Do I Need A New 1st Gen Yeast?

[Trent]

Gday all
I have a habit of using yeast that I have stored, like we all do, and I am genberally pretty careful not to let them go over a few generations old. I AM concerned, however, after hearing something on the brewing network, or reading somewhere that if you dont give your 1st gen yeast heaps of O2 and plenty of yeast nutrient, no matter how well you look after the ensuing generations, they wont perform as well as they are supposed to. I used to make a 2L starter from my smackpack, pitch that, and then harvest yeast from there. I now use nutrient, and will be using the Ross method of splitting the yeast pack. Now, finally, to my question. I used 2nd or 3rd gen 1056 to pitch into an APA 8 days ago, aerated really well and used nutrient. The OG was 1053, and it was blazing withing 12 hours, and had blown the airlock after 24, so I just put on a blowoff tube, and let it go. It has been bubbling every 2-3 seconds, and as it is a glass carboy, I can see trub and yeast and stuff flying around the brew, it looks pretty busy. Problem is, I got impatient, and the sg right now is only 1030, after 8 days. I am pretty sure I need some new yeast, but do you think that it will ever come good and actually finish? It tastes bloody sensational, and I dont wanna lose it, so is there any negative effects from leaving it ferment for over 2 weeks (cause thats what it looks like it will need)
All the best
Trent
EDIT - It has been fermenting at between 20 and 22C

 

[Airgead]

Gday all
I have a habit of using yeast that I have stored, like we all do, and I am genberally pretty careful not to let them go over a few generations old. I AM concerned, however, after hearing something on the brewing network, or reading somewhere that if you dont give your 1st gen yeast heaps of O2 and plenty of yeast nutrient, no matter how well you look after the ensuing generations, they wont perform as well as they are supposed to.

trent

Thats true. To a point anyway. The key is to make sure your yeast is healthy and not stressed. Stressed yeast are more likely to mutate and develop undesirable characteristics. they caln also have weaker/not as well formed cell walls which makes division and fermentation more difficult. If your yeast stresses, you shouldn't re-pitch. Even healthy yeast degrades over sucessive generations so there is a point where you need to get a new first gen culture (6 generations or thereabouts is the general rule).

. Problem is, I got impatient, and the sg right now is only 1030, after 8 days. I am pretty sure I need some new yeast, but do you think that it will ever come good and actually finish? It tastes bloody sensational, and I dont wanna lose it, so is there any negative effects from leaving it ferment for over 2 weeks (cause thats what it looks like it will need)
All the best
Trent
EDIT - It has been fermenting at between 20 and 22C

[post="127311"][/post]​

There's a one word answer to this one - Depends. I'd say it will probably just ferment really slowly and end up OK. Maybe a few points higher than you wanted but othewise fine. The yeast could have decided to drop out early so rousing them might help kick things on again. I don't re-pitch (I grow mine on slants) but I have heard that early floculation is a fairly common problem in re-pitched yeasts. Especialy ones that have been previously stressed. From what I have heard, the stress (and the stress imparted by keeping a slurry for any significant period of time) sends them into survival mode so they gorge quickly to build up reserves then drop out and hibernate.

I'd try rousing the yeast and see what happens. or you could just pitch some fresh yeast. At this stage just a cheap dry yeast to finish things off should work OK as the flavour profile should have already been imparted by the original yeast.

A long fermenmtation shouldn't hurt. After all barley wines ferment for weeks, grape wines ferment for months and I've had meads fermenting for nearly a year.

Cheers
Dave

 

[Stuster]

Since you can see activity and the gravity is dropping, I'd be surprised if it doesn't get there in the end. You say you used 2nd or 3rd gen yeast. Did you make up a starter and if so how big? How long had the yeast been in storage. Could it have been damaged in the fridge, perhaps got frozen. I have had that happen to some yeasts that got too close to the back. Anyway, there's absolutely no problem with letting it run its course for 2-3 weeks. So relax, etc etc.