When to harvest ale yeast from conical fermenter?

[Smiffy]

Now that I have a conical fermenter and will be able to drain yeast at any time, the question is which yeast to save?

My thinking is that the yeast which settles to the bottom early on is not the yeast which is working well, and that the yeast which is working well (top fermenting ale yeast) won't settle until the fermentation is coming to an end.

So, can anyone tell me which day's yeast is the best stuff to save for the next brew?

[Smiffy]

That begs the question, when should it be drained prior to collecting?

I'm assuming that any sediment present while fermentation is vigorous is dead and should be thrown away.

I have saved three lots from the current brew:

after 2 days (drained while fermentation was still going)

after 4 days (when fermentation had stopped, possibly within the 8-12 hours suggested)

after 6 days

I will try a small sample of each in a "starter" and see if there is any difference in how quickly they start and how vigorous they get.

[Grant R Baker]

If your recovering yeast from the cake (or drained cake) there should be some alive yeast left in it.

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Much of what I have read on this subject suggests collecting yeast from the cake after racking to secondary or when draining the yeast cake from the conical.

Try adding some of the yeast cake to a warm glass of water with sugar in it and see if there is a reaction. Should be. (Yeast reaction usually appears as a foam on top of the water after an hour or two, but will be obvious after 12hours).

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I'm just gearing up for this myself and as usual have over-read on the subject.

[Smiffy]

My test samples all fermented. All three resulted in a similar taste, the same final gravity and produced a similar amount of sediment. The differences were, sample one didn't produce as much yeast head and in sample three the sediment was more easily disturbed. So it seems that the best yeast is number two, collected soon after fermentation had completed. But the differences are small. Perhaps "selective breeding" will have more benefit the more times the yeast is re-used.

[JackoNZ]

Good experiment Smiffy, having just purchased a stainless conical that's good info to have at hand. 

[Liam Callaghan]

Are you washing it Smiffy when you have collected it?  Or just collecting from the bottom of the fermentor in a sterilised jar and repitching on your nxt brew day?

 

No experience in this at all so excuse my ignorance if these are simple questions...

[Smiffy]

I have never tried washing it. I go with the idea that yeast is happy in beer, so store it in beer. So, yes, I put it in a sterilized jar, and put it in the fridge. For the next brew I take a jug of wort and put a couple of tablespoons of the yeast sludge in it, an stir gently until it has broken up, then add to the rest of the wort. The longer the yeast has been in the fridge, the longer it takes to become active again. Fresh from one brew straight into another and the air-lock is bubbling away in minutes, yeast that's been in the fridge for a couple of months takes hours before the air-lock starts to bubble.

One good piece of advice I read is to smell and taste it when it is fresh, and again before you use it, so you can tell if it has gone off.

The only problem I have had was with a fourth hand sample which caused the brew to be very-very slow to clear.

Collecting yeast at the right time from the conical, should mean that will never happen again.

[Liam Callaghan]

That was good timing, logged on as you replied :p

I'm just going through my first sessions cultivating yeast onto slants and starters, pretty happy with that I think, just need some practical experience.  I still wasn't sure how to handle the slurry though and if washing was required. 

Easy enough to take a sample and store it in cold sterilised wort in the fridge, label it with the generation number and restart when you need it. 

Do you use fresh sterilised wort or beer from the batch it was grown in?

[Smiffy]

I don't put it IN beer to store it, just leave it as it is, unwashed, with some of the beer it has just made.

To re-use, I mix it with some of the wort of the new brew, but this is purely to get the yeast to separate more easily. After it has been stored it settles into a very solid, almost rubbery, mass. If I just put that in the fermenter, and didn't stir enough, it would just sit there as a lump for a while, stirring it in a jug allows me to see when the lump is all broken up.

[Liam Callaghan]

Ah now I get it!  I think the sound of that penny dropping must have gone right around the office. 

Clear as a bell now mate, thanks for that!

[Hillman]

I had a look through that book I mentioned earlier. They didn't mention cropping on different occasions. Instead, they just recommend that you discard the first third, and the last third on the one occasion you do crop. The first third will be darker, and have flecks of trub and hop matter in it, while the second third will have a creamy consistency and be much whiter. The final third is low-flocculating and excessively attenuative. I guess you have to know when to stop by practice.

This seems to fit with your experience, seeing as the second crop was the best sample. The other alternative is to just dump your new wort on the yeast that's already in there. We did that last time we brewed. Saves on sanitizing and goes like a rocket, but of course it means you need a pretty rigorous brewing schedule.

[Smiffy]

The reason I did it that way was primarily because my local professional brewer told me they drain the yeast every day. At the time I didn't think to ask which was the best to save as I didn't expect to have a conical fermenter of my own. A second reason was to better understand the quantities of yeast settling out at different phases.

Leaving the yeast in the fermenter will certainly work once, but I wouldn't like to try it more than that as the fermenter will still contain second "generation" low-flocculating yeast (twice as bad?) and the dried on yeast "tide-mark" will start to add yeasty tastes and there's possible contamination.

With a conical, it is going to be easier to collect the middle third by timing, so I'll continue to do that.

[Hillman]

Yeah, the instructions on my conical said to crop over the course of a few days. I was really just reporting on what this book had to say. I think I'm going to go with what this book says in the future -- I'm pretty convinced that a bit of trub won't hurt, one crop seems like less work, and it was written by the boss of White Labs, which is good enough for me.