After the primary fermentation has slowed down (after about 7 days) it’s time to check the specific gravity. What this tells us is how the density of the wine compares to that of water.
Grape juice is more dense than water. Thus before we fermented the grape juice the specific gravity was over 1.0. As the yeast converted the sugar into alcohol and carbon dioxide during fermentation, the density of the wine has been decreasing. A specific gravity less than 0.990 tells us that the primary fermentation has slowed down enough that we need to rack. Continue reading “Checking the Specific Gravity and Racking”