Drum drying is a continuous drying process in which liquid or pureed product is spread as a thin film onto a heated rotating drum and scraped off as dried flakes or powder, used mainly for purees and starch-rich materials.
In trade practice
Suppliers use drum drying for fruit and vegetable purees where the high surface temperatures involved are acceptable for the product’s flavour and colour profile. QA teams check the resulting flakes or powder for moisture content, colour, bulk density and absence of scorched particles. Drum-dried products are often compared with spray-dried equivalents in buyer specifications, as the two methods produce different particle structures and solubility characteristics. The method is generally more energy-efficient than spray drying but less suitable for heat-sensitive ingredients.
In a specification
A specification for a drum-dried ingredient should state the drying method explicitly alongside moisture, bulk density, particle size and colour parameters, as these differ from spray-dried equivalents of the same raw material.