A container that seals in a volume of material is provided. The container may be routinely opened, closed and material may be removed or added. A removable plate and a base define a maximum volume available for material when the container is sealed. A screen may be disposed between the plate and the base. The screen may optionally be comprised within the base, adhered to the base, or removable from the base. Features for enabling manipulation of the plate and/or screen are optionally provided.

The embodiments of the present disclosure provide a stopper comprising a plug and a pierceable membrane, the plug including a cavity between a pierceable membrane and a lower opening. The pierceable membrane and the cavity can form a tortuous path that reduces interactions between the contents of the container and the ambient environment. The cavity can be bounded by a plastic insert disposed within the plug. The plastic insert can include insert walls, the lower opening, and an insert flange. The pierceable membrane can be bonded to an upper surface of the insert flange.