100 Days Project

Nanogirl: Star Science

Nanogirl wants to find 100 friends to do science experiments with her to prove that no matter who you are or what your education level, you can always have fun with science.

Day 36:

Wine scientist Gerard teaches me about wine

Today while at the airport I bumped into one of my favourite people who also happens to be the best wine scientist I know.

Gerard is a wine scientist who is about to get his doctorate in the field. I asked him if he had a wine experiment he could show me, and luckily he did.

Taking a glass of red wine, Gerard added a few drops of lemon juice and I watched in amazement as the wine changed from one red hue to a more transparent less red wine.

Asking Gerard why this happened, he explained that the reddish color seen in wine is mostly due to the proportion of a chemical group called anthocyanins. This is group is dependent on the acidity and free sulfer dioxide concentration.
High acidity increases the proportion of anthocyanins in a state called the flavylium state, making the color a more vibrant red. As the acidity of a wine decreases, the percentage of flavylium anthocyanins decreases, so by decreasing the pH using acidic lemon juice we were able to watch this happen through the colour change.