Frequently Asked Questions (FAQ)

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.

How long can I store live yeast from the NCYC?

Live yeast strains from the NCYC or strains grown from opened ampoules can be stored either in YM broth or on YM agar and will usually remain viable for up to 6 months from initial inoculation if kept at 1-8°C, although the exact time will vary according to the individual strain involved. The live strains can be kept over longer periods by subculturing although care must be taken not to introduce contaminants. We would recommend purchase of a new culture from the NCYC after 6 months to ensure quality and viability are maintained.

How do I choose a yeast strain for brewing a particular type of beer or lager?

Unfortunately most of the brewing yeast we have, have been received on a confidential basis and the depositors or customers who use the strains do not usually give us much feedback on how the yeast work as regards giving the final product its characteristics. We are therefore unable to give customers details on exactly which strains in the NCYC have been used to brew particular beers.

It is however usually possible to get a yeast from the collection which matches the charateristics of an older strain using the 'Tall Tube Codings' which are given with most of the strains. Our customers usually use these to select a yeast which they think is suitable for their purposes. It is difficult to predict exactly how a yeast will behave and what the character of the final brew will be, since this tends to vary depending on the other ingredients used and the exact brewing process. We usually suggest that a customer picks one or two yeast which look suitable and try trial brews. The full explanation of the 'Tall Tube Codings' can be found in the brewing yeast section of the web site.

Does the NCYC sell to home brewers and bakers?

We can supply to home brewers and bakers. However, since we specialise in very high quality starter cultures which are designed to be grown in the lab and bulked up for large scale brewing or baking, our prices tend to be prohibitive for the home brewer.

What is a Premium yeast strain?

Premium yeast strains are strains of greater commercial value, such as strains with specific applications and type strains.

Which yeast strains do you recommend for the production of bioethanol?

We have a range of strains that we recommend for this purpose, which include NCYC 614 Pachysolen tannophilus, NCYC 1403 Candida succiphila, NCYC 2545 Candida tenuis and NCYC 1541 Pichia stipitis. Further details and associated references about the strains can be found on the website if you type the NCYC number into the culture search. We also have a useful Special Application Search on the culture search page, where you can find strains that for example utilise xylose.