active dry yeast
SafŒno UCLM S325 Fermentis Yeast

Available in 500g and 10kg packaging


Type of wine:

Fermentis White wine


Varietal characters at their best.

SafŒno™ UCLM S325 was selected by the Castilla La Mancha University for its ability to reinforce the structure of white wines while optimizing the expression of their character.

Still wines. Dosage: 20 g/hl
In case of musts with a high potential degree. Dosage: 20g/hl + 20g/hl of SafŒno™ BC S103 at mid fermentation (with a preliminary acclimatization)

For white wines with low structures

With its high glycerol production this strain brings structure to light and low aromatic varieties (Airen, Trebbiano, Chardonnay).

For aromatic cultivars

Its ß-glycosidase activity enables the release of terpenic type varietal aromas (Malvasia, Muscat, Alvarinho, Loureiro, Riesling, Viognier, Gewürztraminer, Pinot Gris) but SafŒno™ UCLM S325 also gives very good results on very aromatic cultivars such as Sauvignon Blanc or Sémillon.
Above 13% vol./vol., SafŒno™ UCLM S325 metabolism may be disturbed. It is thus very well adapted for the production of sweet wines. For wine making above that degree, adequate nutrition and/or associating SafŒno™ UCLM 325 with SafŒno™ BC S103 may be beneficial to keep the aromatic potential of the variety while achieving a correct fermentation.


  • Gently pour the desired quantity of yeast in 10 times its weight of tap water at 30-35°C in a wide vessel. Pay attention to cover all the water surface area by creating a thin layer of yeast.
  • Leave to rest for 20 minutes.
  • Gently stir to complete yeast rehydration while avoiding the formation of lumps prior acclimatization.
  • Double progressively the volume of the yeast suspension by adding must from the tank while stirring the mix
    so that the temperature of the yeast starter decreases and yeast activation starts.
  • Leave to rest for 10 minutes.
  • Homogenize and incorporate the yeast starter in the fermentation tank during a pumping over with aeration


Carton of 20 vacuum-packed sachets of 500g each (Full box net weight: 10 kg).
Carton of 1 vacuum-packed box of 10 Kg (Full box net weight: 10 kg).


The high rate of dry matter of our yeasts assures an optimum storage in its original packaging at a temperature not higher than 20°C (during 3 years) and 10°C for an extended storage (4 years). Fermentis guarantees the product complies with the International Oenological Codex until its Best Before End Date in the storage conditions mentioned above.


Each Fermentis yeast is developed under a specific production scheme and benefits from the know-how of the Lesaffre group, world leader in yeast manufacturing. This guarantees the highest microbiological purity and maximum fermentation activity.

Fermentation abilities:

→ Rapid fermentation start
Good fermentation strength on clarified musts
Alcohol tolerance: Not recommended above 13% vol./vol. without adequate nutrition
Strong nitrogen requirement: In a must whose available nitrogen is between 150 & 180 mg/L, this strain requires at least 2 nitrogen supplies (20 g/hl DAP + 20 g/hl Springferm™ at yeast inoculation and 20g/hl DAP or Springferm™ between third and mid fermentation)
Fermentation temperature: 12 to 35°C

Metabolic Characteristics:

→ Sugar/Alcohol yield: 16.5 g/L for 1% vol./vol.
Low production of volatile acidity, SO2 and acetaldehyde (less than 24 mg/L)
High glycerol production: 10 g/L
ß-glycosidase activity increasing the aromatic potential of terpenic varieties

Ingredients:yeast (Saccharomyces cerevisiae*), Emulsifier E491 (sorbitan monostearate)

The data contained in this technical sheet are the exact transcription of our knowledge of the product at the mentioned date. They are the exclusive property of Fermentis-Division of S.I.Lesaffre. It is of the user responsibility to make sure that the usage of this particular product complies with the legislation.