So I am attempting to make my own hard cider. At my school, there is a farmers market every Thursday and at this market they sell flash pasteurized cider; the process is stopped partway through so it is clean to drink but can still ferment. Anyways I have tried (with success at about a gallon per batch) to create hard cider simply by pouring the cider into bottles, stopping the bottles with cotton balls, and leaving them in a dark corner for 4 days. In that time they fermented (smelled like yeast and alcohol so at least I think they did) so I filtered them, mixed them into a big pot, brought the mixture to 160-180 degrees, and then chilled them.
During the last batch, one bottle had a dry white collection (looked almost like baking soda) resting above the bubbles. I mixed it with the batch anyways; is that safe? Should I toss out the batch? I drank it last night and feel fine, but what do you think it was?
Also the past two batches have tasted great but tend to be very very weak, bringing me to another question: if I add yeast, say champagne yeast, before I let them sit, will this increase my alcohol yield? Also, should I add sugar with the yeast? The concoction is still very sweet with the above mentioned method.