# Expired Dry Yeast



## losp (25/8/10)

Hi all,

i have some expired dry yeast that is a couple of months old. is it still use-able?
will they all die or perhaps produce off flavours?

if it makes any difference its beenin the fridge the whole time.

losp


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## rendo (25/8/10)

Hello Losp,

short answer = YES (because you have stored it in the fridge, good move)

However, yeast is cheap, what I would do is make a yeast starter....OR at least rehydrate the yeast (easy to find out how by searching here...sorry...its bed time otherwise I'd type it all out for you).....this will help make sure its viable.

What are you brewing? If you are doing a cheap brew eg kit & kilo then just use that yeast, but if you are doing an expensive brew then it goes without saying to spend a few extra dollars to ensure you get a top result.

rendo




losp said:


> Hi all,
> 
> i have some expired dry yeast that is a couple of months old. is it still use-able?
> will they all die or perhaps produce off flavours?
> ...


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## Synthetase (25/8/10)

Just make a starter culture and it'll probably be fine. That will tell you if there were viable cells in the first place and let them multiply up for wort fermentation.


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## Andrew Coleman (25/8/10)

Is it a bought yeast or from under the lid type yeast?
If its from under a lid of a kit can then keep it to use as yeast nutrient (by boiling and killing the yeast, i've saved up quite a couple from when i did kits, come in handy)

If its a bought yeast deffinetly try doing a starter mate, should be fine, just need a kickstart.

Also check use by dates when buying yeasts, keep yeast stored in the fridge, never let it get too hot or put in freezer as this will kill the yeast.

Drewey


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## Screwtop (25/8/10)

rendo said:


> what I would do is make a yeast starter....OR at least rehydrate the yeast






Synthetase said:


> Just make a starter culture and it'll probably be fine.






Drewcifer said:


> If its a bought yeast deffinetly try doing a starter mate, should be fine, just need a kickstart.



Keeping the yeast in the fridge after purchase is recommended. However you never know how it's been treated during transport/storage prior to your purchase, even if the HBS where it was purchased had it stored correctly. 

I would not make a starter, any small amount of viable cells will kick off and begin working, to the untrained eye this will appear normal and in it will go.

Rehydrate to proof the yeast according to manufacturers recommendations. If the yeast responds and is nice and frothy then pitch it.

Can not seen any point in making a starter using dried yeast, manufacturers ensure each sachet contains a hugh amount of cells, more than required for pitching to a 20 odd litre batch. 

From Lallemand:



> Yeast need a trace amount of oxygen in an anaerobic fermentation such as brewing to produce lipids in the cell wall. With out O2 the cell cannot metabolize the squalene to the next step which is a lipid. The lipids make the cell wall elastic and fluid. This allows the mother cell to produce babies, buds, in the early part of the fermentation and keeps the cell wall fluid as the alcohol level increases. With out lipids the cell wall becomes leathery and prevents bud from being formed at the beginning of the fermentation and slows down the sugar from transporting into the cell and prevents the alcohol from transporting out of the cell near the end of the fermentation. The alcohol level builds up inside the cell and becomes toxic then deadly.
> 
> Lallemand packs the maximum amount of lipids into the cell wall that is possible during the aerobic production of the yeast at the factory. When you inoculate this yeast into a starter or into the mash, the yeast can double about three time before it runs out of lipids and the growth will stop. There is about 5% lipids in the dry yeast.
> 
> ...






Drewcifer said:


> Also check use by dates when buying yeasts, keep yeast stored in the fridge, never let it get too hot or put in freezer as this will kill the yeast.



Incorrect!

From Lallemand



> Should I refrigerate or freeze my dry yeast until I use it?
> 
> Yes, although dry yeast can be stored at room temperature and performs well for the duration of the shelf life it is preferable to store it at colder temperatures. Dry yeast will always lose some of its viability and activity over time but at colder temperatures these losses are less than at warmer temperatures. If you choose to freeze your dry yeast for storage, let it warm to room temperature in the package before rehydration & pitching.



More facts available here than AHB : http://www.danstaryeast.com/

Screwy


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## flano (25/8/10)

I used some out by about 4 months.

beer is crap.

won't do it again.


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## Nick JD (25/8/10)

beernorks said:


> I used some out by about 4 months.
> 
> beer is crap.
> 
> won't do it again.



I've used some out by 2 years.

Beer is great.

Will do it again.


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## flano (25/8/10)

Nick JD said:


> I've used some out by 2 years.
> 
> Beer is great.
> 
> Will do it again.




ok ...

won't make that beer again then.

cheers.

you a surfer nick?

My inlaws are from Kingscliffe ..go up every xmas.
I always seem to get lucky with great waves....been on a 5 year roll now.


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## losp (25/8/10)

Its Saflager 34/70 ive got 2 packets of itI think i will play it safe and use it as nutriant, i bought them for like $2 each anyway.

Thanks guys.


Drewcifer said:


> Is it a bought yeast or from under the lid type yeast?
> If its from under a lid of a kit can then keep it to use as yeast nutrient (by boiling and killing the yeast, i've saved up quite a couple from when i did kits, come in handy)
> 
> If its a bought yeast deffinetly try doing a starter mate, should be fine, just need a kickstart.
> ...


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## Nick JD (25/8/10)

beernorks said:


> ok ...
> 
> won't make that beer again then.
> 
> ...



It's best to rehydrate, or make a starter from expired yeast to ensure it's healthy. Frozen dried yeast last ages past the expiry date. This year I used a 2007 dated pack of US05.

I surf a bit - 3 blocks from the beach it'd be crazy not to!


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## Lecterfan (25/8/10)

My feeble 2c worth: I rehydrated two saflager w 34/70 sachets last week, added a small amount of wort and got it into a frothy cream and pitched it and everything was fine. Both sachets had a use by date of July this year. Only out by a few weeks, they were still incredibly active. I only used them as I got them cheap BECAUSE they were out of date...first time I've used dried yeast in about 3 years haha.


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## Ross (25/8/10)

Dry yeast generally has a best before date of 2 years from manufacture; this is based on the yeast being stored below 20c
If stored in a fridge/freezer you can pretty well double the best before date.

Cheers Ross


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