What is NDMA and why is it tested in malt and beer?

NDMA (N-nitrosodimethylamine) is a nitrosamine that can form during the malting process. When barley is kiln dried at high temperatures, nitrogen oxides in the kiln atmosphere can react with amines naturally present in the grain. The result is trace-level NDMA formation in the finished malt.

Modern malting techniques have reduced formation significantly compared to earlier decades, but trace levels can still occur. Because NDMA is classified as a probable human carcinogen, even low concentrations are worth monitoring.

Does NDMA survive brewing?

Yes. NDMA formed during malting can persist through the brewing process into wort and finished beer. It is not removed by boiling, fermentation, or filtration. This means that if NDMA is present in the malt, it can carry through into the final product.

Monitoring both raw malt and finished beer gives a complete picture. Testing malt on intake tells you what you are starting with. Testing the finished product confirms what the consumer receives.

How is NDMA measured in malt and beer?

NDMA in brewing matrices is measured using gas chromatography with a Thermal Energy Analyser (GC-TEA). The TEA responds specifically to the nitrogen-oxide bond present in all nitrosamines, which means it distinguishes NDMA from the sugars, alcohols, and other organic compounds that make up the bulk of a beer or malt sample.

The Ellutia 200 Series GC with an 800 Series TEA achieves detection below 1 ppb for NDMA in these matrices. The method provides clean separation and stable baselines even in complex brewing samples.

How is this different from routine brewing GC work?

ABV testing, VDK analysis, and flavour profiling all use a GC with a Flame Ionisation Detector (FID). NDMA testing requires a different detector. The FID responds to organic carbon compounds broadly. It cannot selectively detect nitrosamines at trace levels in a complex matrix.

The TEA is a separate instrument from the FID. A brewery that needs both routine analysis and NDMA testing would typically run a 200 Series GC with FID for day-to-day work and a second Ellutia 200 Series GC  with 800 Series TEA for nitrosamine analysis, or use the ATNA for total nitrosamine screening.

Is this suitable for routine monitoring?

Yes. The method is stable and repeatable, making it practical for laboratories that monitor malt quality on intake or test finished products on a regular basis. It is not limited to one-off investigations.

Want to discuss NDMA testing for your brewery or maltings? Get in touch with the team.