1. Preheat oven to 250°.
2. Combine first 5 ingredients in a small saucepan, and cook over medium heat, stirring until sugar dissolves. Bring to a boil; cook, without stirring, 8 minutes or until sugar reaches 260° on a candy thermometer. Remove from heat; quickly stir in baking soda and vanilla. Pour hot caramel over popcorn, add almonds, and quickly coat popcorn.
3. Spread popcorn mixture on lightly greased baking sheets. Bake at 250° for 1 hour, stirring every 10 minutes. Remove from oven, and let cool. Store in airtight containers.