I have read that baking soda does help keep the shrimp firm, but when I tried it I had to spit them out. Even after they were rinsed, the overpowering flavor of baking soda was still there and it was not pleasant. So, I do not recommend using baking soda. Instead, I found when you cook the shrimp at 140℉/60℃ for just 15 minutes they are plump and firm with the slightest bite, and very tender. Simply put, they are perfect. So, skip the baking soda and only cook them for 15 minutes.