Density bridges two classical quantities (mass and volume) which are the major driving elements in economic transactions with important goods, ranging from food to fuels. At present, only  few European NMIs possess the appropriate expertise to perform liquid density measurements from the primary‑level, i.e. hydrostatic weighing apparatus, to the secondary‑level, i.e. oscillation‑type density meters, with a level of accuracy and uncertainty that meets national (e.g. to fulfil national laws) and international (e.g. to fulfil European Directives and standards) needs (i.e. 0.002 kg/m³ to 0.005 kg/m³ (first-level), 0.01 kg/m³ to 0.05 kg/m³ (second-level), 0.1 kg/m³ to 0.5 kg/m³ (second-level up to 600 bar). As proof of this, in the latest EURAMET intercomparison (EURAMET.M.D‑K2 (1019)) [12], performed with the hydrostatic weighing method, around 36 % of the results obtained by the participants were unsatisfactory results (E_n > 1) and the mean measurement uncertainty obtained was from 4 to 13–fold of the ones obtained by the pilot laboratories (i.e. from 0.002 kg/m³ to 0.006 kg/m³). Therefore, as this method is at the top of the density traceability chain, inadequate performance is very likely to jeopardise the accuracy and the precision of the liquid density traceability chain down to the second‑level measurements at NMIs and accredited calibration laboratories, and down to the third‑level used in industry and research laboratories.