When an air press is used to extract the juices from white grapes (so as not to crush the skins, and thus release their polyphenols), the oxygen in the air oxidises ~2/3 of the single ring phenols, the cinnamates. White wines without a reasonable concentration of antioxidant phenolics can cause health problems for people who drink only such white wines.
In San Michele al Adige, close to Trento in Italy, there is winery (Pojer & Sandri) where one of the partners (Marto) reserves a section for researches on wine production: the results are monitored by Dr. Fulvio Mattivi; a wine scientist, who works at a nearby Italian research institute - also responsible for verifying the DOC applicability to Italian wines.
Marto has developed a recycling gas press, using Nitrogen, which allows the preservation of the majority of the white wine antioxidants. Such a wine has ~3 times the concentration of the phenolics in airpressed wine. The good news is that his first wine produced with this technique is very good indeed. As senorially evaluated by Dr. Mattivi, this author and his wife. Other wine makers should note!
By Gordon J. Troup, G.J. Troup, School of Physics & Materials, Engineering, Monash University, Victoria 3800, Australia.