How long can I keep a yeast cake in a carboy with no beer on top?

Alright, I wash yeast/make starters all the time, but I'm feeling lazy and I really want to use the S-05 I've got in the carboy. I kegged a batch of Bm's Cream Ale today and I didn't throw the cake away. I just put the airlock back on top of the carboy and it's sitting in the closet at a cool 60* F. I've let yeast cakes sit in the carboy for a day or so before washing it, but I've never let one sit in the carboy for a week (when I plan to brew my next batch). Do you guys think I'll be ok doing this or should I just pitch a new packet of S-05?

Thanks,
J

Alright, I pretty much think that I should have known this. I did more searching and I found that a lot of people have done so as long as there is a bit of brew on top (which there is on mine). I'm just going to be lazy and go for it.

J

let me know what happens I got some thats been sitting for a while I want to use...

How did this work? I have one that I left about .5" of beer on top of about 2 weeks ago (planned to use sooner, but got lazy about brewing).

You probably shouldn't be pitching onto the whole yeast cake anyway--it's badly overpitching. You'll still get beer but why not take the time to make it as well as you can. Pour your yeast cake from the carboy into a santized jar of the proper size (you don't need much; like I recently pitched 100 ml of slurry into a new batch and you rarely need more than a cup) then store it in the fridge. Clean your carboy and properly sanitize it. Then re-pitch your yeast into well-aerated wort.

Yeah, i was planning to wash it before re-using it tomorrow, just didn't know if the cake was still good. It has been 18 days since I racked off of it, and it has been at room temp (68-70). I had room in the fermentation chamber to store it, but it was in a side room that I never go in, so it slipped my mind.

On a side--note, I was going to use it on a 1.094 OG IIPA if it is still good.

If you are going to just repitch the slurry I wouldn't personally bother rinsing it. Use the pitching rate calculator at www.mrmalty.com to decide how much slurry. The long lag between harvesting & repitching will affect viability.

I like the idea of repitching slurry into a big beer so you are sure to have a lot of cells, but that is predicated on the assumption that your yeast has been cared for carefully. Tough one--you might need to use most or all of your slurry to get to the right cell count given how long it has been since you racked.

After a week? I tried that myself but your taking a big chance on making sour beer. I repitched after a day but not a week. The yeast didn't look to healthy. If it's so5 I would just pitch a new pack and dump the old stuff. Next time your feeling lazy just throw it in a Ziploc bag and put it in the fridg. Till you are ready to use it. Just my 2 cents.

I wouldn't mind making a sour beer (doing one today), but I don't really want the IIPA to be sour. I think I will just dump it and use some new yeast this time, then try not to be lazy next time I have a cake. Thanks for the input everyone.

Bringing this one back to life. I've reused a yeast cake within 48 hours and had no problem.

As for overpitching, the Brulosopher has done an xbmt in which he pitched 4 dry packets vs 1 dry packet. The panel could not tell the difference.