Variability of brewer's spent grain within a brewery

Brewer's spent grain (BSG) is the residue left after separation of the wort during the brewing process. Composition of BSG may vary with barley variety, time of harvest, characteristics of hops and other adjuncts added, and brewery technology. This paper, demostrates the variability in composition (moisture, protein, fat, ash and total phenolics) of eight lots of spent grain supplied by a brewery. Fresh samples were oven-dried (60 degreesC, 18 h) to ensure preservation. The eight lots of BSG were found to be homogeneous in protein and fat contents, with slight variations in ash and total phenolics. In order to evaluate the possible effects of oven-drying, results from oven-dried samples were compared with those from freeze-dried and frozen samples. Oven drying of BSG gave rise small decreases in protein and fat contents in comparison with the wet (frozen) sample. Oven drying was similar to freeze-drying, a less-harsh preservation method. However, oven drying is indeed the method of lowest economic cost, which make it more suitable for preserving the BSG for exploitation in different processes. (C) 2002 Elsevier Science Ltd. All rights reserved.