As I was digging into making my own British bangers for my Full English Breakfast challenge, I kept stumbling onto the same sad story which may or may not be complete bullshit: During the early 20th century thanks to two World Wars, meat was scarce in England and pork sausages were padded with some grains and extra liquid to help stretch the meat reserves. When cooked, these padded sausages had the tendency to burst out of their casings and the "banger" was born.
Exploding sausages! How cool is that?
Though this tale may be made up, it oddly shines a light on one aspect of the banger--besides the exploding part--which turned out to be absolutely essential: filler. There are stories about percentages, discussion on what kind of cereal to use, and cautionary posts about other nefarious ingredients that are included, but the case remains the same: Bangers must have filler or they simply aren't bangers.
Even famed British chef Heston Blumenthal seems to agree. In his book and TV show, In Search of Perfection (check out the episode on Youtube) he sets out to create his perfect banger. At first he figures that the sausages should have no filler at all, just meat and seasonings. But the results seem to sever the tie with the sausages of his youth--his 8 year old self that cooked sausages over a campfire. The filler-less sausage may taste great, but it doesn't taste right. Heston eventually embraces the filler to a uniquely obsessive level (let's just say that toasted bread water is involved).
So for my bangers, I knew I needed some filler of some kind, and I figured that breadcrumbs would be the logical choice. But what was most fascinating was that the many recipes I found called not for breadcrumbs, but for rusk. And thus a new question was born: What the hell is rusk?