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A tower brewery is a distinct form of brewery, identified by its external buildings being arranged in the form of a vertical tower. The purpose of a tower brewery is to allow this multi-stage flow process to continue by gravity, rather than lifting or pumping the brew liquor between stages. Once the bulk raw materials, water and barley malt, are first raised to the top of the tower, they can then mostly flow downwards without requiring further pumping. Tower breweries developed in the late Victorian period, the first examples from around 1870,〔 the majority in the 1880s. At this time steam power was available, but not electricity. Powering a single large pumping step was practical, but multiple small pumps around a building would be much less so. The buildings of a tower brewery are arranged as a tower with around six floors. There may be a single tower, but many breweries were less regular, with portions reaching varying heights. Only relatively small areas were needed for the highest floors. The highest point would be a small water tower, the next highest a prominent ventilated attic giving good airflow for coolers. == Brewing process == The brewing process comprises many stages, each taking place in their own specialised vessels. Multiple brews may be in progress simultaneously, a new brew being mashed and boiled most days, then allowed to ferment for a week in one of several sets of fermenting tuns. Brewing begins at the top of the tower. Water is pumped up to the 'cold liquor' storage tank (5th floor), liquor being the term for the water that will become beer. The quality of this water is extremely important in brewing, often controlling the location of the brewery. In many cases it is taken from a borehole and so will already have been pumped from below ground, before being raised up the tower.〔, Stage one〕 The second main ingredient in beer is barley malt. This has already been malted in a malthouse outside the brewery tower and may have been stored for some time since. The malted grains are lifted up the tower mechanically, by either a sack hoist or a continuous elevator. From here they are fed into a grist mill (4th floor) which crushes the grains to open their seed coat and allow good extraction of their contents.〔, Stage two〕 The 3rd floor is used for temporary storage before the first major brewing step. Grist is weighed and stored in the grist hopper. Liquor is heated in the hot liquor tank. Steam is used for this heating, which avoids the need for both a furnace, and its fuel, high up in the tower.〔, Stage three〕 Brewing proper begins with mashing, the steeping of a mash of the grist with the hot liquor in a mash tun on the 2nd floor to extract the maltose sugars and other starchy components of the grist. This produces a sweet, sticky liquid called wort. The process is begun early in the morning on a brewing day and takes a couple of hours. This time allows starches from the malt to convert to sugars that can be fermented. The wort is lautered or run off for brewing and then sparging, spraying the drained mash from above with more hot liquor for a couple more hours, extracts the remaining sugars.〔, Stage four〕 Wort is allowed to run down into the brew coppers or kettles on the 1st floor.〔, Stage five〕 These are heated, originally by fires beneath them. To give better temperature control, these too are now usually heated by steam. Their temperature is gradually raised to boiling point as the wort is slowly run in. Hops are now added. The precise type of hops and even the time at which they are added are crucial factors in the taste of particular beers. Once all the wort is in the copper, boiling proceeds to extract the bitter flavours from the hops for an hour or so. The spent hops are removed from the bitter liquor by decanting or 'casting' it into the hop back, a vessel on the ground floor beneath the coppers. The spent hops settle out and the liquor is strained through them.〔, Stage six〕 A non-gravity process now takes place, where the liquor is pumped back up the tower to coolers in the fourth floor attic.〔, Stage seven〕 A green or unfermented wort still at brewing temperatures would kill the yeasts used in fermentation, so must first be cooled. Cooled liquor flows down to the first floor and the fermenting tuns.〔, Stage eight〕 Yeast is added and fermentation begins. Fermentation takes around a week and a large brewery may have enough fermentation volume to contain several brews simultaneously. The large area needed often extends into a lower building alongside the brewing tower. Towards the end of this time, the yeast is removed. Beer from the fermentation vessels is run to storage on the ground floor below.〔, Stage nine〕 Here it may be cleared, filtered and stored before being racked into casks kept on a stillage.〔, Stage ten〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tower brewery」の詳細全文を読む スポンサード リンク
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