How long can I keep ampoules of yeast from the NCYC before they begin to lose viability?
This depends on the conditions that the ampoules are kept in; at normal room temperature (21°C) the freeze dried yeast in the ampoules should remain viable for at least 6 weeks. We would recommend keeping the ampoule away from bright sunlight as this can affect the contents. The preferred method of storage for the ampoules is at 1°C in the dark. Under these conditions the freeze dried yeast in the ampoules should remain viable for many years. The NCYC has strains that have been stored by this method for up to thirty years and we have seen no sign of a drop in viability.
