Alcoholic beverages and some low-polluting gasolines contain ethanol, CH3CH2OH. It is generally considered less corrosive to metals than methanol, CH3OH, the alcohol used in race cars.
Metals Handbook, 9th Edn, Vol. 13, Corrosion, p. 688 mentions studies have reported that anhydrous ethanol (not a usual grade, CP-grade is 95% with 5% water) may cause cracking of &[ignore]alpha[/ignore];-&[ignore]beta[/ignore];Ti alloys such as Ti-6Al-4V. This corrosion may be prevented by the presence of H2O.
Corrosion Engineering, 2nd Edn., has a table (p. 434) which reports that boiling ethanol attacks Al; the pitting may be prevented by 1% H2O. Also, ethanol in the presence of halides (e.g., Cl-) attacks steel and cast iron. Dearation and elimination of chlorides prevents the attack. So, stay away from 200 proof stuff and any salty wine!!
From personal experience, I know that California wineries have any aluminum in processing rooms, e.g., light fixtures, plated with electroless nickel. This is probably due to organic acids and/or cleansers, though, as ethanol is not present at this stage.
Wine alcohol isn’t entirely ethanol; it also contains some polyalcohols (2 or more OH’s per molecule, longer C chain length):
“The most important alcohol in quantity is ethyl, a monoalcohol. Then comes glycerol, a polyalcohol that adds a degree of sweetness. Butylene glycol is among other polyalcohols and cyclic alcohols present. In some fortified wines, alcohol attained by distillation may be added.”
As your question concerned the corrosion, my opinion is that the corrosiveness of wine toward aluminum is mostly due to the numerous organic acids (e.g., tartaric, malic, citric, succinic, lactic and acetic) plus minerals (potassium, calcium, magnesium, sodium, iron, sulphates, phosphoruses), and odorous substances (aldehydes, esters and ketones in addition to the previously mentioned alcohols and acids) plus sulfite. Also, phenolic compounds. Nearly 1000 compounds have been identified in wine, see above and following links:
‘Corrosion of Aluminum in the White Wine’ [probably in Japanese, with English abstract], by Yoichi Kojima (Department of Metallurgy, Univ. Tokyo), Zairyo-to-Kankyo, vol. 45, 5 (1996) published by the Japan Society of Corrosion Engineering (JSCE).
Have heard that wine contains anti-oxidants beneficial human health, but w.r.t. aluminum, these may be detrimental to the passive oxide film.
Conclusion: wine and other beverage (soda, beer) components which corrode Al, which is why all beverage cans have some sort of internal laquer coating. In the case of wine, alcohol may work with in combination with other components to cause corrosion. In any event, once opened, it is best to ‘drink up’ your wine to avoid acetic acid formation.
