TL;DR: The Thermodynamics of Survival (Direct Answer) When the grid fails, cooking is no longer a convenience—it is a critical survival function for **water pasteurization**, **pathogen elimination**, and **metabolic maintenance**. The most effective blackout cooking strategy involves a "Tri-Fuel" approach: **Butane** for immediate indoor use, **Propane** for high-output medium-term needs, and **Rocket Stoves (Bio-mass)** for indefinite long-term survival. Always prioritize *