0% Viability, lets find out.

[Beer-lord]

Jeff, how did things work out?
I've been reading about people using old yeast (1 year to 2 years old) and there's a large group that thinks even if it gives you a nice starter, that doesn't mean the yeast won't give the beer an off taste.
So, my question would be, why? If there are enough cells to ferment the beer from an old starter, why/how can that affect the taste? I wouldn't think the cells would be stressed much if they took off in the starter properly. One poster mentions "performance changes".
My thoughts are, my old yeast was not washed, was saved from a fresh yeast starter and sat in a sterile jar in the fridge for 10 1/2 months, and looks fine (I'll smell it when I make a starter tonite or tomorrow) so I think I'm good.

Upon further review, I am not sure I really have enough WLP090 so I may just throw in the last of my Hansen/001 blend that's a month old. That will insure a healthier starter and to hell with the naysayers!

[Inkleg]

It's in the fridge cold crashing. Enough yeast to ferment anything I pitch it in. I fact it threw the stir bar during some point.

I'm curious about these people that "think" older yeast gives an off flavor. Is this something they have tried or just something they "think" will happen. What about this thread on slanting yeast? Seems to be no off flavors from long storage this way and the yeast has to be built up through many stages to reach pitching numbers. I "think" some people look for something to blame as to why their beer tastes off when it was their bad prep work or sanatation that caused it. Whether it was during the yeast making/storage stage or on brew day. This is a hobby to me and it's fun to try different things and see how it goes.

My friend that owns the LHBS has been making step starters from expired yeast that didn't sell for some time now. I know he's made a tasty pale ale with a 18 month old yeast he found in the back of the fridge.

[Inkleg]

I agree with you that farmed yeast is the way to grow and store it. Supper easy and great results. Now that I think about it there are two more jars of that 1056 in the fridge with the same date on it. I'd guess that I made a 2L starter and split it between 4 pint jars. Y'all remind me a year from now and I'll make a starter from 3 year old yeast and brew the same recipe.

[Beer-lord]

Well, I don't think 10 1/2 month old yeast is pushing it much if at all. My LHBS has offered me expired yeast and I've used it with no problems. In fact, I'm going there next week and looking for a deal on some more.
http://webcache.googleusercontent.com/s ... clnk&gl=us

[mashani]

Strains can change/mutate over many generations. That might mean they produce different flavors (esters/phenols). Unlikely that this would "ruin" a beer however, any change that would do this is likely unviable and would be outcompeted by better/healthy yeast... so the reality is that maybe it's just a little bit different. If a little bit different "ruins" a beer for you then your too picky I think.

An example would be if you got a bottle of say St. Bernardus Abt 12 and a bottle of Westvleteren 12. They are the same recipe. They are made 5 miles apart. The yeast strain we call 3787 / Trappist High Gravity is derived from Westmalle, which is where they both got their original strain. But once they separated operationally, they both have been maintaining their own culture of the yeast over the years, and the strains are now slightly different, as they are both slightly different from the original Westmalle strain, as 3787 is slightly different then all of them. They are all very similar, but if you were to taste identical beers with each strain you would notice subtle differences.

That said, I can tell you that one way to revive an old yeast strain that is starting to mutate/produce different flavors is to build up a bunch of small stepped up starters from samples of the strain and brew a bunch of small simple identical beers without any hop flavor/aroma with them, so all you taste is what the yeast makes. In some starters more of a mutation might exist and potentially dominate (if the mutations are even viable, if not they will just get dominated by other more "normal" yeast), in others more cells of a less mutated/original variety might exist and potentially dominate. You just pick the batch of beer that you like the best out of that set, wash the yeast, repeat this process if you like until you have a beer that tastes exactly as you like from a yeast perspective, and call that your new good strain. (May or may not be identical to the original, but does it matter if it makes good beer?). Old isn't the issue, just if a mutation over generations has started to change the flavor. But you can "undo" this, or "use it to your advantage" by doing what I described.

If you have access to fancy scientific equipment you can try to isolate and separate noticeably different cells and then experiment with them, but nobody had that back in the day. What I describe above works as long as you have time to brew.

[Dawg LB Steve]

Pretty much isn't this how say White Labs, etc.. keep producing a strain of yeast?
They are not mutating generations as in washed yeast they are propagating from a "first generation" so to say.

[Beer-lord]

I guess I can agree that an older yeast, even if farmed from a fresh vial but is then 'restarted', could possibly cause some minor taste variances due to weak cells reproducing. But, my thoughts are that those differences won't likely make a noticeable difference in my beer. And, though stepping up an old yeast make put less stress on the yeast, isn't there a chance going from jar to starter then to another starter that you contaminate it?
Of course, I could split the difference and instead of stepping up with a 1.020 starter or making a 1.040 starter I could just make more of a 1.030 starter and decant and pitch. I like my options.
Bottom line for me, I don't worry about things like that. It wouldn't make this hobby fun if I stressed over yeast stressing. (I made a funny).

[Inkleg]

Pretty much isn't this how say White Labs, etc.. keep producing a strain of yeast?
They are not mutating generations as in washed yeast they are propagating from a "first generation" so to say.

Good point Steve.

[Beer-lord]

Well, nothing goes as planned. I started the starter to boil, took out the 2 jars of WLP090 and decanted the jars and left just enough beer on top to swirl it good but I didn't like what I saw. One had too mark dark, almost black coating on top and didn't smell as 'beery' as these jars normally do. The second jar was slightly better but I decided to chuck it. It appeared the jars were sealed fine and I didn't smell anything sour, just not what I am use to.
So, I am using the last 2 jars of my Hansen/001 blend from 9/16 and I should have enough to save some for another brew.
No biggie, while I like 090, its not my favorite but it's move on and brew time.
Thanks for all the good answers, ideas, thoughts. I'm glad Jeff posted this.

[Beer-lord]

The next best thing, Hansen/001 is having it's way right in front of me. More than enough for Tuesday's brew and 1 or 2 future beers. It's already started to crash. By mid day tomorrow, I'll likely be ready to cold crash.
Wished I could have tried the 090 but twas not to be.