Energy savings in the brewhouse
Since the energy crisis in the 1970’s there was a steady increase in costs for primary energy. And nowadays everybody knows that these costs have to be reduced in the production process to come to economic products, which the consumer is able to afford. Further, the spoilage of primary energy leads to higher emission rates, which are also due to higher costs and pollution. Therefore the lowering of energy consumption must be seen as a very important factor during the whole process of production. In a brewery the brewhouse is the most energy consuming part – with mashing, heating and boiling of the wort. But it is not only the thermal energy, electric energy has to be considered too. For example, German breweries did have lowered the specific fuel heat consumption by around 40 % from 1980 to 1997. The electric energy consumption kept nearly the same in this time. But this can be
explained by the fact that the thermal energy saving potential in the brewhouse is much higher than the electric energy saving potential. To give some values, German breweries in the range of 300.000 hl to 500.000 hl of sales beer (SB) a year have a whole specific electric energy consumption of 7 – 12 kWh/hl SB and a whole specific thermal energy consumption of 90 – 150 MJ (≡ 25 – 42kWh)/hl SB. From this very high value of thermal energy the brewhouse can take part in up to 65 %, so that you come to a very high energy saving potential (11, 21).
Evaluation and utilization of spent grains
Spent grains are produced by the extraction of malt. By the extraction of malt the
soluble parts are dissolved in water, for example starch and Sow molecular sugars.
The non-soluble parts are the spent grains The brewery spent grains {BSG} are the
dominating by-product in the brewery, besides hat trub, malt dust, etc. in beer
production, about 18 - 20 kg of wet grains are produced per hl of saleable product
Sterile Filtration [comparison of different system, sheet filter, MMS, membrane filtration]
Since Enzinger introduced the filtration in 1878 many new originations
came up. [8] Through the last years the Public Relation pushes the sterile
filtration instead of thermal treatments. Trendsetters were Japan and
North America.
Filter aids Kieselguhr, Perlite, Cellulose etc.
Filtration belongs to the oldest technical treatment. It is just a separation of solid and liquid substances in a suspension and is the last process of the beer production. The yeast, protein and carbohydrate particles, which must be removed from beer to achieve the necessary degree of clarity, are of small size and are compressible. Any attempt to remove this material using a single filter medium, for example a filter sheet, would result in a rapid blockage of the filter and make this method impracticable. The high resistance to flow offered by the accumulation of material on the filter means that it is described as having a low 'Permeability'. These problems may be overcome by injecting a suitable material into the beer stream, referred to as the 'Filter-Aid'. This forms, together with the yeast and other suspended solids, an almost incompressible mass on the filter medium and referred to as the 'Filter-Cake'. This is capable of maintaining the flow of beer and is described as having a much higher permeability. Filter-aid added into the flow of beer this manner is referred to as 'Body-Feed'. But at first filter aids (very coarse ones) have to form an intermediate layer bridging the gaps in the sieves, leaves or cartridges. This so called first precoat layer acts as a support for the subsequent finer precoat or second precoat layer and later on the body feed.
