Spraying milk in an electric field removes water without heating it

Barcelona researchers used electrospray at room temperature to raise milk solids from 12.3% to 36.8%, an early proof of concept for heat-free dehydration.

Researchers at the Institute of Microelectronics of Barcelona (IMB-CNM-CSIC) and CIRTTA at the Autonomous University of Barcelona have tested a way to take water out of milk without heating it. It is the first time electrospray has been studied for dehydrating milk. The work was published in Innovative Food Science & Emerging Technologies in 2026 under the title 'Proof of concept of electrospraying skimmed milk'. The team is Bernat Perez Playà, Anna Zamora, Manuel Castillo and Llibertat Abad.

Electrospray applies a strong electric field that overcomes the liquid's surface tension and breaks it into millions of microdroplets, which lets water evaporate more readily. The run was at 20°C (68°F), using reconstituted skim milk, 29 kV and a 10 cm gap between tip and collector. At a flow of 0.2 mL/min the solids barely changed. At 0.01 mL/min, milk starting at 12.3% solids reached 36.8%, and its water content fell by nearly half. Gel electrophoresis suggested the caseins and whey proteins were not altered. The method is being patented.

This matters because conventional powdered milk relies on high heat and a lot of energy, and heat can alter whey proteins, enzymes and vitamins. If a room-temperature method can ever remove water at scale, milk could become cheaper to preserve and keep more of its nutritional quality.

The caveats are large. The team did not obtain fully dry powder under the tested conditions, and the process needs optimizing. Processing capacity, energy efficiency and scalability have not been demonstrated, and only reconstituted skim milk was tested. The authors call it a first step. Next steps include tuning flow rate, voltage and droplet travel distance, testing multi-emitter setups, and assessing energy use and microbiological stability.

Source: Phys.org