In the case of an apparatus of 5 hectolitres (110 gallons) or double that capacity, the pitching may be accomplished by means of flasks holding from 4 to 9 litres (from 7 to 10 or 11 pints), (Fig. 79), or copper cans, tinned inside, holding from 10 to 15 litres (2-1/4 to 3-1/4 gallons), and provided at the upper conical end with glass tubes (Fig. 78). The vessel must be half or two-thirds filled with wort. For this purpose it will be well always to employ wort that has been preserved in bottles by Appert’s process. We must use a stopper provided with tubes, as represented in Fig. 79: _a b_ is a glass stopper which closes the india-rubber tube _b c_; _m n p_ is a fine glass tube, or, better still, made of copper. The tap R being closed, a long india-rubber tube is attached to the extremity of the curved tube, and the flask is completely immersed in a hot-water bath; the india-rubber tube projects from the bath and keeps the interior of the vessel in communication with the external atmosphere. If the tube _m n p_ is of copper, we may avail ourselves of its flexibility and bend it upwards, so as to place its open extremity outside the bath. The water in the bath is then gradually raised to a temperature of 100° C. (212° F.), at which it is kept for a quarter or half an hour. In the case of copper cans, it is more convenient to place them over a gas-heater. They may be treated in the same manner as the flasks with curved necks. Vessels prepared in this manner may remain in a laboratory, or in any part of a brewery, for an indefinite time, without the wort in them undergoing the least change. It gradually darkens in colour through a direct oxidation of a purely chemical nature, but no tendency to disease will manifest itself.