A malt Certificate of Analysis, commonly called a COA, gives brewers a snapshot of how a particular lot of malt performed during laboratory testing.
At first glance, it can be a lot of numbers. Extract, protein, beta-glucan, diastatic power, FAN, friability, viscosity and sieve analysis all describe different characteristics of the malt.
You do not need to be a malt scientist to understand them. Here is what the most common malt specifications mean and why they matter in the brewhouse.
Moisture Content
Moisture content measures the amount of water remaining in the finished malt.
Moisture matters for both storage stability and extract. Because water adds weight without contributing fermentable material, higher moisture effectively means less dry malt material in every kilogram or pound purchased.
Proper moisture control also helps malt remain stable during storage.
Fine Grind Extract
Fine grind extract measures the amount of soluble material that can be extracted from finely ground malt under standardized laboratory conditions.
Think of it as an indication of the malt’s potential yield under near-ideal test conditions.
Higher extract generally means more material is potentially available to produce wort, but laboratory extract should not be confused with actual brewhouse efficiency.
Coarse Grind Extract
Coarse grind extract measures extract using a coarser grind that more closely resembles practical brewery milling.
The result is normally somewhat lower than fine grind extract because the enzymes have less access to the material inside larger malt particles.
Looking at fine and coarse extract together tells us more than either number alone.
Fine/Coarse Grind Difference
The fine/coarse grind difference is simply the difference between the two extract results.
A small difference generally indicates that the malt is well modified and its extract is readily accessible.
A larger difference can indicate that more potential extract remains locked within the kernel when the malt is more coarsely milled.
Color
Malt color tells you how much color the malt can contribute to wort and, ultimately, beer.
Your COA may report color using SRM or another recognized color measurement system.
Light base malts such as Pilsner and Pale malts have low color values, while increasingly kilned and roasted malts become progressively darker.
Color also provides some indication of the malt’s kilning intensity, although it should not be used as a direct measurement of flavor.
Beta-Glucan
Beta-glucans are structural components found in barley cell walls.
During malting, these structures are broken down as the barley kernel modifies. Malt with elevated beta-glucan can produce more viscous wort and may contribute to slower lautering or filtration.
Beta-glucan is therefore useful when assessing malt modification and potential processing performance.
Total Protein
Total protein is one of the most important numbers on a malt COA.
Protein influences several other malt characteristics, including extract potential, enzyme activity and the nitrogen compounds available to yeast.
Very high protein can mean less starch and therefore lower potential extract. But lower is not automatically better. Brewers still need adequate enzyme activity and yeast nutrition.
The goal is balance.
Soluble Protein
Soluble protein measures the portion of malt protein that has been broken down and made soluble during malting.
This gives brewers another indication of how protein has been modified during germination.
Rather than looking at soluble protein alone, it is often considered alongside total protein through the Kolbach Index.
Kolbach Index
The Kolbach Index, sometimes called the soluble-to-total protein ratio, compares soluble protein with total malt protein.
It provides an indication of protein modification during malting.
A higher number generally indicates greater protein modification, while a lower number indicates less. The appropriate level depends on the malt and its intended application, so it should not be treated as a simple higher-is-better specification.
Diastatic Power
Diastatic power, or DP, measures the overall starch-converting enzyme activity of the malt.
During mashing, malt enzymes break starch into smaller sugars. Higher diastatic power means the malt has greater enzymatic capacity to perform this conversion.
This becomes particularly important when brewing with adjuncts such as corn or rice that contribute starch but little enzymatic power of their own.
For straightforward all-malt brewing, extremely high DP is not necessarily an advantage. The malt simply needs sufficient enzymatic strength for the grain bill and brewing process.
Alpha-Amylase Activity
While diastatic power measures overall enzymatic strength, alpha-amylase activity measures one important enzyme more specifically.
Alpha-amylase helps break large starch molecules into smaller carbohydrates during mashing, making the starch more accessible for further conversion.
This specification can be particularly useful when evaluating highly enzymatic base malts or malt intended for demanding mash conditions.
pH
Malt pH provides an indication of acidity under the laboratory’s standardized test conditions.
Mash pH has an important influence on enzyme activity and overall brewing performance, but the pH listed on a malt COA does not tell you exactly what your brewery’s mash pH will be.
Your water chemistry, grain bill, brewing salts, acids and process all influence the final mash pH.
Viscosity
Viscosity measures the resistance of laboratory wort to flow.
For a brewer, unusually high wort viscosity can be associated with processing challenges such as slower lautering and filtration.
Viscosity is influenced by malt modification and compounds such as beta-glucans, which is why these specifications are useful to consider together.
Free Amino Nitrogen
Free Amino Nitrogen, or FAN, measures small nitrogen-containing compounds available in wort, many of which can be used by yeast during fermentation.
Yeast needs nitrogen for healthy growth and fermentation.
The appropriate FAN level depends on factors such as wort gravity, yeast strain and grain bill. More FAN is not automatically better, just as lower protein is not automatically better.
FAN should be considered alongside total protein, soluble protein and the overall brewing application.
Sieve Analysis
The final section you may see on a malt COA is sieve analysis.
Malt is passed through screens with specific opening sizes to measure kernel size distribution. The percentage retained on each screen tells you how much of the malt consists of larger or smaller kernels.
Why does that matter?
Kernel uniformity affects milling.
A lot containing mostly plump, similarly sized kernels can be easier to mill consistently. A wide range of kernel sizes can make mill settings more challenging because a gap that properly crushes large kernels may not crush smaller kernels to the same degree.
Sieve analysis is therefore useful for understanding the physical consistency and plumpness of a malt lot.
Don’t Judge Malt by One Number
This is the most important part of understanding a malt COA.
There is no single specification that determines whether a malt is good.
Extract tells you about potential yield.
Protein, soluble protein and Kolbach Index tell you about the malt’s nitrogen content and modification.
Diastatic power and alpha-amylase tell you about enzymatic strength.
FAN helps indicate available yeast nutrition.
Beta-glucan and viscosity can provide insight into modification and processing performance.
Sieve analysis tells you about kernel size and uniformity.
And all of those numbers interact.
A malt with the highest extract or diastatic power isn’t automatically the best malt for your brewery. What matters is finding a malt with the right combination of characteristics for your equipment, recipes and brewing process.
Understanding Your Malt
A Certificate of Analysis gives brewers something valuable: data about the actual malt they are purchasing.
Learning to read that data makes it easier to compare malt, diagnose changes in brewhouse performance and maintain greater consistency from batch to batch.
At Grist Malt Company, we believe brewers should know what they’re brewing with. That’s why malt specifications and analytical data are an important part of understanding the quality and performance behind every malt.
