Question

why did german immigrants come to America? What types of foods and snacks did they bring with them that we consume now?

Answer 1

 Mostly because of religion. There was a lot of conflict between Catholics and Protestants. Now some of the food that they brought with them should be things like hamburgers because that is actually a German dish that Americans seem to enjoy so much; I would expect sausages too. 

Answer 2

Many of them came over because of the civil unrest they were facing in Germany. They brought over the hot dog (or frankfurter), the hamburger, sauerkraut, and sauerbraten.