Making a better caramel for granola bar I came up with a recipe of granola bars where I melt 


10 tbsp of brown sugar
4 tbsp of honey
4 tbsp of soy oil
2 tbsp of water
Vanilla extract


and mix with 4 cups of rolled oats + 1 cup of rice crispies, put it in a pan and bake it for 20 min at 200ºC/330ºF. After cooling, I get a nice and firm granola bar for about one day, after that the bar gets soft and starts crumbling.

How can I adjust my recipe to make my bar more solid and for longer?
If it stays the right texture for the first day, I would say the problem is more with the way you store it than the recipe. Granola bars need to be stored in an airtight container, somewhere dry and cool to maintain their texture for as long as possible.