Could I re-hydrate and store an opened pack of S-04 yeast?

[Kunal Vanjare]

So I have come back to homebrewing after a lengthy gap of around a year and found that my fridge still has an opened pack of S-04 (the pack would have been sanitized & sealed with a clip). Now I don't remember how much of that yeast is still remaining or how viable it still is.

Do you'll recommend re-hydrating this yeast and storing the slurry in a sanitized box? That way I will even find out how much yeast there is in the packet.

I only make 1 Gallon batches.

 

[Miraculix]

No, throw it away and buy a new one. It is not worth the risk.

 

[RM-MN]

Pitch it into your fresh wort. It probably will be an overpitch in a one gallon batch but that won't matter much. If it fails or is contaminated, you have only risked one gallon. It most likely is just fine. I often have half a packet in the spring when I quit brewing and use it in the fall when I start up again. I've never had a failure or contamination issue.

 

[BrewnWKopperKat]

Currently, in the USA, an unopened package of S-04 weights 12.8 grams and contains 11.5 grams of yeast.

You could buy a fresh package of yeast as a backup (and to confirm the weight of the packaging), and initially pitch from the existing package of yeast. If fermentation fails to start, use the backup package for a repitch.

 

[odie]

is this a single pack or a 500g brick?

Either way, if it was closed tightly and in the fridge...go for it. Since it's not a full packet it will be an under pitch but it will probably start up and finish just fine.

But have another packet of S-04 ready if nothing happens within 24-48 hours.

But don't rehydrate. Just dry pitch. That's what the instruction say and I'd say that Fermentis knows more about their yeast than we will ever know.

 

[passedpawn]

So I have come back to homebrewing after a lengthy gap of around a year and found that my fridge still has an opened pack of S-04 (the pack would have been sanitized & sealed with a clip). Now I don't remember how much of that yeast is still remaining or how viable it still is.

Do you'll recommend re-hydrating this yeast and storing the slurry in a sanitized box? That way I will even find out how much yeast there is in the packet.

I only make 1 Gallon batches.

I would not re-use dry yeast that has been opened previously.

There was a major problem with Nottingham yeast many years ago. It was not fermenting correctly, and resulted in off-flavors. The cause was small holes created in the dry yeast package when their date stamping machine stamped them. These little holes and the resulting oxidation / desiccation of the yeast was disastrous. I was affected by this problem and abandoned Nottingham at that time.

I hope I remember this correctly. If not, my apologies - perhaps someone can correct me if so.

 

[hotbeer]

How important is that gallon of beer too you? Experiments can be more useful than dogma.

You can pitch it and see what it does and maybe it'll be no discernable difference than if you got a new pack. But maybe your next thread here will be titled "beer is doing nothing in the fermenter... re-pitch or toss?"

I might toss the yeast in the bin or pitch the yeast in the fermenter. Depends on my mood in the moment and how soon I could get more.

You decide. Let us know if you use it and it's good beer or not.

 

[davidabcd]

As mentioned, it's not worth it. Maybe as an experiment but nothing else.

 

[TestTickle]

When you say it was sealed with a clip, is the packet just sitting like that in the fridge, or did you store the packet in something else like a ziplock bag? I frequently do smaller batches and use partial packets of yeast. I store them similarly, but I also put the sealed packet into a ziplock bag to help make sure it doesn't get exposed to more air. I've kept them stored for months like that with no issues.

With that said, yeast is cheap, I'd just buy another packet.

 

[Dgallo]

Us-04 is $6 dollars or less, why even risk it.. yeast health is the number 1 thing that makes quality beer

 

[RM-MN]

Either way, if it was closed tightly and in the fridge...go for it. Since it's not a full packet it will be an under pitch but it will probably start up and finish just fine.

I'm not sure that you or others read the part of the batch size being one gallon. If it is 1/4 pack it is still an overpitch unless much of it is dead. This isn't like a 10 gallon batch where the cost of the ingredients would suggest a new pack.

 

[odie]

totally overlooked 1 gal. we are all programed to automatically think in 5 gal terms. 1/4 packet is by no means an over pitch on 1 gal. the fact that the packet was already opened makes one assume the packet was already partially used on another batch in the past.

assuming it's a good 1/2 pack I think the OP is good here on the pitch.

 

[Brewdog80]

Why ask? 1 gallon? go for it. If decently close to expiration date, day 6 months, nonissue

 

[davidabcd]

lengthy gap of around a year and found that my fridge still has an opened pack of S-04

The cause was small holes created in the dry yeast package when their date stamping machine stamped them.

That is one forehead-smacking, bad error. Those make me wonder how functioning bridges get built.

 

[BrewnWKopperKat]

Lallemand has some information on how to work with partial packages of yeast.

On the storage tab on this page (link):

Dry yeast is packaged under vacuum in 500g packs or 11g sachets and must be stored dry, below 4˚C (39˚F). Exposure to humidity and oxygen will affect the viability and vitality of the yeast. [...] Once a pack or sachet is open, use immediately for best results. If kept sealed (or re-sealed) under vacuum and stored under appropriate conditions, dry yeast can be used until the indicated expiration date, which is typically 2-3 years after manufacture.