Microwave heating of liquids is a very complex, non-linear three-way coupled problem, where electromagnetics, fluid dynamics and thermal energy are coupled through convective heat transfer and temperature dependent properties such as permittivity, density, viscosity, and phase change. To make things even more challenging, fluids can be represented either with Newtonian (water, alcohol) or Non-Newtonian (ketchup, resin) viscosity models. We have numerical models for different kinds of fluids and all common microwave excitation ports, including magnetron antennas and rectangular waveguides.