A robust and versatile organic yeast for making complex, aromatic organic wines.

Ossia is Renaissance’s high performance certified organic (NOP/COR) yeast that prevents the formation of H2S. In organic winemaking, H2S and its associated reductive character faults can’t be minimized by the conventional methods of adding inorganic nitrogen or copper. Ossia is an exciting new tool for organic winemakers to proactively guard against reductive faults while also improving aroma profiles through increased expression of tropical fruit esters.


Viability / Living cells: > 1.0 x 1010 cells/gram
Package Sizes:
500g and 10kg vacuum packed foil sachets.
Storage Conditions:
Store cool and dry, 4 - 15⁰C (39 - 59⁰F). Do not freeze!
Inoculation Rate:
200 - 350g/1000L (2.2 - 3.3lbs/1000 gallons)

Note: inoculation range is based on the juice sugar content and condition of grapes.

  1. Prepare a chlorine-free, 3:1 water to juice mixture of approximately 5 times the yeast weight at 38 - 42°C (100 - 108°F).
  2. Gently sprinkle the yeast into the water-juice mixture and, without stirring, allow 10 minutes for hydration.
  3. Stir the yeast into the water-juice mixture allowing it an additional 10 minutes to fully hydrate.
  4. Add enough juice to the yeast suspension to lower the temperature by 5ºC (9ºF). Let mixture acclimate for 5 minutes.
  5. Repeat step 4 until the temperature of the yeast suspension is less than 8°C (15°F) warmer than the must or juice to be inoculated.
  6. Slowly add the yeast mixture into must or juice.

Note: Directly adding dry yeast to the must or juice tank is not advisable.

Ossia - 2015 Product Sheet Ossia - 2015 Product Sheet (324 KB - )


Ossia maintains the natural acidity of the juice while also producing increased amounts of esters, creating fruity and lively wines which linger on the palate. Ossia is a very versatile strain and is recommended for use in white, red, and fruit wines and cider. Ossia’s aroma profile and its ability to arrest fermentation by lowering the temperature also make it a good choice for sweeter styles of wine.

Recommended varietals include White Wine, Red Wine, Fruit Wine, and Cider.


When fermenting to dryness, it is recommended to increase temperature to > 20 °C near the end to ensure a proper finish. Nitrogen supplementation is recommended during the initial 1/3 of fermentation, especially when fermenting at warmer temperatures or in highly clarified musts.

*Grams of sugar required to produce 1% alcohol (v/v). Varies depending on the sugar and nutrient composition of the must and environmental conditions.

Quality Guarantee

Renaissance Yeast guarantees the quality of its products sold in their original packaging, provided they are used in conformity with the expiration date and the storage conditions noted above.

The information is true and accurate to the best of our knowledge. However, this data sheet is not to be considered as a guarantee expressed or implied, or as a condition of sale of this product.


Ossia (2018) Ossia (2018) (503 KB - )



Optimal Temperature

18 – 32°C

Cold Tolerance


Alcohol Tolerance



0.20 - 0.35 g/L

Conversion Factor

16.5 g/L


6 - 8 g/L

Volatile Acidity


Nitrogen Requirements


Killer Factor



mod - high

Foam Production


SO2 Production

none - very low

H2S Production