1 bottle of fruit juice , ¼ tsp (1 oz) champagne yeast

Pour out 2oz of juice from the bottle (to prevent overflow during the fermentation process).
Mix the yeast into the juice.
Top with an airlock (or balloon) and allow to ferment somewhere warm for 3-5 days.
Ferment to taste (it will become less sweet and more alcoholic as time goes on).
Replace the original cap and store in the fridge. Release pressure built up in the bottle every few days as needed.
Notes:If you want a sparkling drink, cap it after three days, and put it in the fridge so that the carbonation can build up.
This is not the sort of thing that improves with age, so drink it when it tastes good!
I used a hydrometer (to measure alcohol content) and did some experimenting with my brews. This is what I learned:
It took five days to come close to full fermentation.
Without any added sugar, the maximum potential alcohol content of the juice was around 3%. The maximum potential alcohol content went up as I added sugar. I was aiming for about 5%, and that was around 3 tbsp of sugar (but it would depend on the natural sweetness of your juice).
I really liked the juice hooch. It was so drinkable. Because I capped it off before all the sugar was used up by the yeast, it was sparkly and still sweet. However, there are a number of factors that could affect the flavour. Including: your choice of juice, yeast, sugar content, and length of ferment. It is a cheap and fun way to experiment with DIY alcohol!www.rayis.me