Stupid question from a non-native speaker: what is the difference between apple juice and apple cider? In my mind, you ferment juice to make cider, but the article calls the initial raw liquid coming straight out of the press "cider".
Cloudy apple juice is referred to in the UK, and most places apart from the USA, as "cloudy apple juice". Cloudy fermented apple juice is referred to in the UK as "scrumpy" or "scrumpy cider". It's mainly made in Herefordshire and the West Country, and it can be surprisingly strong; in many West Country pubs, they won't let you order a pint of scrumpy, they'll limit it to half-a-pint, unless you are known (or have a local accent).
I have heard, but I don't know, that it was customary to chuck an iron ploughshare into the cider fermenting vat; it would completely disappear by the end of fermentation. I have heard a similar tale about throwing in a horse's head - nothing left, dissolves completely.
I'm sure they don't use these adulterants in the production of commercial "hobo cider", such as White Lightning. But vegan "ciderpunks" should maybe ask questions about the scrumpy they are ordering.
I have trouble believing that this was customary. It's absolutely the case that iron will dissolve in a large vat of fermenting apple cider, but the result will be a cider with some very odd and unpleasant colors and flavors. Not something that someone would want to induce intentionally. Most cidermaking books will instruct one to keep the cider from any contact with any iron, copper, or lead as all three will readily dissolve.
It sounds like a bonkers tale to me (which is partly why I related it here). I've never tried to make cider, and I've never read a cider-making book. It certainly doesn't sound like the kind of hygiene practice that is normal in fermenting processes. But I do have the impression that hygiene is not taken as seriously in cider-making as in, for example, beer-brewing.
Beer, by contrast, is boiled for an extended period of time prior to fermentation. This gives a sterile starting point, but doing something similar to cider will radically change the flavor.
Especially with scrumpy; it often (usually?) tastes pretty vinegary - not like commercial cider at all. I think it's much more refreshing and thirst-quenching than sweet commercial cider.
I like to cook with cider vinegar. It's refreshing, and relatively sweet. I'd say the difference between cider vinegar and scrumpy really comes down to a matter of degree.
It's surprising that vinegar is refreshing; but roman soldiers used to carry sour wine (vinegar) with their equipment.
And when a roman soldier (supposedly) passed a cloth soaked in vinegar to Jesus on the cross, he was passing him the most-refreshing thing he had - it wasn't some kind of sarcastic taunt.