The first step is rehydration, since the yeast is initially dehydrated. It’s a fifteen-minute step, where yeast come out of their ‘sleep’ in warm water. Then, rude awakening, you add a small amount of wine and some sugar. The day after, you have to add some sugar, and a lot of wine.
Finally for the next few days, you will mix and aerate the culture so the yeast population can grow and ultimately thrive once transferred into the wine and in the bottle. At this stage, oxygen is key for yeast to synthesise very important components of their membrane (sterols and some fatty acids), increasing their resistance to alcohol. In fact, twelve days of bottling means twelve cultures. Four days for each at two aerations a day, that is a total of thirty-two hours of work!
Taking those steps, the second fermentation will go smoothly and in a few weeks the yeast will have converted the base wine into a sparkling wine. Else, you could end up with a batch of wine not fermenting all the way: still sugary and not very fizzy. Yikes!
