Yujuan Wang (1); (1) North Dakota State University, Fargo, ND, U.S.A.
Malt and Grains
Poster
While rye has been used by the baking and distilling industries for
centuries, its use in brewing has traditionally been limited. However,
rye has recently become more popular as its addition can contribute
spicy or pumpernickel characteristics to beer flavor. The malting of rye
and use of rye malts presents several challenges to maltsters and
brewers. These include the lack of a hull, dense packing in steep,
extreme shrinkage in the kiln and a high content of water-soluble
arabinoxylans. There is empirical evidence that rye genotypes differ in
malting and brewing performance and flavor, but there is little
published information on the malting of rye or the malt quality
attributes of rye genotypes. The main objective of the current work was
to evaluate laboratory micromalting conditions that could be used in
quality screening. Key objectives were achieving high extract, with
minimal malt loss and lower wort viscosity/arabinoxylan content. The
experiment was conducted using a factorial design with rye sample (n = 2), kernel size fraction (n = 2:5/64 in. and ≥ 6/64 in.), steep-out moisture (n = 3:40, 45, and 48%) and germination time as variables (n
= 4: 3, 4, 5, and 6 days). Malts were mashed according to the Congress
method, but worts were centrifuged prior to filtration. Wort
arabinoxylan and phenolic acid content were determined in addition to
standard malt quality parameters. Data were analyzed using analysis of
variance. Sample was found to impact all parameters, with the exception
of FAN and arabinoxylan. Steep-out moisture did not influence extract or
arabinoxylan level, but increasing moisture was found to increase malt
loss and decrease viscosity. Germination time increased extract values
only up to 4 days, but longer times contributed to lower viscosity and
greater malt loss. Significant interactions between some parameters
confounded the interpretation of data, but in general, high extract and
lower viscosity were achieved by malting for at least 4 days at high
moisture. Several commercial maltsters, however, have indicated that the
handling of germinating rye at high moisture levels is problematic. As
such we recommend 6 days of germination at 45% moisture for future
evaluation of rye cultivars.
Yujuan Wang is an graduate student in cereal science from North
Dakota State University (Fargo, ND). Currently, she is performing
research in the area of malting and brewing technology. In 2015, Yujuan
was awarded the Rahr Malting Scholarship from the Plant Sciences
Department. That same year, she received a Statistic Certificate in
applied statistics, and she will receive a Graduate Certificate in food
protection in 2016.
