🍷 Glucose

Glucose is one of the two main sugars of grapes. The other is fructose. Together they make up almost all the sugar in a ripe berry. Glucose is not as sweet as fructose, but there is a lot of it in grape juice.

It matters especially for wine. Yeast eats glucose and turns it into alcohol and carbon dioxide. This is fermentation. The more sugar in the grapes, the more alcohol can result if the yeast finishes the job. If fermentation stops earlier, sweetness is left in the wine.

Usually yeast prefers glucose first, and fructose is left toward the end. That is why sweet wines more often keep fructose.

Glucose is found in other foods too. For example, the milk sugar lactose consists of two parts: glucose and galactose. So wine and milk are linked through the same sugar.