Labo VinSparkling wine
Sparkling wine is a wine refermented in bottle. This second fermentation is obtained by adding, at the bottling, yeast, sugar and yeast nutrients. The fermentation will not stop when all the sugar is consumed, but when the internal pressure created by the produced CO2 reaches 5-6 bars. At this pressure, yeasts are inhibited, do not ferment any longer and settle.
In order to be able to referment for sure in bottle, a wine must possess some peculiarities that, for a still wine, are flaws:
- low alcohol rate (maximum 10-11 % vol);
- very low SO2 rate (do not add metaK at the racking time);
- fullness in yeast nutrients;
- presence of yeasts;
- presence of sugar.
Method
The wine has to be perfectly clear. Add to the wine that will become sparkling (for 10 L):
- 4 g nutritive salts;
- sugar (200 g for a brut, 250 g for a dry, 350 g for a half-dry, 450-500 g for a sweet).
If necessary, measure the acidity and adjust it to 8 g/L (7 g/L for honey or flowers wine) by means of citric acid (0.85 g citric acid equals 1 g tartaric acid).
After complete dissolution, bottle the wine in champagne bottles, specially studied to resist high pressures.
Add in each bottle, by means of a pipette, 2 mL of a well activated champagne yeast culture, shaking the culture before each sampling to avoid yeast settling.
Place a champagne cork or plastic stopper and a wire hood.
Store the bottles in a cold place (10-12° C). The wine becomes cloudy, which indicates that the fermentation occurs. When yeasts settle, the wine becomes clear and the fermentation is finished.
At this time, you can both use the traditional (champenoise) method [ Called today "traditional method". This is a method of yeast extraction after fermentation in bottle (at least 3 month). At the end of fermentation, the bottles are inclined, neck downward, put on a device called "pupitre". They are regularly revolved (once a day) so as to let slip the yeast into the hollow plastic stopper. When the whole yeast is in the stopper, the bottles are cooled (0-4° C) and their neck is plunged in a mixture of ice and salt. The wine in the stopper freezes. The stopper is removed, taking the frozen wine and the yeast. This removed wine is replaced by wine eau-de-vie, and the final cork is placed. Nowadays, more and more immobilized yeast in alginate beads are used. They are much more easily removed. ] , or put the bottles right and store them at very low temperature (up to -5° C). When the sediment is well packed down in the bottom, delicately remove the cork, rack in another bottle avoiding the lee, complete with wine from another bottle; place cork and wire hood.
A mild yeast deposit is admissible if champagne yeasts were used. These break down slowly and settle as grains larger than other yeasts.
Diluted fruit wines, honey, flowers, leaves wines produce very good sparkling wines whose fruity and refreshing character given by a good acidity (7-8 g/L), is well appreciated.