No way this recipe makes 20 popcorn balls. Think about it - 18 cups of popcorn - that is not even 1 cup per ball. Then they get wet from the syrup and packed together. I got 8 and they were not that large. That being said, they were delicious.
Our family has used this recipe for 75+ years with two minor deviations - but that might make a difference for everyone! We use 20 cups of popcorn instead of 18 cups. We also use an extra 1/2 cup of water (one cup plus 1/2 cup total) everything else is identical. The trick for us is hitting the temperature exactly on the nose of 250 - not a degree higher or lower!! Hope this may help some of you who are frustrated with the recipe- It is a holiday tradition for us and the whole family loves them!
2 stars, I got 20 small (2-3 inch) popcorn balls that tasted OK. The syrup, when cooled, had a crispy "bite", but they were very fragile & I had a hard time getting them to hold together. I don't know if I used too much popcorn (probably close to 6 quarts, in retrospect) or didn't stir well enough or what. I know it wasn't because of cooling, because I had the problem w/even the first few that burned my fingers! It took me about 40 minutes to get the syrup to 250/hard ball stage, but it didn't make the popcorn soggy. Next time I'll make marshmallow based ones, much easier to work with.