Chemistry Studies in Siena 2012: Red vs. White

Throughout our ventures to wineries such as the Ricasoli Castle in Brolio and La Magia in Montalcino, I’ve heard my classmates question the differences between red and white wine. Due to my “extra virginity” in the arena, I wondered about the distinctions between all types of alcohol, but I thought I’d delve into the topic of Red vs. White here.

Gathered from my search online and our field trips, it seems white wine can be made in two ways. It can either be made through the fermentation of “white” or “green” grapes, or the fermentation of red grapes with the skins removed. Both Ricasoli and La Magia described white wine production through the second method, which seems characteristic of the region.

More on the fermentation and aging process… Malolactic fermentation is carried out using yeast, bacteria (surprise!), sugar from the grapes and oxygen to convert malic acid, an unstable compound, to lactic acid and CO₂ gas. The must, or fermentation mixture, is then placed in high quality barrique barrels to age elegantly. Aging in barrique can occur over 2 to 5 years, followed by a few more years of storage in bottles to ensure top-notch quality wine is being delivered to consumers.

Temperature, humidity, light and chemical balance are all maintained stringently to ensure proper processing.

Grappa, an awfully strong, nauseating wine is made from the skins of red grapes. Surprisingly it’s a clear, manila colored liquid. How is that, you may ask? Well, the skins are run through various solvents to remove most of the chemical compounds. What go to the distillery are clear grape skins.

Wine Naming Tidbit: European wines are generally named after their production region whereas newer wine making regions name their wines after the grape variety.

There are major chemical differences between red and white wines. Red wines, because they are processed with the skins of red grapes, contain many more medicinally active chemical compounds. These include tannins, which are bitter and highly beneficial compounds (think bitter gourd, walnuts or acorns…), and phenols including anthocyanins, which contribute to the color and antioxidant quality of wines. The leading anthocyanin antioxidant is resveratrol, which is also found in peanuts!

One ounce of peanuts has half as much resveratrol as an ounce of red wine.

trans-Resveratrol

White and red wines also have pretty distinct taste differences. White wine is highly acidic. Red wine is fruitier and more bitter, contributing to the tannins.

Even so, the taste of the wine varies from year to year due to the terrior, or microclimate of grape cultivation. The goal of the Ricasoli wines is to maintain the terrior between harvests. This means having clear, clean and powerful wine with great color and minerality.

I’ll summarize the Ricasoli winemaker’s metaphor for great wine: Wines from different harvest are like sons. All 5 sons are sons. But each has his own great personality, flavor and vigor about him.