Stag’s Leap Wine Cellars

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Stag’s Leap Wine Cellars

Winemaking Articles

What is Brix?

You may have heard the term used in winemaking and wondered exactly what Brix means. It is not a building material but it represents an important building block in making wine.

Brix is a scale of measurement used to determine grape sugar content. This information helps winemakers decide when to harvest the grapes in order to achieve the ideal balance of flavor and alcohol content in the wine that will result.

Technically speaking, Brix is a conversion scale that allows scientists to quickly correlate the density or specific gravity of a sugar and water solution into degrees of measurement. The scale is named after Austrian scientist, Adolf Brix. In the mid-1800s he used earlier scientific work based on the density of salt solutions to develop a similar scale for measuring sugar levels. The table was later refined by Fritz Plato into the scale we use today and was on the cutting edge of winemaking technology in the early twentieth century. Today, each degree of Brix in the scale represents approximately 1% of sugar by weight.

The original method for determining Brix involves using an instrument called a hydrometer. A typical hydrometer is a sealed and weighted, long-necked, glass bulb which looks similar to an old-fashioned mercury thermometer but much larger in size. The weighted bulb end is submersed in a tall cylindrical shaped flask that contains the liquid in question. The level at which the neck floats above the liquid is recorded against the markings on the hydrometer. That number is used to determine the degree of Brix. It is a handy, if fragile, instrument in the winemaking process. Other types of measurements, such as alcohol content, can be determined using the same process. Home winemakers use this method to determine if sugar should be added to wines made from fruit other than grapes and food scientists use it frequently in their work as well.

Nicki Pruss, our winemaker, monitors the sugar content of the grapes on the vine starting in late summer, sampling clusters approximately every ten days. As harvest draws closer, it may be necessary to check sugar levels as often as every three days. Sample clusters are picked from each row and brought back to the lab. All the grapes in the cluster are crushed to release the juice. The classic lab hydrometer has been replaced by modern equipment: a refractometer and a densitometer. A drop of grape juice is placed on a prism lens. The two pieces of equipment give similar readings but the densitometer is more useful for tracking sugar levels in the juice once fermentation begins. Both produce a digital reading that can be displayed as Brix.

Contrary to what you may hear, there is not a perfect Brix for winemaking. Levels between 22˚ and 28˚ Brix can be acceptable depending on the grape varietal, the terroir, the weather, and the winemaker’s style. Brix levels can also fluctuate within the growing season. A spike of hot weather sends the sugar levels up. Unexpected rainfall during harvest can dilute sugar content and lower the Brix.

Lower degrees of Brix emphasize a wine’s acidity or the mouthwatering zing of flavors we feel on the sides of the tongue. Measurements of 22˚-24 ˚ Brix are common for white wines, red varietals with high acidity, or when cooler growing temperatures are present. Higher degrees of Brix, in the 26˚-28˚ range, create jammy fruit characteristics and wines that are considered “hot” due to higher alcohol levels. Late harvest and dessert wines often hang on the vine until the Brix level reaches 28˚ or higher to develop as much sugar as possible. Stag’s Leap Wine Cellars aims to create a balanced wine with a complexity of flavors and carefully monitors the levels, aiming for a range of 22˚-23˚ Brix for Chardonnay and Sauvignon Blanc and 23˚-25˚ for Cabernet and Merlot.

The winemaker’s job requires an appreciation for art and science to create the wines we find so delightful. Luckily you don’t have to know how to use anything more extraordinary than a cork pull and a glass to enjoy the degrees of pleasure we get from an extraordinary wine.