The_blue wrote:New hijack time
I'm thinking i have a grasp but need my summary peer reviewing
So what i gather....
1.So beer is better than water (durr!
)
Green beer is at least an order of magnitude better than water when it comes to storing a yeast crop. Boiled water is not sterile. Boiling does not kills spores. Replacing the green beer with boiled water removes the protective force field that the culture built for itself.
2.Rack the beer and hold a little back.
Correct
3.Swirl it all together to make a yeasty soup.
Correct
4.add to a clean jar and allow the trub/dead yeast to settle out.
If using a transparent or translucent fermentation vessel, this step can be skipped because one can wait until the lion's share of break and other organic material settles before decanting the cleanest thin slurry from one's fermentation vessel.
5.Keep the milky liquid above the trub along with the beer it's suspended in.
One does not really want to wait until all of the break and other organic matter has settled out. Waiting too long will result in one cropping the least flocculent cells, which over time can result in a loss of flocculence.
6. this will settle out to beer and creamy yeast into layers
In reality, one will end up with four distinct layers. A very thin dark layer that is mostly organic material like hop resins that have been scrubbed from the wort (this layer may not be present), a mixed break/yeast layer that is roughly 60% yeast, a thin lighter colored layer or the least flocculent yeast cells, and the supernatant (the clear beer that lies above the solids). Far too many home brewers get hung up on having a completely organic matter/break-free crop. Yeast does not need to be kept physically clean. It needs to be kept biologically clean. The yeast harvested from the middle of the cone of a conical is not 100% break and organic matter free. The crops taken from conical fermentation vessels are typically 40 to 60% yeast solids. The remaining fraction is break/ organic matter.
7.Keep in the fridge till used inc the beer.
Cropping is not a long-term storage technique. I have found that a crop can usually be stored up to a month without having to feed it or make a starter. After that, viability drops off fairly quickly. Granted, a large old crop will usually get the job done, but one does not really want to pitch a large number of old yeast cells that have been in a quiescent state for an extended period of time into a batch of beer.
8. pour off the beer and pitch.
Yes, but with the caveat above.
A technique with which I have been experimenting lately is double-dropping starters that were made from non-fed crops that have been in storage for around eight weeks. The double-drop fermentation system was developed as a way to separate young fermenting beer from break and dead yeast cells. It consists of a two-tier brew house with a large primary fermentation vessel where the wort is pitched and held for about 12 to 18 hours before being dropped into smaller vessels called "pontos." Double dropping gets the beer off of the break and dead yeast cells as well as provides additional aeration. What I am doing is starting 50ml to 75ml of thick slurry in 1L of 10% w/v (1.040) wort using a 5L media bottle and my shaken, not stirred starter method (a.k.a. the James Bond Method). I then carefully transfer the liquid fraction of the starter to a 2L Erlenmeyer flask as soon as signs of low krausen appear. This method allows me to decant the viable cells that are in suspension while leaving the break and non-viable cells in the media bottle. I pitched a starter made from an old crop using this method into 21L of 1.064 wort at around 18:00 on Saturday evening, and had active fermentation, complete with a 1" of krausen, when I checked on the fermentation at around 7:00 on Sunday morning, which tells me that visible signs of fermentation appeared in less than twelve hours. This outcome matches that of recently cropped first-generation crop.
