VIN 13

We have been busy cold settling our Chenin Blanc juice in a 50 degree temperature controlled settling chamber, in order to rid the juice of most of the large particulate matter, the gross lees and then racking it to a clean keg to warm up to fermentation temperature, 62 degrees F. This is a tricky procedure because the juice must be racked out of one chamber, the used keg is then removed from the chamber and then the juice is pushed by nitrogen into a fresh keg in a warmer fermentation chamber. Since we only have 3 temperature controlled chambers (freezers), we are now down to putting the racked juice into the same fermentation chamber to warm up.
For all of our previous fermentations, we have used the yeast called QA23, based on a South African study called Effect Of Yeast Strain And Lees Contact On Chenin Blanc Wine Quality, in the on line journal WineLand. This article focussed on the comparison between the following four yeast strains VIN 13, N 96, QA 23 and NT 116 based on:

• successful completion of fermentation
• ester production
• formation of lees character
• overall wine quality

The study found that:

• Yeast strains QA 23, N 96, VIN 13 and NT 116 produced the highest levels of acetate esters and corresponding fruitiness
• Yeast strain QA 23 produced the most fruitiness, lees character and highest overall wine quality
• Yeast strain N 96 produced wines with slightly more body than the other yeast strains
• All yeast strains exhibited low levels of sulphury flavours due to aeration of the lees directly after fermentation
• For those yeast strains that were on lees for five months, nuances of bread, sparkling wine, citrus and buttery flavours were observed

In 2015, the first year that we used QA23, we let the fermentation go completely to dryness, which we later learned was one of the characteristics of this yeast. For the majority of our fermentation, we are using QA23, but we thought it might be instructive to try another yeast, so we chose VIN 13. We are fermenting the juice with VIN 13 in one of our 15 gallon kegs. In rehydrating and tempering the yeast, we thought that the initial foam it produced was darker in color and much finer.

Right now, we are waiting for fermentation initiation.
Reference:
1. Johann Marais and Neil Jolly, Oenology research, Winetech TechnicalEffect Of Yeast Strain And Lees Contact On Chenin Blanc Wine Quality, Oenology research, Winetech Technical, 1 September 2005.
2. Sctt Lab, VIN 13 Technical Sheet.