Combine the above in a 2-qt. saucepan, bring to boil (stirring to dissolve sugar completely). Continue boiling and stirring until syrup thickens and reaches the "hard-crack" stage -- consult the candy-making section of any comprehensive cookbook for description and candy-thermometer temperature. My method of determining readiness is when the syrup "makes threads" when dropped off the tip of a spoon OR when a drop allowed to fall into a cup of cool tap water forms a ball instantly. It takes practice -- cook too long and the coating will be granular; cook not long enough and itll be sticky. When the syrup reaches the desired stage, take it off the burner, IMMEDIATELY stir in 1 teaspoon vanilla and 1/4 teaspoon baking soda (the soda interacts with the vinegars acidity and makes the syrup light and sort of foamy). Pour gradually over popped corn while stirring with a long-handled spoon to distribute the coating (or have someone else do the stirring or pouring). This stuff is VERY HOT and will stick to you and inflict deep burns so be careful! Homemade caramel corn is much superior to anything you can buy in a package. Or at KarmelKorn, for that matter. Once you know how to do it, you can play around with other flavorings, like Cinnamon Oil (use sparingly!) or other extracts. Source: generic Posted by "Mary Morrison" to the Fatfree Digest [Volume 15 Issue 21] Feb. 21, 1995. Individual recipes copyrighted by originator. FATFREE Recipe collections copyrighted by Michelle Dick 1995. Formatted by Sue Smith, SueSmith9@aol.com using MMCONV. Archived through kindness of Karen Mintzias, km@salata.com. 1.80? File ftp://ftp.idiscover.co.uk/pub/food/mealmaster/recipes/fatfreex.zip