Pre-expanded yeast pack

[sa_brew]

I purchased an out of date Wyeast pack that looks like it had already been smacked. I shook the packet, and it sounds like the yeast pack inside has not been popped yet. Is there any chance the yeast leaked out, or could this pack be infected?

[nighthawk]

It’s my understanding that the pack inside is wort. Not yeast.

Activator™ packages include a sterile liquid nutrient pouch that, when “smacked”, releases its contents into the yeast slurry and “activates” the package. The available nutrients initiate the culture’s metabolism which in turn generates CO2 and causes swelling of the package. This process will reduce lag times by preparing the yeast for a healthy fermentation prior to inoculation. Activation also serves as a viability test of the culture. Expansion of the package is an indicator of healthy (viable and vital) yeast. Although beneficial, cultures do not need to be activated prior to inoculation.

http://www.wyeastlab.com/hb_productdeta ... oductID=16

If it’s popped or not, I’m not sure how you tell by the sound of it.

Make starter and see how it smells/tastes. Of course it may smell/taste bad and still be good.

Unlikely it’s contaminated from the lab. I would brew with it.

[sa_brew]

I always do a starter. I just wanted to be prepared if I had to pour the yeast pack directly into the starter solution.

[baratone_brewer]

Sometimes a swollen pack can be caused by a small amount of sugar or CO2 being left in solution at the time of packaging. CO2 can be released from solution or the yeast can consume the sugar and create a small amount of CO2.

[harpdog]

Wyeast has a nice FAQ on their site http://www.wyeastlab.com/faqs.cfm#r15 .

It says the yeast is in the main solution, not the inner pack:

[i]1. Is the yeast in the small inner packet or in the foil pouch itself?

The yeast is in the main foil pouch. The small inner packet contains the sterile nutrient and wort that feeds the yeast before it is added to your fermenter. First, the package and the nutrient packet are sterilized (autoclaved) then the yeast is added and the package is sealed. [/i]

[nate42]

I’ve had this happen a few times before. Doesn’t seem to hurt anything. I always make a starter, so I knew the yeast was viable.