I generally think of one's willingness to try something new as a matter of either personal preference or a tendency to go outside their typical realm of comfort. Having done things like rock climbing, repelling, and a whole bunch of things that initially scared me out of my wits, I think it came to adjusting to new things.
As for food and beverage, the same applies, to some extent, due to acquired taste, or natural inclinations. Example? Mash potatoes. Can't stand them. The texture makes me feel all warm and fuzzy, and then I decide to excuse myself from the table.
Anything with that same texture, I now avoid, since I get sick in the stomach, and will just refuse to attempt other varieties.
Tried them many times, but in that particular case, I never came to like it. On the flip side, I had to gain a taste for fish, since when I was younger, I never liked it, but I cam to develop a taste for it after forcing myself to eat it.
So, the way I see things is that one's character has little to do with trying something new (either once, or repeatedly), but rather, their inclination to experiment plays a larger role from my experience.