CONTRIBUTION TO WINE

AWRI 796 produces low levels of aroma and flavour compounds and is considered to be reasonably neutral. It is a highly desirable yeast strain for the fermentation of distinctly varietal wines where the oenologist desires little or no interference from the yeast strain over the natural varietal character of the grapes. In red grape juices, AWRI 796 produces blackberry, plum and raisin aromas.

RATE OF FERMENTATION

A moderate to rapid rate fermenter at warmer temperatures 20–30˚C (68–85˚F) with a relatively short lag phase. For high maturity white grape juice of low solids, AWRI 796 may require careful management and temperature acclimatisation to ferment at lower temperatures (below 15–18˚C; 59–64˚F) and to successfully ferment to a high potential alcohol. Under these conditions it is advisable to allow the temperature towards the end of fermentations to rise above 15˚C (59˚F).

NITROGEN REQUIREMENT

AWRI 796 is technically a low nitrogen consumer and normally completes fermentation of low YAN musts of moderate maturity (<13˚Bé) without nitrogen addition. Whites: For high potential alcohol, low solids fermentations, several additions of nitrogen (100mg DAP/L) will help produce a high population of healthy yeast. Reds: AWRI 796 is more tolerant of low nitrogen, high potential alcohol red musts but will benefit from nitrogen addition. The AWRI believes that tolerance to low nitrogen in high solids red ferments is a result of lipids and amino acids which are released from the skins/solids during fermentation.

APPLICATIONS

AWRI 796 is generally recommended for red wine production, particularly varietal wines such as Shiraz/Syrah, Cabernet, Merlot and Pinot Noir. For successful white wine fermentations, such as Chardonnay, Sauvignon Blanc, Semillon and Riesling, it is advisable to carefully acclimatise the yeast to low temperatures prior to and during fermentation, and supplement the ferment with additions of nitrogen as required. Agitation and/or increasing the temperatures during the final stages of fermentation will assist to maintain the yeast in suspension.