Lesson 6 - Malt Quality
This lesson deals with malt quality. We explore each parameter on a malt specification sheet and identify why they are specified. We then examine how they affect beer and the brewing process.
Modification Analyses (continued)
Fine / coarse difference
The difference between the extract values of the finely and coarsely milled malt in a standard mash also give you an indication of how well modified the malt is. We covered the method used for both EBC/ASBC and IoB standard mashes earlier in the lesson.
In a well modified malt the cell walls and protein matrix are broken down to a greater extent than a in poorly modified malt, meaning its starch is more accessible. A well modified malt will therefore provide more extract than an under modified malt when milled coarsely. Therefore the smaller the difference between the finely and coarsely milled mash extracts, the better the modification. Well modified malt has a fine coarse difference of 0-0.5%, whereas results > 1.5% indicate that modification might be lower than desired.
Cold water extract (CWE)
This test determines how much extract is available from the malt without the action of the malt enzymes. As starch is broken down to some extent during modification, the amount of extract available provides a guide to the extent of modification. In the test, malt is milled and mashed at 20˚C and enzymes are inhibited by adding ammonia solution. After mashing, the wort is recovered and its density is measured. Results are expressed as a percentage of the malt’s mass.
Acceptable figures are 15-22% of the malt’s dry weight.