Buy a big bottle of apple juice, remove about 50ml, add half a teaspoon of yeast, replace the top but allow it to be just loose enough to allow the carbon dioxide to escape. Within four days or so, the apple juice turns into a reasonably acceptable cloudy cider strong enough to make your knees dissolve.
Al Marai apple juice works very well indeed. It's important that the apple juice contains no preservatives, or the yeast will be killed off and the mixture won't ferment.
Curious as to quite how alcoholic my home-brew concoction actually was, I borrowed a hydrometer.
The latest batch, using 'natural, preservative free' apple juice from Nadec produced an alcohol by volume of exactly zero. Oh dear, that wasn't in the plan. I added sugar and more yeast, and set it off again. It bubbled, but sadly produced no alcohol. The mix tastes sweet, suggesting that the yeast isn't metabolising the sugar into something more useful.
There must be something in Nadec's 100% apple juice that prevents the fermentation process. It's not listed in the ingredients: Purified water, natural apple juice concentrate, vitamin C.
I'm going back to Al Marai, if I can find some.