Search: monitoring brewhouse yield

Since determination of the hot wort yield can be problematic and the cold wort yield as described above does not represent a measure of the total extract obtained from the grain bill, an attempt has been made to record all of the extract recovered, with the exception of that remaining in the spent grain. This value is then compared to the laboratory yield. The result is expressed as the total yield (overall brewhouse yield) (OBY_CW) in %.

Instead of brewhouse yield, quite often the cold wort yield is calculated. Cold wort yield is particularly recommended for wort produced using adjuncts. Extract yield is understood as the amount of extract in a batch of wort relative to the amount of extract in the raw materials used to produce the wort.

The fermentation cellar yield is calculated using the value determined for the amount of extract contained in a batch of wort relative to the amount of extract present in the raw materials used to produce the wort.

The brewhouse yield/hot wort yield represents the extract present in one batch of wort relative to the raw materials used to produce the wort. The malt, any supplements added to the mash, and brewhouse operations determine brewhouse yield.

An assessment of brewhouse operations and processes is possible through comparison with the laboratory yield, prepared using the same malt and supplements in the mash. However, the brewhouse yield does not allow a distinction to be made regarding where extract losses occur in the brewhouse, i.e., whether they stem from the mashing or lautering process and in which proportions. For this, a spent grain analysis is required.

The hot break material (trub) and any hop particles which may be present in the wort, must first be removed. After the wort has been cooled to 2 °C, it is filtered through a glass fiber filter. The residue remaining on the filter is dried and then weighed.

Cold break material or cold trub refers to all material that settles out in the process of chilling wort after separation of the hot trub or hot break material. Cold trub can be filtered out of the wort and primarily consists of proteins (48–57 %), tannins (11–26 %) and carbohydrates (20–36 %). The amount of cold break material in wort depends on the quality and composition of the raw materials, brewhouse equipment and wort handling. In academic and professional circles, opinions regarding the significance of cold break material for downstream processes and for the quality of the finished beer are strongly divided [1, 2, 5]. Under certain circumstances, the quantity of cold break material in wort may exceed 250 mg/l, especially where accelerated fermentation is practiced. Ultimately, this can detract from the flavor of the finished beer [3]. Breweries, where removal of the cold break material has been practiced successfully, determine the quantity of cold break in their pitching wort at regular intervals, in order to evaluate the efficacy of their separation equipment.

The extract yield in the brewhouse is highly dependent on optimal milling of the malt or other grain. The composition of the brewery grist should therefore be monitored on a regular basis.

The sieve analysis is performed on a sample of brewery grist of a known weight with a shaking device containing a set of sieves (according to DIN ISO 3310-1 specifications or a Pfungstädter plansifter sieving device).