"What do I do with the food my baby doesn’t eat? I don’t want to put the jar back in the fridge after her spoon has been in it."
Kids are the ultimate food wasters.
Right now both you and the baby are figuring out what your child likes and doesn’t like, and there will be a lot of trial and error. She’s building a new relationship with food, and hopefully it’s a healthy one, so I don’t recommend forcing her to finish the jar if she doesn’t want it.
Luckily, babies can’t waste more than 4 oz of food at a time. You can also pour half the baby food in a separate bowl so you never toss more than 2 oz.
What I did, personally, is I made my own baby food. (At least, that’s what I did with the first one. Daughter #2 would not eat mashed up food.) I used to brag that my baby food was so good, even an adult would eat it. There wasn’t much waste because I’d finish off what she didn’t want.
I had lots of reasons to make homemade baby food: