We have recently been advised by our supplier that Wyeast have begun to phase out the "Propogator" packs (Smack Packs) of their liquid yeasts and replace them with the larger "Activator" packs. These contain around 3 times as many active yeast cells as the propogator packs and the contents can either be activated by smacking and then left for 3-4 hours to begin to swell, or can be pitched directly into the wort. The Activator packs contain a minimum of 100 BILLION yeast cells in yeast slurry which is more than enough to inoculate 5 gallons of standard strength (1034-1060 SG) ale wort.