Wort aeration

Further experimental and theoretical investigations are being done to study in greater detail the possible influence of other key process parameters, pitching rate, pressure, wort aeration, on the fermentation process and the final beer quality. 

In some cases it can replace the need for wort aeration at pitching ... 

Several continuous processing methods provide accelerated fermentation. They make use of thermophilic yeasts, higher fermentation temperatures and more intensive wort aeration. 

Infection of the wort damages beer quality, and a major sonrce of contamination is improperly filtered aeration of the wort. Aeration requires a clean, well-filtered sterile air source for successful beer production. Hydrophobic (non-wettable) membrane filter cartridges are ideal for sterile air and gas filtration. 

The brewer next prepares the wort, the nutrient medium required for fermentation by yeast cells. The malt is mixed with water and then mashed or crushed. This allows the enzymes formed in the malting process to act on the cereal polysaccharides to form maltose, glucose, and other simple sugars, which are soluble in the aqueous medium. The remaining cell matter is then separated, and the liquid wort is boiled with hops to give flavor. The wort is cooled and then aerated. 

Add extract to IVz gallons of water and bring to a boil. Add Willamette hops, Burton water salts, and Irish moss. Boil for 25 minutes and add V2 ounce of Cascade hops. Boil for 4 minutes and add remaining Vz ounce of Cascade hops. Turn off heat 1 minute later. Cool brew pot in cold water quickly and strain into the primary fermenter filled with 3 A gallons of cold water. Aerate the wort thoroughly and pitch the yeast when cool enough. Rack to carboy after 9 days. Bottle with % cup corn sugar after 7 days in secondary fermenter. 

To the filtered wort in the fermentator is added, from a generator, a pure culture of yeast. The amount of this stock yeast added is usually about 2.3% of the grain used. The concentration of the wort may be 10%. to 11% Balling. The temperature in the fermentor at the start of fermentation is about 22° C. and during fermentation rises to 30° C. at which temperature it is held. Higher temperatures have been used but the yield of yeast is reduced. Aeration by means... 

Cells for Increasing Fermenter Efficiencies. The tower fermenter system used is described in Figure 3. Wort was used as the ethanol source, and an inociilum of an aggregating strain of Acetobacter species was prepared and added to the tower fermenter (2 litres capacity). When the level of acetic acid in the fermenter had reached about 3% w/v, the medium delivery pump was started and the flow rate adjusted to a level that gave almost complete conversion of the ethanol available into acetic acid. Undue haste in increasing the flow rate and also serious decrease or stoppage of the air flow caused the expected fall in conversion efficiency. Adjustment of the flow and aeration rate showed that a maximum V. E. of 0.82 could be attained (see Table I). 

Let us now see how yeast acts in an industrial way in a brewery wort Here the conditions differ from those of the laboratory, in particular, aeration is insufifident. It results from this that the yeast does not absorb all the assimilable nitrogen contained in the wort, but only from 20 to 36 per cart ... 

Wort freed from spent hop material and trub is cooled in order that it can be pitched with yeast. In very old breweries, the wort is cooled in shallow open vessels, using only air cooling. These open coolers or coolships had three functions cooling, aeration of the wort and separation of cold trub. 

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