Are the yeast pure cultures?
Yes. All Fermentis yeasts are single strains, pure yeast grown from a single yeast cell in our laboratories.
Are the strains genetically modified?
No, all are naturally occurring yeast held in our yeast bank.
Will dry yeast affect the fermentation performance and the flavours of the beer?
Dry yeast performs equally well as fresh yeast with regard to fermentation rate, limit attenuation and yeast sedimentation. When using the same yeast strain, dry yeast will produce identical beer analytical profiles and beer flavour profiles to fresh yeast.
How does the cost of dry yeast compare to conventional yeast propagation?
The cost of propagation is often unknown to the brewer. The capital expenditure in a propagation plant only accounts for c. 20% of the overall cost of yeast propagation with the remaining 80% corresponding to utilities, labour & supervision, maintenance, QC and production materials (wort) costs. In most cases dry yeast compares favourably to propagated yeast and brings additional advantages (flexibility, pre-QC cleared product, etc.).
Can the yeast be re-pitched and how many times?
Depending on the integrity of the yeast handling system and the stress placed on the yeast by the brewing process it is possible to re-pitch. The exact number of cycles is dependant on the brewery environment. Dry yeast has proven very effective over 5-6 brewing cycles.
Do dry yeast contain traces of hops compounds?
No. Fermentis yeast are manufactured on hops free media. Beers produced with Fermentis yeast are suitable for hopping with hop extracts to prevent light-struck flavour issues on storage. There is no cross contamination due to the yeast.
Are dry yeast suitable for high gravity fermentations?
Fermentis dry yeast are propagated in fed batch systems where nutrients and Oxygen are continuously brought to the fermentation media thus enhancing the fermentability of the yeast. Fermentis dry lager yeast and in particular Saflager S-23 have shown increased performance over fresh yeast for high gravity brewing, successfully fermenting wort with original gravity of up to 22 Plato.
Does the wort need Oxygenation / aeration?
As the yeast is grown aerobically, the yeast is less sensitive on first pitch. Aeration is recommended to ensure full mixing of the wort and yeast.
How long does the yeast last in storage?
The sachets are stable for two years from date of manufacture with no significant loss of viability and fermentation activity. Fermentis dry yeast should be stored below 10C to ensure optimum fermentation performance.
Can I use soft sachets?
No. If the sachet is soft to the touch, the seal has been damaged allowing Oxygen to enter the package. As the yeast enzymes will be activated, the glycogen reserves will be depleted causing a loss of viability over time.