Sugar is a critical element in wine production. During the alcoholic fermentation process, yeast consumes the natural sugars in the grape juice, or must, converting them into ethyl alcohol and carbon dioxide. For certain wine styles, such as semi-sweet or dessert wines, some residual sugar is intentionally left post-fermentation to add sweetness and contribute to microbial stability.
The primary fermentable sugars in grapes, glucose and fructose, are known as reducing sugars due to their ability to be oxidized. The HI83746 photometer utilizes the Fehling method to accurately determine reducing sugar concentration. When a sample containing these sugars reacts with the alkaline cupric tartrate (Fehling reagents), a color change occurs. The intensity of this color change is directly proportional to the sugar concentration in the sample.
This color change is then analyzed using the Beer-Lambert Law, which states that the absorbance of light is directly proportional to the concentration of the substance. The HI83746 employs a 610 nm narrow band interference filter, allowing only a specific orange wavelength of light to pass through to the photodetector. As the color of the reacted sample deepens, it absorbs more light, resulting in a measurable decrease in transmittance and a more precise reading. The meter is capable of measuring reducing sugars up to 50.00 g/L (ppt).
