Ever since after a month-long overseas trip to France I returned to find that a rat had taken a particular liking to six bottles of 1916 Chateau Coutet, gnawed away the lead capsule and then as much as it could reach of the cork, before pushing the remainder of the cork into the bottle with its nose, I have conducted more or less continuous warfare against rats in my cellar.
It has never occurred to me that screwcaps might be subject to rat attack. Ken Helm (firstname.lastname@example.org) has sent me the following email, and photographs of the damage caused to screwcapped bottles in his cellar. Amazing!
Rat in the Racks May 4 2010
Rats attacking the screw caps on wine bottles, in wine racks, have been noted by Ken Helm of Helm Wines in Murrumbateman. The cold wet weather at this time of the year, forces rats and mice to seek shelter in buildings, and a cellar can be very attractive for them. This has uncovered a problem as yet not reported.
It seems that Rats like to chew the tin foil of screw caps which can result in loss of valuable wine (see photo). The damage can be expensive, and Ken recommends precautions be taken, by collectors who have their cellars in garages or under the house which is open to rodent occupation.