[RubyO (OP)]

Mike has this tasty question:

I'm originally from the Dominican Republic, but I emigrated to the US. When I came here, I tried my first canned soup ever. I immediately noticed that cann-y taste. Over the years I've kept wondering the reason for this. Recently, I tried to make soups that taste as close to a canned soup as possible. I canned 4 batches in mason jars, and to take into account for the can itself I made one can with no metal, I put a piece of steel  in one can, a piece of aluminium in another can, and two pieces of steel and aluminium in another can. While the cans don't taste great, they don't have that characteristic cann-y taste. Is there a reason for this? (Also, I took into account preservatives).

Can anyone help?