I haven’t seen anything which would suggest that skin and seed tannin have different reaction rates. The published chemistry is that skin tannins are larger molecules than seed tannins. As tannins age they form larger and larger complexes and eventually get large enough that they are insoluble, fall out of solution and then are tasteless.1. skin tannins react more quickly with oxygen than seed tannins.
2. skin tannin content of wine is higher in uncrushed grape wines than crushed grape wines because they ferment more slowly due to lower pulp surface area.
2) molecules tend toward equilibrium with their surroundings. If I have uncrushed grapes the concentration in the berry pulp will already be in equilibrium with that in/ on the seed. A guess is that the flavorful polyphenols are part of the skin on the seeds. (with rice, corn and wheat the interesting polyphenols are skin related ~ endosperm is primarily starch with 10 to 15% protein, fat, mineral)
Aroma can be both a positive and a negative. Reductive flavors / reduced sulfur can be detected down to 0.2 parts per trillion/ H2S is detectable down to 1 ppt. In comparison fruity aroma compounds are detected at parts per million. (ie one could smell a drop in a basketball gym vs one drop contained in a bathroom)4. oxidizable aroma molecules are semi-protected by skin tannins which compete for oxygen, so the open bottles smell better longer.
Once fruity notes are lost we can’t get them back. Reduced sulfur is powerful enough that it will overpower our ability to sense fruityness, ie we think it isn’t there. If the reduced sulfur (reductive flavor) is exposed to oxygen it oxidizes to a less volatile form which isn’t masking the fruity notes, so we think it appeared again. The winemaker is manipulating a reduced chemistry soup, he will have choices as how much and which antioxidants are used, how many mg of oxygen the cap is rated for, do they nitrogen flush at filling, do they nitrogen flush the pipes from tank to filler, etc. Minimizing oxygen is advantageous if producing country wines with low tannin (antioxidant). Micro oxidation is useful if one has a highly tannic wine, basically a lot of the polyphenols don’t taste good. Oxidation can be used to convert the tannin into a flavorless form. Excessive oxidation pushes the soup such that more energetic reactions as creating acetaldehyde happen simultaneously with lower ReDox potential / easier reactions as oxidizing tannin or aromatics.
Temperature as refrigerator 2C versus cellar 10C vs room 18C won’t push oxidation a lot. It will affect how volatile fruity aromatics are. In warehouse storage the key is daily variation. Each cycle down draws oxygen through the cork, vs warming expands the trapped gas exchanging consumed molecules.
Oxidation chemistry happens, ,,, ex peroxides form as light strikes a molecule. A squeaky clean bottle without micro oxygenation via a natural cork will reduce sulfur changing the state to create reductive sulfur flavors. . . . . We are artists, only the university folks have the tools to measure what happened in this year vs last year’s lot. A lot of the chemistry we can taste.