Specific surface area of soils with different clay mineralogy can be estimated from a single hygroscopic water content

•Traditional methods for soil specific surface area (SSA) are costly and laborious.•We propose models to estimate SSA from a single hygroscopic water content (wh)•Separate SSA models are developed for soil samples grouped by clay mineralogy.•Considering soil clay mineralogy in SSA models significantly improved performance.•Models based on wh were superior to models based on texture, carbon or CEC.