“Mashing” over, the next process is to give the malt-tea its bitter flavour, and this is done by boiling it in a huge copper with a quantity of hops. When sufficiently boiled, the hops and wort are run off from the copper into huge square vessels (technically “hop-backs”) with perforated bottoms, which act as strainers or colanders, the liquid passing through the holes, leaving the hops behind, which are subsequently pressed to get all the liquid out of them. The brewer has now a quantity of unfermented hot beer, which he must first cool by passing it among pipes containing icy cold water. Refrigerators and ice-making machines are, it need hardly be said, of the greatest assistance to the modern brewer, who without them could only brew in the cold months. Some firms have spent as much as £8,000 on their ice-making machines. The beer, which at present is a teetotal drink devoid of alcohol, having been cooled, is turned into large tubs or square boxes, and yeast is added to it. Fermentation now sets in, and by various ingenious contrivances the froth as it rises to the top is skimmed off or carried away. During this process the beer is kept at a low temperature by means of cold water-pipes which are taken through the fermenting tuns. When the fermentation has almost ceased, the beer is put into smaller vessels,[64] where a little fermentation still goes on, and the froth either works over the side or is skimmed off or, as in the “union” system at Burton, works up through pipes. Fermentation being now practically at an end, the beer goes into huge vats, from which it is drawn into casks as required. This last operation is termed “racking.” Even then the bung-holes are left open for a day or two to allow a little froth to work out. [64] There are several varieties of these vessels: Pontoons, unions, &c., the most approved being shallow trays. On these the yeast rises very quickly. The process is termed “cleansing.” The foregoing process seems, and is, of a simple character, but to {334} obtain the very best results great skill is necessary. The colour of the malt, the temperature of the water in the mash tun, the temperature during fermentation, the proper proportion of the materials, and many other matters are of the greatest importance. Some brewers, and notably Messrs. Guinness & Sons, keep their beer in vats for a considerable length of time before racking it into the casks, but the practice is gradually dying out, and huge vats such as that built some years ago by Messrs. Meux & Co. are now but little used. The racking room of a large brewery is a wonderful sight. All round the sides are huge vats—twenty or thirty, perhaps—in each of which fifteen to twenty people could dine comfortably. These giant tubs tower above thousands of barrels which line the floor, and which look like pigmies by comparison.