Search: fermentation cellar 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 %.

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.

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 gas chromatography headspace method is used to determine the higher alcohols and esters present in beer, i.e., the volatile compounds are transferred from the headspace in the sample vial into the GC system for analysis. The following substances are measured in this analysis:

Acetaldehyde

Propanol-1

Ethyl acetate

2-Methylpropanol

3-Methylbutanol

2-Methylbutanol

2-Methylpropylacetate

Butyric acid ethyl ester

3-Methylbutyl acetate

2-Methylbutyl acetate

Hexanoic acid ethyl ester

The Congress wort is heated in order to inactivate the amylolytic enzymes, and afterwards, yeast is added and the wort is allowed to completely ferment out at a minimum temperature of 20 °C in a fermentation tube (fig. 1). The difference in the extract before and after fermentation is measured in order to calculate the limit of attenuation.