BJ42 wrote:

> What exactly is vodka supposed to do to a tomatoe sauce?
> How does it change it?

That's an interesting question.

I was watching Lidia's Italian Kitchen a few weeks
ago, and she was making a sauce with vodka in it.
She commented on how the vodka itself has no flavor
and the alcohol gets cooked out of the sauce,
so she wasn't sure what it was doing, but that it does
make a difference.

One possibility is that a little alcohol from the vodka
remains in the sauce and in so doing is contributing
to flavor. Even if the sauce is heated above the
boiling point of alcohol, a significant amount will
remain behind without evaporating.

But I think it is more likely that the alcohol is acting
as a solvent, allowing flavors to meld that otherwise
would remain separated. It could be extracting
flavors from solid ingredients into the liquid, then
evaporating away but leaving the extracted flavors
more uniformly spread around in the sauce. This
could have a dramatic effect on the flavor of the sauce.