Abstract: A lid component for use with a glass jar and band of a mason jar, and a fermentation kit comprising these components. The lid component is made of an air-impermeable material and is dimensioned and configured to be releasably attachable to the jar by the band and to seal the wide mouth opening of the glass jar in an air-tight manner. The lid component further comprises a one-way valve adapted to allow gas produced by a fermentation process occurring inside the jar to escape from the jar while, at the same time, prevent oxygen-containing air from entering the jar, when the lid component is releasably attached to the jar.