Hi rbodell,
The top layer is vegetable oil. It's viscosity should still be the same except for any fats that may have separated into the middle layer.
Water and veggie oil do not create a chemical reaction when mixed and shaken.
They simply separate apart later. The water may help to wash out some impurities, but the result is still veggie oil and water.
As far as I know, there is no short cut (yet) for going through the chemical cracking process of mixing sodium hydroxide (or potassium hydroxide) to strip off glycerin and add (bond) carbon molecules in the biodiesel reaction process.
Cheers,
Veggie