Tins of corned beef and sardines.

Why do tins of corned beef and sardines have those little key things to open them?

Or maybe my question is, why are they the only tins that have the little key thingys?

WAG, but those cans are square; conventional can openers would have trouble getting around the corners.

I do recall seeing round cans that required a key. I think it was a can of condensed (or evaporated) milk. The can was constructed without the lip that a can opener would grasp onto.

I have no idea why, though.

What do you mean by “little key thing”

I’ve seen a lot of cans (fruit, tuna, tomato puree etc) that have a tab on the top that you can use to open the can without a can opener.

Yes I know many cans have the ring pull thing but the key thing is different. Its a t-shaped gizmo with a little slot in it. The tin has a little tab on it and you put the tab into the slot and then wind it. On the cornbeef it winds off a small strip of the can about an inch down from the top of the can.

postcards you may be right in thinking it is about the shape of the can.

CAnned Spam used to have this, but has since switched to a pull tab. The old version was described thusly:

I have a canned ham that uses the key. I think in the US that’s about all that uses it anymore. It uses it because of its shape.

Most cans of ground coffee used to come this way, back before the dawn of recorded history that is[1950’s and 60’s]

The raw metal edge left by these things are deadly. You can easily slice the top of your finger off. I have noticed that some corned-beef and sardine tins have now gone over to ring pulls , much safer.

Some more thoughts on this subject. Here in the UK ,at least, most of our corned beef comes from South America ( there is an actual town called Fray Bentos in Uruguay ! ) and sardines come from countries such as Morocco . Could it be factories in these countries cannot afford to buy new machinery to enable their products to be packed in conventional tins, including those with ring-pulls?

As mentioned, canned hams (which I buy at Costco) are the only cans (“tins” to you Britishers) that I’ve seen with that keyslot thingy. Most of the time I could not get it to open correctly; it will usually wind around the key crookedly. Moreover, I once cut my finger trying to get it to wind properly. So, I ususally resorted to the can opener anyway. There is a can opener now that does not create any jagged edges. It cuts around the outside of the top, and the top just pulls away from the can without any edge with which to cut you. Can be used on any can.

Anchovy and sardine tins might have been worse when they used to use those things - the key wound off the top of the flat can, rather than taking a strip of metal off around the side of the can. In addition to slicing your finger on them unwinding them, they left just enough of a lip around the top of the can that you had to poke at the can to get the fishes out, and because you wound up with a wide shallow can open at the top, you sloshed oil or salt water all over the place in the process because it was hard to keep the stupid can perfectly flat during the operation.

Some of those problems still exist with the pull tabs, which still remove the whole top of an awkwardly shaped flat can. Somebody needs to rethink how they package small fish.