Dry Yeast - how long to store?

[BKBrews]

Really quick question and I'm hoping someone can answer me quickly (30min into a mash in). I'm using US-05 yeast and just noticed that the packet says to use in a short period of time once open.

I've got an open packet I was going to use but it's been sitting in my fridge for about 2 - 3 months. I have another fresh packet too. Should I turf the older one? It's been in a zip lock bag with all of the air squeezed out.

 

[warra48]

I'd use it. Sounds like it's been stored well enough. Been stored better than the crappy little yeasts sitting on top of cans in some HB shop or suckermarket at ambient temperatures.

 

[BKBrews]

Thanks mate - I think I will. It's not actually the packet that says to use shortly - I think I saw it on the fermentis site, but could have just been on a forum or something. Not sure, I've done so much research in the last couple of months.

 

[SBOB]

why would you have a partially opened packet (curious)

 

[BKBrews]

I've only been doing small batches mate (5L). Software I've been using has only called for 3 - 4g per recipe, so 1 packet has got me 3 brews.

 

[peteru]

Once you open the packet you expose the yeast to oxygen (and moisture through condensation) and as a result the degradation process speeds up significantly.

Here's a tip: Open the new packet and compare the appearance and smell of the yeast to the old packet. If you can tell the difference you know that the old yeast is less than optimal.

 

[TwoCrows]

You can use it as a nutrient in the boil , I use yeast from kits for this purpose.

 

[Bribie G]

For future ref, dried yeast stores great in the freezer. I've come across forgotten packets after 3 years and they fire up just fine.

Apparently one of the Apollo missions landed near an old NASA "lander" probe and took samples, and they found microorganisms that had been put there when someone sneezed while assembling the old lander and had survived for years frozen to near absolute then roasted by the sun over the lunar "day". They were still viable.

Thread now open for panspermia comments. h34r:

 

[razz]

I've got the remnants of a 500g brick in the fridge which I bought over two years ago and it still fires no props.

 

[phonos]

I have >5 year old lalvin 71b stored in a zip lock bag in a fridge that manages to ferment mead up to ~16%abv, so I reckon you should be ok