View source for Freeze glycerol stocks of E. coli

To preserve all stocks of each strain derived from a unique colony, we will freeze glycerol stock at -80 C. 

# Put 37.5 µL of warmed glycerol in a pre-labeled sterile 1.5 mL tube. 
# Remove 212.5 µL of your overnight culture and add it to the appropriately labeled tube with glycerol. 
# Close the lid tightly and mix by vortexing. 
# When all 4 tubes are well mixed, give them to your instructor to put in the freezer.