Their specific properties are what interests me: they can roll, float and fall, they can be filled with water, you can stand up in them, explosions make their lids fly off, they can be pumped up with steam, etc. The history of the barrel’s development is quite interesting. Initially they were made of wood, held together by iron hoops, and later of welded sheet metal with a heavy central hoop. Today they are made from one piece – out of steel, aluminium or stainless steel – and without welded hoops.

Plastic barrels also exist, but I don’t like them. They are formless, whereas metal barrels have a formal beauty about them – a body. If you knock on a plastic barrel, it sounds like a cardboard box; a metal barrel rings. I once visited a barrel factory. Barrels were being shaped out of sheet metal, then welded and painted. They were rolled on ramps, slid on conveyor belts and floated through the air hung from cranes. They were painted various colours.

It looked wonderful – like a ballet. My first barrel was red, a petrol barrel. My friend Sigi brought it to me from a garage. I buy my barrels in Spreitenbach near Zurich but they come from Germany. There used to be a barrel factory in the Canton of Basel. There was also a barrel recycling company near St. Gallen. My wife Aleksandra shot a beautiful film there. The barrels were steam-cleaned, painted and inspected. When a barrel is damaged, I take it to a scrap metal dealer.

The barrel in the photograph is an ordinary metal one. It’s a new barrel that I haven’t used yet. I like to use blue barrels – Gentian blue – and always the same ones. There are different kinds of barrel. Open barrels with a lid and closed barrels with a bunghole. I have only twice used a red barrel. Blue, open-topped barrels are used for all manner of things, not just for liquids. Sometimes wooden barrels are still used, say, for coffee. In Scotland I once saw a pyramid of whisky barrels. I always have a barrel in reserve at home. Even if I don’t do anything with it, I find it beautiful. It has a pleasing, standard design. As far as I know, barrels are the same size the world over.