Harvested Yeast Over a Month Old??

[brew captain]

I have some 001 that was harvested on 12-15-07. It had just fermented a hopped up American Red and an American Brown. I am brewing a robust porter tomorrow, but sitting here looking at that month old yeast with some apprehension. I have some Safale 56 that I wanted to try too, but hell free yeast is free yeast...

So, what is the oldest you would let some slurry get before you wouldn't take a chance using it?


Cheers!

[Rezzin]

I'd make a starter. If it doesn't turn out well you can pitch the Safale 56.

I just checked the calculator on MrMalty.com and if I did things right, a month old yeast slurry is only 50% viable. You would need to pitch about a cup and a half of slurry to get enough yeast to properly ferment that beer.

I would try to use it but I only brew 5 gallon batches.

[backyard brewer]

I've used very old slurries without trouble. But, I do pitch a pint of fresh wort (canned) onto it and make sure there is good activity. I also store the yeast near freezing as well.

Really, though, I would recommend getting a hold of two vials of White Lbas British Ale yeast, WLP005. I relaly like the way this yeast acents the malt, it is a very good choice in a porter, but that's just my experience and opinion.

[brew captain]

So it seems it is more a vitality issue versus a contamination concern (from the autolysis providing nutrient for latent bacteria). I have 4000ml of slurry so I can easily bump up how much I pitch. It looks like I have to cancel my brew today so another week will have to go by before I can use the 001!!

I now believe it will be fine. I keep it pretty damn clean. I will post up how it goes in a couple of weeks...


Cheers!

[brew captain]

Derrin - I have some Safale S-04 that I may pitch in one half of the batch to get the English nuances going. I am using the last Eroica hops on earth and whole Willamette for the finish so this could definitely go both ways.

Cheers!