Now I'm back home, here's my cider method.
Things you need.....
A homebrew airlock with bung.
Cider yeast from homebrew shop.
Maybe a couple of cable ties.
Apple juice,
Sugar.
Soda Stream (or bottled soda water).
I use Presha apple juice, it's cold pressed pink lady apples (not sure if available in UK). Any apple juice will do, but make sure it has ZERO preservatives in it. Made from concentrate is fine too, but again ZERO preservatives. You want a 2L bottle as the small bung and airlock fits in nicely/
1) Pour a small glass out 200 - 250ml, than add 100g of sugar. Put the top back on and shake until sugar dissolved.
2) Take lid back off and add 1/2 teaspoon of cider yeast. Put lid back on and give it a swirl (no need to shake). Trying not to get yeast stuck on neck of bottle.
3) Pour a bit of boiling water over the bung. You can use a sanitiser (a few drops in a bowl is enough).
4) Take the top back off and store. Replace with bung/airlock.
5) At this point it is wise (from experience) to use 2 small cable ties. Make a loose loop with one around the lip at the top of bottle neck, then feed the other through that loop and over the bung, the tichten both up. It's just to hold the bung down firmly.
That's it. Place in a semi warm dark place. I'm in the tropics, so I went for the coolest place. Within a couple of hours it will start fermenting. Leave it for around week. After this time the airlock will have totally stopped bubbling. If it's still producing the odd bubble, leave it for another day or so. It should also be visually clear.
Now take it back ot the kitchen. Snip the cable ties and remove bung. Pour boiling water over the original top which your stored, (or dip in sanitiser solution) and screw top back onto bottle.
Place in fridge. I put it in the door shelf where the milk goes.
The coldness of the fridge crashes the yeast (kills it) and it sinks to the bottom. Over the next 48 - 72 hours it will become very clear.
You now have flat cider around 6 - 8% ABV. Depends how much sugar you add (the 100g will give around 6.5% ABV). No sugar added will give you around 4%, so only 2% when diluted and probably be very dry. Likewise, if you add 200g of sugar, you'll be up around the 9%ABV (diluted 50/50 to 4.5%). See next paragraph for dilution.
When you want a glass of cider, pour carefully from the bottle so as not to disturb the yeast (it tends to clog up the indentation in bottom of bottle and hold/solidify there well) and fill glass to around half way. Fill your soda stream bottle up with chilled/icy cold water and give it a real good blast, get lots of Co2 in (make it fart 2 - 3 times). Top up glass of flat cider with soda water, job done, you've got 3.5% crisp cider. If you want stronger cider, I would suggest adding more sugar initially, rather than using less soda water, as you want that fizz in the final product.
Instead of addign sugar, I have used blackcurrent & blackberry concentrate (preservative free), also rose & elderflower concentrate, as these are sugar based syrups they can be used to replace the adding of sugar. Have also used coffee sugar which came out well, had a nice bite to it.
As it's easy to prep, I used to make 3 at a time (6L) and keep in fridge. It was nice having a selection to choose from too. It stores in fridge for a good while and the flavours slowly develop as well, but it's good to go after 48 - 72 hours in fridge (10 days from start).
If you like cider, I couldn't recommend this method more. Adjust volume according to consumption. Works out very cheap (cost of apple juice basically). There's also something very nice knowing you made it and playing with different sugars and syrup concentrates. Just avoid any preservatives at all cost, as they kill the yeast and it simply won't work.
Cheers.
