A device is described to encapsulate solid flavoring substances, particularly tea or coffee, added to a liquid, particularly water, with a wing-shaped rotary slider supported rotational about a rotary axis between an initial position and an end position, which in its end position limits a space accepting the solid flavoring substances, with the device being embodied for the installation in a container with its top showing an opening to fill in or discharge the liquid, which can be closed by a lid, which for closing and opening the container opening is subjected to a rotary motion, characterized in that the rotary slider comprises at least one engagement means by which the rotary slider can be made to engage the lid at least during the rotary motion in order to close the container opening and can be rotated into its end position.