me to belive alicorn are immute to alcohol! i belive celestia is the first to fond out! why? well first i think she never drink one of her live and say no everytime the noble give some to her! but the day she seal her sister she want to be drunk to forget her sadness but is not work! i think celestia a not want to tell it to twilight is learn by her self what a alicorn do and all thier power! and this night twilight learn alicorn are immute to alcohol! i think twilight as a unicorn she only drink max 6 boc of alcohol apple cider! the % of alcohol is unknow of the alcohol apple cider are by! and i dont know the limit of every twilight friends can drink but one thing is sure is her will take her friends home!