Odd floc behavior in old 3068 slants

I had some old, original refrigerated slants of Wyeast 3068 from a year ago that I recently used in two weizen batches. Yes, I know one is supposed to reculture at 4-6mos but I made 10 of these at the time.

Both slants were viable when started on a stirplate in 10cc of sterile wort. I also streaked some on a plate and it grew as expected (though I did this as an experiment and did not pitch from it).

In both cases, the yeast from these 12mo old slants has radically looser floc. Instead of a yeast cake at the bottom of the primary there is more of a yeast zone with no definite margins. In the bottle, it is impossible not to kick up significant loose haze even in the first seconds of the pour. I would say that 95% of the yeast in the bottle makes it into the glass and it doesn't matter how it's poured.

Flavor profile is unaffected (other than that contributed by the physically suspended yeast), and, given that my young adulthood was informed by Schwaebian hefeweizen, I do not mind cloudiness. But this is really over the top.

I do not know how my replated 3a suspensions will behave. I will try them next. If they are normal I will replate/resuspend them. If they are not normal I will buy a fresh 3068 and reculture.

The yeast are likely "old", mutated, and generally not healthy. This causes a "dusty" yeast in the beer... it stays in suspension longer and doesn't flocculate or settle well. It's generally recommended not to reculture yeast that show these characteristics.

This happens pretty much every time I use 3068. Not having seen your primary myself, I don't automatically think something's unusual.

Never used this strain before but Wyeast says:

Classic German wheat beer yeast, used by more German brewers than any other strain. Dominated by banana ester production, phenols and clove-like characteristics. Extremely attenuative yeast, which produces a tart, refreshing finish. Yeast remains in suspension readily with proteinacous wheat malt. Sometimes used in conjunction with lager yeast and kraeusened to finish the beer and improve the overall dryness. High CO2 levels, typically at 2.7 - 3.2 volumes is desirable for best presentation. This strain is a true top cropping yeast requiring full fermenter headspace of 33%. Increasing pitch rates will reduce ester production. Alcohol tolerance: approximately 10% ABV

Origin:
Flocculation: low
Attenuation: 73-77%
Temperature Range: 64-75° F (18-24° C)
Alcohol Tolerance: approximately 10% ABV

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Are you saying it's got even less flocculation then before? Dusty?

Seems to me you're saying that the yeast does floc but then kicks back up? That doesn't seem too far off from the Wyeast descirption and if the flavor profile is still good I would hazzard a guess that it has not gone bad.

At what point in the process was the yeast originally cultured? What I mean is my general understating is that if you grab the yeast that has settled in a wash you'll get a lot of the highly flocculant yeast that will settle out early and under attenuate and if you gab just the suspended yeast you end up with an very low flocculant yeast that never seems to fall out of suspension and over attenuate as compared to the manufacture's specs.

I'm sure you know this, but German Hef's are often servered with yeast in suspention. Perhaps in your culturing techniques you've enhanced that particular charasteristics.

Can you give us more info on your original culture and how it flocculation characteristcs compare to this culture and the attunation rates of each?

ScottD13 said:

Are you saying it's got even less flocculation then before? Dusty?

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Yes. It was normal-for-weizen floc before in the first (several batches). Now, I would say that "dusty" is a perfect description.

ScottD13 said:

Seems to me you're saying that the yeast does floc but then kicks back up? That doesn't seem too far off from the Wyeast descirption and if the flavor profile is still good I would hazzard a guess that it has not gone bad.

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It stil flocs in the "generally in the bottom few inches of the carboy" sense but there is no definite margin like I had before where I'd get an inch or two of distinct yeast cake.

ScottD13 said:

At what point in the process was the yeast originally cultured?

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The slants were innoculated directly from the smack pack.

ScottD13 said:

I'm sure you know this, but German Hef's are often servered with yeast in suspention. Perhaps in your culturing techniques you've enhanced that particular charasteristics.

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Right, though I suspect that it is more likely that I let those slants go too far without reculturing, and they are acting out.

ScottD13 said:

Can you give us more info on your original culture and how it flocculation characteristcs compare to this culture and the attunation rates of each?

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Attenuation is still normal. No off-flavors.

All slants were used 1x; I made 10 slants originally so I didn't need to "double dip".

pitch from original culture: normal
pitch from culture from 20-day slant: normal
pitch from culture from 105-day slant: normal
pitch from culture from 210-day slant: normal
pitch from culture from 300-day slant: dusty floc
pitch from culture from 365-day slant: dusty floc

Yes, I know that yeast is supposed to be recultured after a few months.

I did reculture and suspend from one of those slants at the 240 day mark. I will plate some of that out and see what it does in my next batch.

Interesting...I'm at a loss. Guess it's just old yeast acting up...

Ok, I made a couple of plates from a suspended 3068 culture. If it's viable I'll step it up and brew with it. If it's normal floc that's my new culture.

If not, I have to spend another $7 for another smackie. Not a big deal, but this is certainly teaching me to stay on top of my reculturing (or switch to suspensions, based on the outcome here).

menschmaschine said:

The yeast are likely "old", mutated, and generally not healthy. This causes a "dusty" yeast in the beer... it stays in suspension longer and doesn't flocculate or settle well. It's generally recommended not to reculture yeast that show these characteristics.

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I think you are right.

I am not reculturing that line; I have a fork of the line from when it was performing normally. The forked culture has been stored in sterile, distilled water. We'll see if it's in any better shape. Thanks for your input.