4 min
ppl In professional brewing practice, raw material quality is assessed not "by eye", but on the basis of laboratory data. Each bag of malt is accompanied by a specification or a certificate of quality and safety for the malt, which may list dozens of parameters. For a novice technologist, these tables may appear complex. However, in practice, most decisions are made on the basis of several key indicators.
Let us examine how to read a malt laboratory analysis and use it when selecting raw materials and developing recipes.
Let us examine how to read a malt laboratory analysis and use it when selecting raw materials and developing recipes.
What is a certificate of quality and why is it needed
A certificate of quality and safety (CoA) is a document confirming the actual characteristics of a specific batch of malt.
It differs from a general specification in that it reflects the real laboratory values for that particular batch, rather than averaged ranges.
The certificate of quality is used for:
- monitoring raw material consistency;
- selecting mashing regimes;
- calculating brew house efficiency;
- preventing process deviations;
- standardising product flavour.
Key parameters that you need to be able to read
1. Extract yield
One of the key parameters. It shows how much soluble substances can be obtained from malt under standard mashing conditions.
Typical range for base malts:
- 81–83 % (on dry basis)
What is important to understand:
- high value = greater potential wort yield;
- low value = possible efficiency losses;
- important for production cost calculations.
2. Moisture content
Shows the water content in the malt.
Typical standard for barley malts: up to 5.0 %
Why it matters:
- affects shelf life;
- affects the accuracy of grist calculation (water weight in the bag reduces the actual mass of extract);
- elevated moisture = microbiological risk.
3. Total protein
Protein affects several aspects at once:
- foam formation;
- haze;
- yeast nutrition;
- filtration.
Optimum for base malt: 9.5–11.5 %
Excessively high protein can lead to:
- haze;
- filtration problems;
- flavour instability during storage.
4. Kolbach index
Reflects the degree of protein dissolution during malting and serves for selecting an appropriate mashing regime. It is recommended to analyse this indicator in conjunction with total protein content.
Target range for a number of base malts: 39–41 units.
- If the index is too low, enzyme activity is insufficient, which can lead to reduced extract yield, cloudy wort and difficulty in filtration.
- If the index is too high, the balance of protein components is disrupted. This accelerates yeast ageing and impairs beer flavour.
5. Diastatic power
Shows the activity of enzymes that break down starch, measured in WK (Windisch‑Kolbach) or Lintner.
Practical significance:
- determines the ability of the malt to saccharify not only itself, but also added adjuncts;
- critically important for recipes with unmalted raw materials (rice, maize, oats).
6. Wort viscosity
Standard for most malt types: ~1.50–1.60 mPa·s
Affects:
- filtration rate;
- risk of mash sticking;
- efficiency of sparging.
High viscosity is often associated with an excess of β‑glucans.
How a technologist uses specifications in practice
A novice specialist should understand: laboratory data are not theory, but a process management tool. Depending on the indicators of each malt batch, one can choose the most optimal mashing regime, which helps to maximise both the flavour qualities of the future beverage and the economic efficiency of production.
Example 1: adjusting the mash
If diastatic power is high → one can use:
- simpler mashing schemes;
- fewer protein rests.
If low → the following is required:
- longer rests;
- iodine test monitoring.
Example 2: calculating extract yield
Extract yield directly affects:
- planned wort gravity;
- litre yield per tonne;
- cost price.
Example 3: monitoring product consistency
If CoAs of different batches differ, then:
- the technologist adjusts the regime;
- the brewer checks filtration;
- a change in pH or water may be necessary.
Common mistakes of novice specialists
1. Ignoring protein
Protein is often underestimated, although it affects foam density, beer clarity and overall flavour stability.
2. Blind reliance on a single indicator
For example, some specialists look only at malt extract yield. However, a high value in that single indicator does not guarantee a good result without taking into account other variables such as enzyme availability, crush quality or malt modification.
3. Misunderstanding of ranges
It is important to remember that specifications present ranges, not exact values.
Laboratory analysis of malt is the technologist's primary tool, which makes it possible to manage beer quality at the raw material stage. Even a basic understanding of the key indicators enables one to select the right malt for the style; predict brew house efficiency; reduce process risks and stabilise product flavour. The sooner a novice specialist or home brewer learns to read certificates of quality and specifications, the faster they will begin to improve in their chosen profession or favourite hobby.
