Imperial L17 Harvest, EXPIRED

What do the dates mean?
Best Before (BB) according to the manufacturer

This great lager strain combines good flocculation characteristics with low sulfur and low diacetyl. Clean fermentations produce amazing bock, Helles, pilsner, dunkles, and just about any other lager style you throw its way. Fantastic choice for a house lager strain. 

TEMP: 50–60F (10–16C)
FLOCCULATION: MEDIUM
ATTENUATION: 70–74% 
ALCOHOL TOLERANCE: 10%