Bulk dry yeast

[golfandbrew]

I was shopping on the interwebs and found a homebrew supply shop is selling 500 gram packs of US-05.

Does anyone use these over multiple brews?
Surely there is a contamination risk between brews, how risky is this?
Would opening and closing the pack repeatedly have any effect on the yeast viability over time?
Would the yeast lose viability over time just from the packet being opened and stored back in the refrigerator?
Any other concerns I am over looking?

Thanks and cheers

 

[budonze]

I don't think these packages are meant to be opened and decanted from. According to Fermentis, once the package is opened, it should be used within 7 days.

This package appears to be geared towards micro brewery size batches.

 

[McGarnigle]

From Fermentis:

"Opened sachets must be flushed sealed and stored at 4°C (39°F) and used within 7 days of opening."

http://www.fermentis.com/wp-content/uploads/2016/12/SafAle-US-053.pdf

EDIT: what budonze said.