DETERMINATION OF MOISTURE, TOTAL AVAILABLE EXTRACT AND SOLUBLE EXTRACT IN SPENT GRAINS

• Published in: Journal of the Institute of Brewing Vol. 103; no. 6; pp. 355 - 357
• Main Author: Castane, F X
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-11-1997; Institute of Brewing
• Subjects: Analytical method; Beers; Biological and medical sciences; collaborative trial; Fermented food industries; Food industries; Fundamental and applied biological sciences. Psychology; moisture; precision; soluble extract; spent grains; total available extract; Draff; Performance evaluation; Malt extract; Repeatability; Analysis method; Reproducibility; Multicenter study; Water content
• DOI: 10.1002/j.2050-0416.1997.tb00963.x
• EISSN: 2050-0416
• ISSN: 0046-9750

The methods for the determination of moisture4, total available3,4 and soluble extracts4 in spent grains have been collaboratively tested by members of the Analysis Committee of the European Brewery Convention to obtain repeatability (r95) and reproducibility (R95) values.
Repeatability and reproducibility values of 0.1 and 0.67 respectively were obtained for spent grain moisture's ranging between 4 and 8% m/m in pre‐dried and pro‐milled samples. In a pro‐dried and unmilled sample containing 3.4% m/m moisture the values obtained were 0.3 and 1.5 respectively.
For total available extract (MEBAK) these values were 0.5 and (2.2+0.045 m) respectively, with total available extract ranging from 9 to 42% m/m dry matter, where m refers to the actual value. The values for the pre‐dried and unmilled sample containing an extract of 41.2% m/m were 0.5 and 4.6 respectively.
The precision values for soluble extract were dependent on the extract level of the sample over the range 6 to 40% m/m dry matter. A repeatability value of 0.13+0.007 m and a reproducibility value of 0.2+0.06 m were obtained over this range. Values for the same pre‐dried and unmilled sample with a soluble extract of 38.7% m/m were 1.3 and 3.8% m/m respectively.