Herein, we introduced CW samples directly into the electrospray ionization (ESI) source, without prior separation, and linked this to the FT-ICR MS to characterise in situ chemical compounds produced during natural CW ageing (from 0 to 15 days) at room temperature (23 C). The ESI-FT-ICR MS data were obtained and compared with conventional methodologies (pH, total titratable acidity (TA), total soluble solids (TSS), microbial analyses, and ultraviolet–visible (UV–vis) spectroscopies).