taking yeast off the top

[matthewdick23]

gonna brew on sat- doing a starter of 007 from some I've washed.  Only have enough stuff to make about 1L of a starter.

However, I have a brew fermenting now- Am I right in thinking I can steal the stuff off the top of this bubbling beer?

Is it possible to take enough off to not need a starter for my brew on sat? how much would I need? 30 L of 1.040 og

thanks

matthew

[Dr Jacoby]

Top cropping is an excellent way to re-use yeast and there would be more than enough available on a standard batch to get a second batch going. Here's one popular system for doing it in a sanitary way.

[matthewdick23]

thx guys

hmm that article doesn't really talk about amounts.

I'll take a grav reading of my ferm beer when im home- have two thoughts

1- I have two bottles of washed 007 yeast- mite combine them in a 1 L starter (wjhich is as big a starter as i can make atm). then throw in some top cropped yeast too into the starter.

2- depending on the reading of the fermenting beer, it might be done by sat (it was a low grav beer and only about 7 L or so I think). so might just bottle on sat if readings are good and throw new batch on top of old trub


thoughts?

[Dr Jacoby]

I'll dig out my copy of Chris White's yeast book to give you a better idea of the amount needed. From memory, top-cropped yeast is very potent so you don't actually need that much, but I can't give you a definite figure. I'll try to get back to you this evening if nobody else has the info.

[matthewdick23]

thx

[Dr Jacoby]

Ok, I had a look at the Yeast book and no specific amount is mentioned. But I think this is because there are quite a few variables. You need to skim at the right time (about 2-4 days into the fermentation), and depending on the strain (i.e. how flocculent it is - the more flocculent the strain the more will rise to the top during high fermentation) there may not be enough to work with. Judging by some sites I came across, it seems that if there is a thick foam on top, and if you manage to skim most of it, you will have plenty of yeast to start a new batch. This yeast will also be at the height of its vitality and health. Just be careful about sanitation.

[Hop Bomb]

Im trying this out now on the RIS for the barrel. Pic from this morning. I pitched the starter at 6pm Sunday.
When I stop collecting tomorrow can I just swirl in some boiled & cooled water & pour the stuff into a sterile
kilner jar & save for use again? Or does it have to be used immediately?

[Dr Jacoby]

That looks great! You can store the yeast in the fridge for a couple of weeks at more or less full health but it will start to go down hill after that (how quickly depends on temp, how well the yeast was treated before pitching etc.)

The only thing I'd say is that because the yeast was made to work very hard in a huge beer, it mightn't be in the best of condition. The problem is not so much that it had to survive in a very high alcohol environment but rather that it probably went into overdrive consuming all the sugars in your wort. I'm sure it would be fine to use again but I wouldn't risk using it a third or fourth time.

[Hop Bomb]

Maybe I wont bother this time so. We'll call this a trial run. Thanks!