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G'day all.
I have been re-using yeast cake for ages no-probs. Due to a shortage of beer and short-sighted planning I had to top crop earlier today. And a lack of bottled brew which is the real problem
I sanitised, scooped maybe half a cup of krausen from a brew and pitched straight into next brew.
Will this work?
Or should I anticipate having to pitch some yeastcake in a few days?
I need beer fast as supplies are critical, CRITICAL i tell you.

Hmmm don't know Rotten as I have always built it up.
Probably be fine, maybe just a long lag time.....christ why did I do all this typing when I haven't a clue!!

I would say that top-cropping is preferable to pitching on/from a previous yeast cake, with the caveat being that your initial source of yeast was optimal and not infected/stressed/mutated.I have only done this a couple of times and have been happy each time. As far as I know, the theory is that, for a true top-cropping yeast, the healthiest and most active will rise to the top of the fermenting wort. Traditional ale breweries in England top-crop.

I have also heard advice from the brewer at a well-known micro to:

1) at the beginning stages of fermentation, skim off the first rise of yeast (which will also carry hop and trub residue) and discard. 2) Crop the next, more pure, rise of yeast and pitch onto the next batch.

I have no idea how to guage cell-count by this method, but I reckon a couple of cup-fulls of foamy yeast would deliver.

edit: Short answer: I reckon in a few days you will know whether or not the yeast has taken off.

What yeast did you top crop?

I do this regularly for true top croppers like WY1469, 1187, 1026.

1/2 cup might be enough but i normally collect all of the krausen and then pitch the whole lot. I sometimes store it for a few weeks before pitching but find that the lag time is greatly reduced compared to using yeastcake.

drsmurto wrote:What yeast did you top crop?

US-05

I'm pumping out APA's at the moment to build up stocks.
Question answered itself, krausen this morning, high krausen this arvo.
Thanks guys.

US05 is a very poor top cropper.

If i was a betting man I'd put a few dollars on acetaldehyde from under pitching. Smells like green apples.

It will still ferment and will look like everything is going along smoothly, you may well even hit your expected FG.

You might get lucky but I wouldn't be top cropping US05. Next time you plan on doing so let it settle out after top cropping. When doing so with WY1469 and other true top croppers you'll get more than 100mL of pure yeast. With US05 you are lucky to get 10mL. I tried and discovered why it's not a good idea.

There is a different, fruity smell, not infection. Will it still be drinkable?

Maybe. Whilst in theory you have underpitched you might get lucky.

Worse case scenario, dry hop it with twice as much as usual!

Just to offer another perspective, I often top crop US-05 with very good results. OK you won't get anywhere near the same amount of yeast you would from genuine croppers, but there's usually more than enough if you pick the right day to crop (and for me, that's after skimming the scum off but before the yeast starts falling back). Ideally, you need around 50ml of thick paste (after it has settled out well) for a standard size brew at around 1.050 OG. Must admit, there have been a couple of occasions where I missed the best time to crop and wouldn't have ended up with enough yeast.

Cheers, Ed

I thought I would post the recipe as I have a question about dry hopping, so

Simarillo (American Pale Ale)
Original Gravity (OG): 1.053 (°P): 13.1
Colour (SRM): 5.6 (EBC): 11.0
Bitterness (IBU): 48.7 (Average)
66.66% Pale Malt
33.34% Munich I
1 g/L Simcoe (12.2% Alpha) @ 60 Minutes (Boil)
1 g/L Amarillo (8.6% Alpha) @ 20 Minutes (Boil)
1 g/L Amarillo (8.6% Alpha) @ 5 Minutes (Boil)
Single step Infusion at 66°C for 90 Minutes. Boil for 90 Minutes
Fermented at 20°C with Safale US-05
Recipe Generated with BrewMate

This was no chilled for 3 days before putting in fermentor and pitching US-05 top cropped yeast.
I have never dry hopped before.
I would think 1gl - 20gm would be enough, especially because it's amarillo. Or maybe 1.5 gl - 30gm.
The smell described is gone, will taste it when I rack but I reckon it will be fine.
Thoughts anyone

Depends how you feel about Amarillo, I suppose - looks like your recipe could support either. If you're unsure, 1g/l will be noticeable.

I racked this today. FG was supposed to be 1013, ended up with 1009, so not too bad I'd say. The taste test went well too, there was no banana, apple, acidic or anything else that shouldn't have been there. It was smooth although I could pick up the bitterness from the Simcoe, but that's why I like it.
I dry hopped with 20 gm Amarillo and will cc for a few days before bottling. Let you know how the real taste test goes.

P.S. I think I got lucky, maybe just got the timing right. Thanks for advice as always