What is the measurement range for malt?
Important parameters, ring trials and sensitivity
The measurement of important parameters in malt is standardized by brewing organizations like the European Brewing Convention (EBC) or the American Society of Brewing Chemists (ASBC). To ensure the reliability of the measurement across different labs, there are monthly ring trials conducted by several organization like VLB, IFBM and LGC (MAPS). These trials follow the protocols described by EBC or ASBC. The ring trials supply a valuable tool to the participants, to compare the reproducibility of their method with the other participating laboratories.
For malt enzymes analysis, namely alpha amylase and diastatic power (DP), results are given per mas of "dry matter". The parameters recorded in an analysis are “corrected” to give values as though the malt were dried to 0% moisture content. This enables fair comparisons between lots which will inevitably have different moisture percentages.
There are several groups of malt to think about when discussing the measurement range for malt:
It is the brewer’s favorite malt for making beer. In a nutshell, it is barley grains that have been allowed to germinate by soaking the grain in water. The germination is later stopped by applying heat (kilning). It can also be divided in 2 groups: regular barley malt and high DP malt.
The range of measurement DP for regular barley malt is between 220 WK and 600 WK, as stated by the EBC. Diastatic power (DP) is the combined effect of both alpha and beta amylase; because beta amylase is the limiting factor in DP, it is directly correlated to its activity.
Historically, the alpha amylase measurement range has been normally between 40 DU and 70 DU.
When it comes to high DP malt, produced with a gentler kilning than in regular DP malt, the measurement range is anything above 500 WK, but it is most commonly between 650 WK and 800 WK.
The range is approx. the same for alpha amylase for high DP, sometimes reaching 80 DU, but not as far apart in comparison to DP.
Some specialty malts, like Munich malts, are produced after a more intense kilning, which reduce the DP, but at the same time contributes with a more intense color, as well as a malty and grainy characteristic to the final beer recipe. The measurement range for DP is typically between 50 and 100 WK.
Is the second most common malted grain used in brewing. Wheat is malted with a similar malting process to malting barley, with a shorter steeping time as the wheat does not contain its husk, and therefore absorbs water at a faster rate to allow for germination.
The measurement range for DP is normally between 200 and 500 WK, and it is used especially for adding foam to the final beer, or to produce Weissbier.
How sensitive is the assay with temperature?
Each enzyme has an optimal temperature at which it performs its best. For beta amylase is 63° C and for alpha amylase it is 72° C. At those temperatures though, they also degrade faster. These optimal temperatures correspond to the maximum kinetics that the enzymes can hydrolyze the starch into sugars.
We have observed that alpha and beta amylase are also active before reaching the previously mentioned temperatures. For instance, they can be active even at room temperature.
GlycoSpot performs the experiments at 35° C, because we want to be above room temperature in any factory using or producing malt worldwide. The enzyme kinetics are temperature sensitive – only 1° C in temperature difference could lead to a 5 to 10% error, and room temperature is not an accurate setpoint. Therefore, GlycoSpot has introduced a heated incubator as a standard element in our 14-day free trial package. A heated incubator provides temperature consistency in different environments, a condition that is not satisfied by the room temperature premise.
All heat boxes are calibrated to perform the same, ensuring great reproducibility chances and results through-out different locations and environments, regardless of room temperature.
Read more about Assay Accuracy in Malt