make the Blonde "bigger" than normal. Or will it totally ruin it?

From what I've heard it's much harder to ruin a beer as opposed to just not get out what you intended to put in. I just want to make sure what I'm about to do doesn't make for something that's undrinkable. A surprise wouldn't be something I am opposed to however.

You don't want to put a blonde on a cake from a triple. A triple is a very high OG beer, and the yeast will be stressed. Also, you'd be overpitching by quite a bit. You could go the other way- from a blonde to a triple, since you need more yeast for a triple, but you don't want to put a low gravity blonde onto the triple cake.

You could use a portion of the yeast cake if you really want to. I wouldn't, because the yeast is pretty stressed from the high gravity fermentation, but you could consult mrmalty.com's yeast pitching calculator to determine the correct amount of yeast to use out of the remaining slurry.
 
What is the issue with over pitching yeast? I mean what does it do to the beer?

I was curious about this as well. I've never done a batch with the yeast cake from a prior batch. Overpitching could be an issue then, correct?
 
I was curious about this as well. I've never done a batch with the yeast cake from a prior batch. Overpitching could be an issue then, correct?

no idea.. I have a centenniel blond in the fermentor right now...planning on going to secondary next week . I wanted to brew another centenniel blond ( friends all love it) the same day I transfer and just pour it right on the yeast cake. some say no problem.... others say wash the yeast....I am confused
 
I was curious about this as well. I've never done a batch with the yeast cake from a prior batch. Overpitching could be an issue then, correct?

Yes. From White Lab's website:

If the beer is overpitched, yeast do not grow though a complete growth cycle. This results in few new yeast cells, which makes for unhealthy yeast and low viability by the end of fermentation.

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To me, the issue would be more off-flavors from the stressed yeast. You'd be using yeast from a high alcohol environment, from a high gravity fermentation, to ferment a lower OG beer.

In order to have the best results in brewing, ideally you'd use the healthiest yeast you could. Using unhealthy yeast, and overpitching besides, may be just as bad as severely underpitching the yeast.

I wouldn't do it. If I wanted to use that yeast again, I'd at least do a basic yeast washing procedure.
 
ok another question....if the yeast are viable, why do they not ferment the beer out dry? w
Why do they quit before 1.000???
 
ok another question....if the yeast are viable, why do they not ferment the beer out dry? w
Why do they quit before 1.000???

Yeast can only eat some types of sugars. It can't eat starches or other complex carbohydrates. You'll particularly hear people talk about "dextrins" which are long chain carbohydrates that add thickness or "mouthfeel" to the beer.

On a side note: The job of the "mash" is to release enzymes to convert the barley starches into sugars that the yeast can eat.
 
Yeast can only eat some types of sugars. It can't eat starches or other complex carbohydrates. You'll particularly hear people talk about "dextrins" which are long chain carbohydrates that add thickness or "mouthfeel" to the beer.

On a side note: The job of the "mash" is to release enzymes to convert the barley starches into sugars that the yeast can eat.

got it..the the residuals are unfermentable sugars...thanks.
 
Could someone explain "Overpitching", and the growth cycle. I had read in a thread about yeast washing that you should do a starter because otherwise the yeast spend too much energy just multiplying. Isn't this what yeast do to produce alcohol?
 
Could someone explain "Overpitching", and the growth cycle. I had read in a thread about yeast washing that you should do a starter because otherwise the yeast spend too much energy just multiplying. Isn't this what yeast do to produce alcohol?

Read this summary of the yeast life cycle from the BJCP Exam Study Guide and let me know if you have any questions.

When yeast are pitched into fresh wort, the overall process of fermentation can be divided into several stages, all of which are part of the life cycle. While these stages can each be described separately, the transitions between each are continuous and should not be thought of as distinct phases. Also the relative time spent in each phase depends on several factors including the composition of the wort, the environment and the amount of yeast pitched.

The first phase of the cycle is called the lag phase. During this time the yeast will adapt to the new environment they are now in and begin to make enzymes they will need to grow and ferment the wort. The yeast will be utilizing their internal reserves of energy for this purpose, which is the carbohydrate glycogen. The yeast will acclimatize itself and assess the dissolved oxygen level, the overall and relative amounts of the amino acids and the overall and relative amounts of sugars present. Some of these amino acids, small groups of amino acids called peptides, and sugars will be imported into the cell for cell division. Normally this period is very brief, but if the yeast is not healthy, this period can be very protracted, and ultimately lead to problematic fermentation (8,1).

Based on these factors, the yeast will then move into the next phase of the life cycle, the growth phase. During this time the yeast will start to divide by budding to reach the optimal density necessary for the true fermentation. If an adequate amount of healthy yeast has been pitched and the proper nutrients are present, there should only be one to three doublings of the initial innoculum. The oxygen that was used to aerate the wort is absorbed during this time to allow the yeast to generate sterols, which are key components of the cell wall (9). It has also been proposed that cold trub can provide the unsaturated fatty acids needed for sterol synthesis (10, 11). Furthermore, it has been proposed that if an adequate amount of yeast has been pitched, such that cell growth is not necessary, then the oxygenation is not necessary (9, 12). While this theory has not been completely accepted (13, 14), perhaps further research will elucidate other variables which may be involved in this phenomenon. This sterol synthesis is the default pathway used in an all malt wort; however if the wort contains greater than 0.4% glucose then this pathway will not be used and the yeast will instead ferment the glucose, even in the presence of oxygen. This effect is called glucose repression, or the Crabtree effect.

Following the growth phase, the low kraeusen phase of primary fermentation begins. During this time the yeast begins anaerobic metabolism, since all of the oxygen has now been depleted. This is characterized by a foam wreath, which has previously existed on the sides, now migrating to the center of the surface. The yeast have now completely adapted to the condition of the wort and transport of both amino acids and sugars into the cells for metabolism will be very active. During this period fusel alcohols and diacetyl can be produced. To minimize the formation of fusel alcohols, one should try to keep the temperature down, make sure that adequate dextrinous sugars are available, and minimize the amount of hot trub present in the yeast cake. To minimize the diacetyl in the finished beer, one should try to avoid the reintroduction of oxygen, excessive cooling of the fermentation in later stages and premature removal of the yeast.

At the high kraeusen stage following this, an ale yeast will have metabolized most of the sugars present in the wort. A lager yeast, on the other hand, may still be in the growth phase while also reducing the extract by four gravity points/day. Lager yeast will be metabolizing most of the sugars during the high kraeusen phase. Following this phase is the late kraeusen phase. In lager yeasts this can be very important, since it is during this time that the yeast begin to metabolize some of the fermentation by-products they had previously excreted during the low kraeusen phase. Specifically, a diacetyl rest may be performed to help with the re-absorption and subsequent reduction of the diacetyl and the related 2,3 pentanedione during this time. The temperature of the beer may be allowed to rise up to 68 °F. Generally as the extract reaches its terminal point the yeast will begin to flocculate out.
 
got it..the the residuals are unfermentable sugars...thanks.

The caveat to this is that attenuation isn't a rock solid number...with more oxygen and other nutrients, the yeast may be able to metabolize some things it was previously too sleepy to bother with.
 
HOLY COW! I thought all they did was eat sugar and make babies.
Ok, here's a few questions.
1. How do you know if your yeast is helthy? (i assume it SHOULD be if you're buying it)
2. How do you know if you're pitching enough/too much yeast?
3. How/When do you perform a diacetyl rest?
 
HOLY COW! I thought all they did was eat sugar and make babies.
Dont forget, the pee alcohol...
1. How do you know if your yeast is helthy? (i assume it SHOULD be if you're buying it)
You can proof it(most dry packs have instructions on the back) or you can make a starter.

2. How do you know if you're pitching enough/too much yeast?
http://www.mrmalty.com/calc/calc.html
3. How/When do you perform a diacetyl rest?
Thats just a fancy term for "leave the beer in the fermenter for a few extra days." The only thing you have to do is be patient:mug:
 
Dont forget, the pee alcohol...
You can proof it(most dry packs have instructions on the back) or you can make a starter.
http://www.mrmalty.com/calc/calc.html
Thats just a fancy term for "leave the beer in the fermenter for a few extra days." The only thing you have to do is be patient:mug:

We need to clarify a few things here.
1) How do you know if your yeast is healthy? Proofing is the way, but some dry yeast companies don't recommend proofing. You're essentially feeding your yeast junk food with absolutely NO nutritional value, which means they have to use their internal nutrition stores to process it. In effect, you just weakened your yeast in order to see how strong it is. Oops: Catch-22. First step is always to get your yeast from a good source that moves a lot of product (so its fresh). If it seems old, do a starter...dme is full of yummy nutrients, so a starter doesn't deplete the yeast.

2) How do you know how much to pitch? Yeah, use Mr. Malty. But, in general, a vial or pouch of liquid is not enough for a normal beer. A dry pack is...if properly rehydrated.

3) Diacetyl rest is not really just a fancy term for leaving the beer on the yeast a little longer, its a fancy term for raising the temp of your fermentation a bit. This is mostly something that people do with lagers, so if you're just doing ales, I wouldn't even worry about it. But, if you're interested in lagers, here's what John Palmer says in his lager section of How to Brew:
"To remove any diacetyl that may be present after primary fermentation, a diacetyl rest may be used. This rest at the end of primary fermentation consists of raising the temperature of the beer to 55-60 °F for 24 - 48 hours before cooling it down for the lagering period. This makes the yeast more active and allows them to eat up the diacetyl before downshifting into lagering mode."


I'm splitting hairs here a bit...the person above is right that diacetyl usually only becomes a problem if you take the beer off the yeast too quickly. (Btw, diacetyl (like many off-flavors) is an intermediary compound released during fermentation.)
 
HOLY COW! I thought all they did was eat sugar and make babies.

Yeah...the key thing to remember is that yeast are both aerobic and anaerobic. Kinda weird if you think about it...sorta like being amphibious...

Anyway.
They start aerobic and make babies.
When they're done making babies they start making beer.

It's the circle of life!
 
Thanks for all the great info. I should have bought it soon, but I do have Palmer's book on order from Amazon as no one in town caries it. God, we need a good book store in the wonderful city of Decatur.
FYI incase anyone is looking for some good How-to/Beer-Brew books, Amazon has a special...spend $25 get free shipping. I ordered via Amazon, cause i'm only spending $7 more, and getting two books.
 
Apologies beforehand, but I just had to throw this in based on your user-name and the topic title:

"Qu'ils mangent de la brioche"
 
Ah, well I believe it reads, "Let them eat cake!" as was supposedly stated by Marie Antoinette.

Let them eat yeast cake??

Doesn't sound so good though, hehe.
 
one version is like brick-pack mexican marijuana... you get a huge block of yeasties that you crumble apart.

another is the flocculated yeasties in a fermentation vessel.

I'm confused...can I smoke this type of yeast??:p Also...how do you know so much about marijuana?? :D
 
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