FBS Aliquots Put a 500 mL bottle of Hyclone FBS into the tissue culture refridgerator to thaw. This will take at least 1-2 days. Once the bottle is thawed out, it must be heat inactivated at 55ºC for one hour. (Use the incubator in the lab, not in tissue culture.) After that, make ten 40 mL aliquots and ten 10 mL aliquots and store in the tissue culture freezer. Make sure you label the aliquots “Hyclone FBS”