This article argues that in the early modern period, epistemic genres were transformed to suit new purposes. Modelled on the experimental essay form used by proponents of the New Sciences, the Dutch polymath and painter Simon Eikelenberg (1663-1738) wrote down ervarenissen to document how painting materials such as varnishes were prepared. Recipes have been identified as the ubiquitous vehicles for written know-how in the early modern period, yet authors continuously searched for new ways to unpack the ineffable dimensions of know-how in text. This article explores the ervarenissen as an alternative communicative strategy. Eikelenberg appropriated the experimental essay to create expressive instructions. He emphasized the specificity and idiosyncrasy of an act of making, tried to establish a sympathetic relationship with his readers, and showed how vulnerability, failure and improvisation belong to the workshop.