Freeze drying breastmilk into powder is done through a process called sublimation. Freeze drying is different than dehydrating, which uses very high heat and is relatively faster. With freeze drying, ‘low and slow’ is the name of the game to protect precious nutrients. Water inside your breastmilk is removed using low temperatures and pressure systems. Available studies have found that lyophilization (freeze-drying) preserves many vital molecules present in breast milk. This process preserves the breast milk for up to three years!