Analytical
Specification of Malt
Table of Contents
Discussion points on Malt specification
Typical Ranges of Values for Malt
Specifications
Analytical Techniques for
Malt
Extract from Adjuncts
Discussion
Points on Malt Specification
General Considerations
Malt should be relatively well-modified with even modification
and uniform grain size.
Malt analytical values depend on barley variety, malting conditions
including use of additives, kilning conditions and equilibration
of malt (i.e. period after kilning).
Laboratory analysis is used to establish malt quality and other
physical and chemical properties of malt.
Care should be taken to ensure that the analytical values specified
match the brewing conditions to be used such as the use of cereal
or copper adjuncts and the required nitrogen content of the wort.
Range of Values
A wide range of values of total nitrogen may be used and will lead
to a considerable variation of extract values (see table below).
Particular specifications will depend on the amount and kind of
adjuncts employed.
Other quality criteria should ideally fall within a narrow range
(see table below).
Operational Protocols
Barley variety is agreed with the supplier but is normally chosen
from the Institute of Brewing recommended list (see Appendix 1).
Use of a single variety is preferable; mixed varieties, when used,
must be compatible in malting character and grain size.
Malting should produce a friable and consistently modified product
for which four to five days germination is a good guide line. The
use of gibberellic acid, bromate or sulphuring is agreed with the
supplier.
The period between kilning and use is agreed with the supplier
but is usually 3 weeks minimum.
Malt should be inspected visually and by hand on arrival at the
brewery to check the extent and uniformity of modification (see
also Appendix 1, for use of the Friabilimeter).
Measurement Protocols
Malt is sampled using the Institute of Brewing Recommended Method
2.1. The analytical parameters which should be measured are listed
in Table 4.
Malt should be checked visually and by hand on its arrival at the
brewery.
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Typical
Ranges of Values for Malt Specifications
Characteristic
|
Range |
Tolerance |
Hot Water Extract (° per kg dry basis)
|
Min 302 (High TN Malt, ca 175 mgs/ltr) to 312 (Low TN Malt
ca 140 mgs/ltr) |
-4 |
Moisture (%)
|
2·7 - 3·3 |
+0·2 |
Colour (° EBC)
|
4 - 6 |
±1 |
Total Nitrogen, TN (% dry basis)
|
1·45 - 1·75 |
+ 0·03 (Low TN) + 0·05 (High TN) |
Soluble Nitrogen Ratio
|
38 - 40 |
±2 |
Free Amino Nitrogen (mgs/ltr @ 1040 gravity)
|
140 - 175* |
±10 (Low TN) to ±15 (High TN) |
Screenings, < 2·2 mm, %
|
1·5 - 2·0 |
+0·5 |
Corns > 2·5 mm, %
|
93 - 95 dependent upon variety and season |
-3 |
Ungerminated grains, %
|
Target 0, dependent upon season |
+2 |
Cold Water Extract, %
|
18 - 19 |
±1·5 |
Diastatic Power (° IoB)
|
35 (Low TN) to 55 (High TN) |
±7 (Low TN) to ±12 (High TN) |
Precise specifications, which should be balanced, will be agreed
between supplier and customer. It is important that analyses are
consistent between batches.
* As measured in laboratory worts which, because of factors such
as mash thickness, contain less FAN than do the brewery worts. These
values are consistent with a FAN content of 160 - 190 mgs/ltr in
the brewery wort.
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Analytical
Techniques for Malt
| Parameter |
Analytical Method |
Hot Water Extract, HW
|
IoB Recommended Method 2.3 |
Moisture
|
IoB Recommended Method 2.2 |
Colour
|
IoB Recommended Method 2.4 |
Total Nitrogen, TN
|
IoB Recommended Method 2.8 |
Soluble Nitrogen Ratio
|
IoB Recommended Method 2.9 |
Cold Water Extract, CWE
|
IoB Recommended Method 2.5 |
| Diastatic Power, DP |
IoB Recommended Method 2.6 |
Free Amino Nitrogen, FAN
|
IoB Recommended Method 8.3 (see note1) |
Screenings and Corn Size
|
Analytica - EBC method 2.7 |
Husk Character
|
Visual Inspection |
Ungerminated grains
|
Visual Inspection |
Molds
|
Visual Inspection (see note 2) |
Filtration Volume
|
See Appendix 5 |
Notes
1 Measured on laboratory wort produced by the IoB Recommended Method
2.3
2 Check taste and smell in case of contamination by moulds
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