Biochem student question.

[Alex Becket]

I am a biochemistry student at the University of Cincinnati. I am doing a
study of the relative hydrophobicities of amino acid side chains. My
question is:  does a larger surface area available to water increase or
decrease an amino acid's hydrophobicity? For example, tryptophan has a
larger surface area available to water than phenylalanine, yet phenylalanine
is more hydrophobic (unless using long chain alcohols as the nonpolar
phase).

any response would be greatly appreciated.

--Alex