I have known for months, maybe even a year, that a tin of tuna had fallen down the back of the cupboard. It was only when a tin of sardines followed it, and got stuck on the way, that I finally pulled everything out to save them. In return, they saved dinner.
Putting fish in a tin is a sustainable act (in principle, anyway), because it gives almost everlasting life to a product with an extremely short shelf life and an extremely high risk of waste. Another thing about tinned fish is the deep umami flavour that can develop during the curing and canning process (especially when the fish is preserved in a good-tasting brine or oil), which is not only deeply delicious, but thrifty, meaning that a small amount goes a long way. However, both these things depend on countless tangled factors. It is at moments such as this when I imagine I am Hattie Ellis at the beginning of her book What to Eat (which I am on a mission to see updated and reissued), standing in a shop and staring at the shelf, overwhelmed by “Sticky questions about food” and thinking, “Which tin should I choose?”
