I have an old bottle of wine vintage 1961which has been stored in a wine fridge. It developed mold on the surface of the bottle which I was able to wipe off. On the foil however I noticed a white substance that appears to resemble a crystalized salt. What might this substance be and how do I clean it off the foil with out damaging the foil?
Answer From Expert Roger Bohmrich MW
Deposits of various origins are not uncommon with old wines. If there is a residue around the capsule, it could indicate there has been a leak. If the deposit is dark in color (and possibly sticky to the touch), wine may have seeped from inside the bottle, implying that the wine has been exposed to oxygen. On the other hand, a white salty substance could orginate with a metal capsule. Lead was commonly used in capsules for many years, and lead salts can be found beneath or on top of the closure. All factors considered, my suggestion would be to consume your 1961 in the near future - unless, of course, you have other plans. 1961 was a fabled vintage in some classic regions (Bordeaux is one) and certainly is of particular interest to collectors. If you intend to drink the wine, cut the capsule below the lip of the glass and clean the top thoroughly with a damp cloth before and after you pull the cork to be sure that no deposit remains.