alcoholic extracts of particulate solids for food or drink , and particularly of coffee grounds , are prepared in a squeezable plastics container which has a fabric filter disc across its outlet to trap the soaked grounds when the liquor extract is dispensed . a pull - off seal or cap is provided to close the container until needed . in use , liquid can be sucked back into the container by squeezing and releasing it , and used to wash a further extract from the solids .