Fermentation often is considered as something demanding years of experience and some mysterious knowledge. For all thinking this way I dedicate the following recipe:
4 litters of non-preserved apple juice leave out at room temperature. Cover the top with the kitchen towel or mesh to keep flies out but give yeast access. Wait till the juice will turn into cider.
Meanwhile elsewhere: this is how prepared yesterday sourdough starter is doing:
apple juice cider days left to stwst48