what's a yeast cake

I've read some posts that mention yeast cake, and a few of them gave me the idea that's is the yeast that has settled out during fermentation.

How is that different from trub, and what is ment by pitching onto a cake?

Thanks for the explainations!

Its not different. Same thing.

It's the stuff left at the bottom of the fermenter.

Pitching onto it means draining the old brew and putting a new unfermented brew into it and not pitching new yeast.

The difference between trub and yeast cake is trub includes hot and cold break, while a yeast cake is made of yeast. In most cases they are one and the same, but when you pitch on a yeast cake you want it to have as little trub as possible. That is why people use secondary yeast cakes to pitch and not primary. But if you chill in a whirlpool and leave your break behind you don't even need to worry about secondaries.

Ah, this all makes so much sense now!

So is when you pitch onto the yeast cake, do you also pitch fresh yeast?

Also I'm sure you dont want to wait too long to pitch the next batch onto it and all that right?

You don't pitch fresh yeast- there is lots of yeast in there and in fact you will have a pretty fast fermentation due to all the yeast already there. It helps to stretch your yeast dollars if you're using an expensive liquid yeast.

If you are pitching on the cake, you want to remove the beer and pitch the next batch onto it. If it's going to be a while before you do this, it's usually best to wash that yeast and store it in the fridge. (do a search for "yeast washing" and you'll see how that works)

I've looked into washing yeast and decided i'm not ready to try that yet .

Dycokac said:

I've looked into washing yeast and decided i'm not ready to try that yet .

Click to expand...

All you need is 2 - 1 gal jugs...

From what I have read & understand, trub is, like other said: hot & cold break. The break is composed of proteins that "curdle" during the boil (just like the protein in an egg when it is poached). Of course this stuff (trub) settles out along with the yeast - thus forming the cake. I guess you could say the yeast cake is a homogeneous mixture composed of trub and yeast. Correct me if I'm wrong guys.

is the goal of washing a yeast cake to separate the rest of the other beer residue from a pure yeast settlement?