(WineFolly) - Brix (°Bx) is a way to measure the potential alcohol content of a wine before it’s made by determining the sugar level in grapes. Each gram of sugar that’s fermented will turn into about a 1/2 gram of alcohol. Of course, different winemaking techniques will affect the final alcohol content, which is why Brix is interesting to us inquisitive wine explorers.

Brix Measures Alcohol Potential

Brix correlates to the potential alcohol content of a dry wine. If everything ferments perfectly at the winery, the Brix-to-alcohol chart looks like this:

Alcohol content is determined with an alcohol conversion factor of 0.59 and rounded to the nearest tenth. It’s common to see conversions from 0.55 – 0.65 depending on grape type, yeast strain, data collection error, etc.

The Secrets Brix Can Tell You about a Wine

 If a Wine Has Lower Alcohol than the Brix Scale Suggests

WINE WAS ‘WATERED BACK': If the wine is dry and has less alcohol than the Brix scale suggests then the wine was most likely ‘watered back’ during vinification. ‘Watering back’ simply means some of the sweet grape juice is drained off and replaced with plain water. The leftover pink-tinted grape juice is used to create a rosé wine called Saignée. This technique is commonly practiced in warm climate regions where grapes become very sweet by the time they’re ready to be picked.

WINE IS SWEET: Another possibility is that the wine is sweet! For example, German law requires that all Spätlese Riesling wines have a minimum Brix level 20, but many of the wines only have 7.5% alcohol by volume (ABV). In this example, you could assume that the wine would have about 75 g/L of leftover grape sugar, called residual sugar (RS). By the way, 75 grams per liter RS is equal to about 3 teaspoons of sugar per 5 ounce (150 ml) serving.

 If a Wine Has Higher Alcohol than the Brix Scale Suggests

WINE WAS CHAPTALIZED: If the wine has higher alcohol than the Brix scale, then it’s possible that the winemaker added sugar or concentrated grape must to the fermentation to get the wine to have a higher alcohol level. This technique is called Chaptalization and it is commonly practiced in cooler climate countries such as France where it’s very hard to ripen grapes properly.