Yeast harvesting terminology and jar question

[kojinakata]

Hi everyone,
I am a little confused about some terms when I was researching about yeast harvesting. The first category being yeast slurry, yeast cake, trub. What do these three mean?

Another thing I cannot grasp is the difference between yeast harvesting and washing? Do these terms differ in someway or they basicly mean the same thing?

Also I came across the term, yeast farming. What is it exactly?

My last question is: Can I use peanut butter glass jars with screw on plastic caps as my container after harvesting the yeast? I am looking for alternatives to mason jar as I couldn't find them here where I live in Finland.

Thanks in advance. Any helps is appreciated.

 

[bzwyatt]

Trub is the solid stuff at the bottom of the fermentor, so it has yeast, hop and grain debris, anthing else you made beer with.
Normally you don't want anything except the yeast out of the trub, so you wash it. There are different methods of doing it, but for many homebrewers, it is just using sanitary water to separate the yeast from the other stuff, and it is called 'rinsing' if you want to be more technical about it.
Slurry is the yeast at the bottom of a jar when you've either made a starter, or you've rinsed yeast. There is still yeast suspended in the liquid, so the slurry doesn't have all the yeast in the jar, but some people also don't like pitching the beer in a starter, just the yeast. They only pitch the slurry.

Any glass jar is good. I wouldn't use plastic - it absorbs flavors/smells, and I wouldn't want to worry that my yeast might pass on flavor of pickles or peanut butter to my beer.

 

[LabRatBrewer]

In my mind Yeast Slurry and Yeast Cake are the same. Trub is the fallen spent hops and break material. It sits on, and is mixed with the yeast cake (hence the desire to wash the yeast - to separate it from the trub).

Yeast Farming is keeping several strains, some times on slants, sometimes frozen for future use.

Harvesting is an encompassing word that would include yeast washing, yeast rinsing, top croping or any other method of reusing yeast.

Technically, unless your using an acid, most of us are actually yeast rinsing rather than yeast washing, but the term yeast washing is being blurred by common usage.

I think the peanut butter jar would work.

 

[KepowOb]

There is a forum member (sorry, I forget who), who has some posts over in the yeast & fermentation sub-forum talking about how we shouldn't be washing our yeast, and he has some info to back it up. Harvesting it is fine, but he talks about how there is a lot of stuff in the trub that helps the yeast, rather than hurts it, for the most part, and how washing is actually detrimental. I'm taking a 2-minute break at work right now, but I'll try to find more info when I've got a bit more time (or hopefully someone who knows more about it chimes).