What You Need to Know
Lard is rich in saturated fatty acids (~40 %) with a melting point around 41 °C, allowing it to stay solid at refrigeration temperatures. During rendering, water is expelled and triglycerides are heated, forming a stable fat that can encapsulate meat. The solidified fat blocks moisture and oxygen, while the low water activity suppresses aerobic microbes.
The Science
Primary Reaction
rendering of lard (dehydration and melting of triglycerides) and submersion of meat in fat creates an anaerobic environment