Yeast Propagation

[RoboBrewBot5000]

Hi, I need some advice. I am attempting to propogate yeast from a single bottle of sierra nevada. I have never done this before. After several step ups starting at 100ml now have a conical with 1.2L in it. At this point in time this has been on a stir plate more or less constantly since Sunday last week. (7 days). I now have a very active flask - see pic.

Question is: what next - should this have enough yeast in it to ferment a 23L batch of say, 5% IPA do you reckon? Would you let the krausen fall and the cold crash, decant and pitch?

I am trying to plan my brew day!

 

[dmtaylor]

Yes, looks like a good quality step-up with sufficient yeast for 23L. No need to crash and decant. Just pitch the entire thing.

 

[DocAnna]

Personally I'd have a taste first to make sure you don't have a mixed bacteria and yeast culture if it's taken that long on the stir plate. Either that or if you want to be technical, check the pH. The last thing you want to do is put a mixed culture into your volume of wort. I'd have a couple of concerns as I'd have expected peak activity by about 2 to 3 days and for it to have died down since on a stir plate. Ongoing such vigorous activity would make me a wee bit nervous. However if it tastes ok and not acidic then probably fine.

I always chill and decant but that's because I keep the supernatant to settle out and keep for next time.

 

[The Baron]

I am with Anna it is possible if its taken that long it may have got contaminated with another strain.
So taste it to see if it is ok is my advice

 

[RoboBrewBot5000]

All: thanks, to clarify, it's only been on the stir plate since the last step up for 36 hours (7 days total including all steps). I decided to crash and will use in brew either later or tomorow.

Will advise. I'm redoing an American IPA recipe I've done previously which was my bests to date hoping the yeast really helps with v2.

 

[RoomWithABrew]

Seems like a good plan, if you have time to crash it and then can pour off that oxidised wort ( beer).
Still worth tasting that though if it's nasty look again.
If you can save some of the yeast in a sterile container your next starter will be easier or top crop the ferment.

 

[RoboBrewBot5000]

Update...its taken 4 days to get from 1051 down to 1015...I mashed high so I'm hoping this is terminal gravity. No weird smells or tastes...I think this may have worked out!!! Will post a final update when I've had a chance to sample post bottling...

 

[RoboBrewBot5000]

Update...its taken 4 days to get from 1051 down to 1015...I mashed high so I'm hoping this is terminal gravity. No weird smells or tastes...I think this may have worked out!!! Will post a final update when I've had a chance to sample post bottling...

Further update: finished beer was good. Not exceptional, but more than drinkable (probably my choice of hops more than anytbing else). Have since harvested and reused the yeast from this brew for a cider and another pale Ale. All of which have turned out well. Looking forward to the next brew with this yeast which should be (fingers crossed) even better.