A container holding, and a method of storing, freeze-dried biological samples. The container includes a chamber having an upper portion and a lower portion. The chamber includes a wall, and the lower portion of the chamber is fluidly connected to the upper portion of the chamber such that, when liquid is received at the upper portion, the received liquid can pass to and accumulate in the lower portion. Further, the freeze-dried material is located in the lower portion, and the container includes a physical structure in the form of a stop protruding inwards from the wall, the physical structure being for inhibiting the freeze-dried material from moving from the lower portion of the chamber to the upper portion of the chamber.