So I know this is completely random and doesn't make much sense but hear me out and help me figure this out. We bought a half gallon of fresh squeezed grapefruit juice for our grapefruit ryePA a few weeks ago. We used about half of it and stuck it back in the fridge. After about a week or so it started to swell the milk jug type container awfully taught. That seemed weird to me and I basically thought it was souring or something. Popped it open the other day to see what was up and it didnt smell bad at all. Tasted fine so I stuck it back in there and squeezed out all the air to see what else would happen. A week or two later and it's very very tight and swollen again. Pour it into a cup and it's basically carbonated which leaves me to believe that it has fermented leaving me with some alcohol maybe? Seems pretty odd and improbable I know but I swear that's what's going on. What ABV grapefruit cider do you think I have?