I have had some problems recently with some of my wines developing a harsh flavor due to oxidation. Today I took a bottle of cheap grocery store sauvingon blanc out of the fridge to use for cooking. It had been opened and in the fridge for 2-3 weeks, so I tasted it to see if it was still good enough for cooking. To my surprise, it did not taste oxidized at all. With both my own wines as well as commercial wines, I have found that some taste oxidized 24 hours after opening, while others last several days in the fridge without a significant oxidation flavor. Why?
Apparently different wines have different anti-oxidant potential. Part of that is the level of free SO2, but I suspect that other antioxidants such as tannins and polyphenols also play a role. So I decided to do a little digging, and discovered a few things that I found quite interesting:'
Apparently different wines have different anti-oxidant potential. Part of that is the level of free SO2, but I suspect that other antioxidants such as tannins and polyphenols also play a role. So I decided to do a little digging, and discovered a few things that I found quite interesting:'
- Ethanol oxidizes to produce acetaldehyde, which is the cause for the slow burn at the back of the throat.
- Yeast naturally produced acetaldehyde in the exponential growth phase, and uses some of that to produce ethanol in later stages. Under proper conditions, most of it is converted to ethanol before the end of fermentation.
- Sur Lie produces a reductive environment, which can decrease the amount of acetaldehyde: https://real.mtak.hu/49702/1/066.2017.46.1.14.pdf In this article, it is apparent that 60 days of sur lie can significantly reduce levels of acetaldehyde, even with 0 free SO2.
- MLF bacteria can also reduce the level of acetaldehyde: https://admin.lallemandwine.com/wp-content/uploads/2013/07/WE5-USA.pdf
