title_body: Recommended fermentation time for cider
upvoted_answer: The recommended primary fermentation time for anything you're going to bottle is: until it's done.
  
  After 2-3 weeks, when you think it's ready, use a wine thief to pull a sample to test with a hydrometer.  Record that number.  Then wait maybe 3 days and do it again.  Compare the new number to the first number.  If they're the same, you're safe.  If they're at all different, give it another week then repeat the whole process.
  
  The premeasured bottling sugar or bottling sugar calculator assumes the cider is completely done fermenting, if it's not then you've suddenly overdosed the bottles with sugar which could result in an explosion.