To taste several similar dishes or foods and compare them (flavor, texture, etc.).
ケーキを何種類か買って食べ比べてみた。
I bought several kinds of cakes and tried comparing them.
地元のラーメン店をはしごして食べ比べるのが好きだ。
I like going around local ramen shops and comparing them.
このソースは辛さを変えて食べ比べると違いがよく分かる。
If you compare this sauce by trying different spice levels, you can clearly tell the difference.