Old dry yeast packets, any chance of problem other than low viability?

[Dland]

Just wondering if anything other than yeast could get going in an old dry yeast packet. I just racked a batch that seems just a little off, and one variable is I pitched a couple packs of 2017 yeast in addition to some 2020 packs. Yeast packs stored in sealed container, fairly stable cool temp.

Fermentis S-189, first pitching(not recycled or yeast cake). Fermentation got going right away and ran normally, 54F. Beer just a little sour and more trub than usual for this yeast.

Probably if infected, it is something else, but just wondering about this variable.

 

[Hoppy2bmerry]

If it was a sealed old packet it should not be anything but yeast... and since you pitched other yeast as well it shouldn’t be off from under pitching, right?

 

[Dland]

One would presume package contains nothing but yeast and whatever coating Fermentis uses. But perhaps that is assuming a more pure product than is the reality. Was not under pitched.

 

[Steveruch]

Properly stored dry yeast only loses about 4% vitality a year.

 

[RPh_Guy]

Just wondering if anything other than yeast could get going in an old dry yeast packet.

Nope. There's too little moisture for anything to grow, if that's what you're asking.

 

[Northern_Brewer]

Although....

There's rumours that Fermentis had some contamination issues back around that kind of time, so it may not be the age that's the issue but just the specific batch.

 

[Dland]

That is interesting indeed. While I never rule out the possibility I missed something, my sanitation regime is fairly rigorous these days.

 

[Dland]

So above mentioned beer tastes like it might turn out drinkable, not sure, but defiantly some sour going on.

This was a lager, so normally it would spend 2-3 weeks secondary with spund, D rest ect.

Thinking of cold crash sooner than normal. Anyone know if cold will slow souring (bacteria I presume ? ) to favor more beer tasting beer ? Of course I'll dump if I don't enjoy, maybe it will be OK, maybe I'll learn something.

 

[RPh_Guy]

Anyone know if cold will slow souring (bacteria I presume ?

Yes, it will. (And yes, generally bacteria are responsible for souring).

contamination issues back around that kind of time

Contamination with lactic acid bacteria?

 

[IslandLizard]

Yeast packs stored in sealed container, fairly stable cool temp.

They should be at least kept refrigerated, or better yet, frozen. Their viability may have been much lower due to higher storage temps.
How long did it take before fermentation started? You may have had some infection taking hold before the yeast got up to speed. Hence some sourness.

I've used frozen sachets of US-05 that were 2-3 years past exp. date. One sachet per 5 gallons, rehydrated, then pitched in well aerated wort. They took off within 24 hours. No sourness, or other off flavors from what I could tell at the time.

 

[Dland]

They should be at least kept refrigerated, or better yet, frozen. Their viability may have been much lower due to higher storage temps.
How long did it take before fermentation started? You may have had some infection taking hold before the yeast got up to speed. Hence some sourness.

I've used frozen sachets of US-05 that were 2-3 years past exp. date. One sachet per 5 gallons, rehydrated, then pitched in well aerated wort. They took off within 24 hours. No sourness, or other off flavors from what I could tell at the time.

I use Fermentis dry yeasts most of the time and in all cases but above, well before expiration date. Dry pitched, they are always working by next morning. Above batch got 2 current packs of S-189 yeast, and two older packs I found. I figured they would either be of low viability, or I'd be over pitching, like many here recommend with lagers. Either way, it should not have made much differnece, except perhaps I'd experience the "glory" of over pitching expensive yeast, as so many lager brewers on this forum espouse. That turned out to be a mistake it seems, if the old ones were contaminated.

I brewed the same 10 gallon batch a week later and just added two current dated packs, and it was also working the next morning, but a little slower, as I would expect from a cool fermented lager. The batch in question did work more vigorously, not weirdly so, but more at the pace of an ale yeast in mid 60'sF. It was ready to rack in a week, where normally my cool lagers take around 12-14 days in primary to reach gravity where I rack and spund.

 

[Dland]

Reporting back good news of this batch, I tasted some last night and it tastes pretty good. Not sure if sour, but something different than usual S-189.

It has only been lagering for a couple of weeks, so it has more time to clear before it is at its prime. I also skipped most of the D rest and temp ramps, which might make it taste a little different.

When I tasted crashed sample after final trub dump(normal procedure for me), it tasted sort of OK, but heading sour. I'm thinking the speedy crash must have helped, and whatever "it" is does not grow at 31F.

 

[kh54s10]

Reporting back good news of this batch, I tasted some last night and it tastes pretty good. Not sure if sour, but something different than usual S-189.

It has only been lagering for a couple of weeks, so it has more time to clear before it is at its prime. I also skipped most of the D rest and temp ramps, which might make it taste a little different.

When I tasted crashed sample after final trub dump(normal procedure for me), it tasted sort of OK, but heading sour. I'm thinking the speedy crash must have helped, and whatever "it" is does not grow at 31F.

Since you did things differently I am not surprised that the beer tastes different.

 

[Dland]

Pretty sure I know what is from lack of D rest, as well as short lager time at this point. This is different, good but a little sour and somewhat more effervescent than just well carbonated. I'm sure I'll drink it, might not do again intentionally.

Guess I'll get a gravity reading off the next one, gonna drink this. ;}