After having frozen these three batches to below 0C it was time to defrost them so as to add the yeast. It took all day and night to have the temperature rise into the high teens early twenties. This morning The yeasts were rehydrated in grape juice taken from each batch that had been warmed to 38 C. Then after allowing the fermenting yeasts to cool to within 10 C of the main batches these starter batches were added back.
Two new yeasts are being tried both from Vintners Harvest an American company. The yeasts were sourced from a local home brew shop.
The Shiraz has VR21 which will go up to 15% alcohol the Shiraz has a high Brix reading of 24 and will need this.
“ Exceptional strain for full fruit red varietal wines with good structure, balance and colour. Excellent strain for red country wines.” Says the manufacturer.
The Merlot and Tempranillo have R56.
“Perfect for rich full bodied red wines with exceptional full flavoured complexity”
The Chardonnay was racked after the intial fermentation slowed. Now it rests in airlocked demijohns, occasionally giving off a little CO2 as the last bits of sugar are consumed by the yeast cells. Some of the demijohns wee racked to remove the gross lees and now it was time to try some further experiments. Some of the batches that had good skin contact now had few American Oak chips added. Just to see if there would be any flavour improvement. And yes an un-oaked demijohn was kept of each as a comparison.
These batches are in demijohns under refrigeration to keep the fermentation temperature between 12 and 15 C. They are bubbling away slowly. The airlocks aren't bubbling because they don't have water in them. Instead there is a little wad of cotton wool. This was recommended in one technical reference to enable H2SO2 to more readily escape. And it is escaping. There is a distinct rotten egg smell when the doors of the refrigeration units are opened.
These draining's from the Shiraz, Merlot and Tempranillo batches are all fermenting under airlock also under refrigeration. Once they are nearly finished they will be racked and a little addition of oak chips made just to add another dimension.
Has pretty much finished its fermentation but some skins are still apparent on the surface. The goal is to have these skins in contact with the wine for a minimum of 22 days before pressing and storing in demijohns with Oak chips to settle and age. There is a plastic sheet covering the container to keep out bugs and every day a little CO2 is squirted over the surface to add some further protection against infection. This is the nervous part of the process. While it was madly fermenting the CO2 gas produced as a by-product protected the wine but now the only protection is the small amount of Potassium metabisulphite that was added at the crush and the daily burst of CO2.
The fermentation has slowed but not finished. The skins rise but not much and a once or twice daily plunging occurs. This is also now under plastic protection and also getting a whisp of CO2.