Make sure your container is clean, dry and ideally sterile before starting.
Fill your jar with feijoa skins. Try to pack them down within the jar so they are nice and firm. Sprinkle with sugar and top with water until all your feijoa skins are completely covered.
Some of the not packed in feijoa skins can start to float. The challenge is to find something that you can clean properly that you can use in your jar to weigh down the skins. If you have filled a jar which narrows at the top you use something like a glass, then put more water In the glass to weigh it down more.
Cover lightly with cling film or a tea towel. Leave to warm, dry place, such the kitchen or laundry bench for two to three days or until the water starts to turn cloudy and may start bubbling. If the water is still clear you can leave it for another one to three days.
NB Watch your skins carefully. If they are showing any signs of mold (usually little black and grey specks of filaments around the edge) you will unfortunately need to discard the whole batch and start again. The main cause of this is skins stick up out of the water, so its important to make sure they are well weighed down.
Tip the first fermented water into a large bowl and strain off all the feijoa skins.
Add the extra sugar and wine yeast if using and mix well.
Pour into clean pressure proof bottle and leave in a warm dry place for another two to three days.
Optional: chill in fridge for a few hours or serve at room temperature.
CAUTION: the pressure may have build up considerably in the bottles by this point, especially if added the extra wine yeast. You can get an idea of this by how bubbly it is around the top of the liquid in the bottle. I recommend using gloves, covering it with a tea towel and holding it over a sink or large bow. You may need to crack the lid, then hold to down to release some of the gas inside without all the liquid inside bubbling out.
To serve pour into a glass, taking care not to pour out the sediment at the end.
If you leave it in the bottle at this point it will continue to ferment and become more alcoholic If not drinking immediately I recommend storing in the fridge for up to two days. Beyond this I find its not drinkable straight away and will need to be aged to make it nicer to drink again. Ageing is a whole different ball game and more akin to making traditional cider.