Cracking Open the Evidence: Methods Used to Test Gluten-Removed Beers

Written by Alyssa Ramuscak, Research Analyst Celiac Canada, June 24, 2026

Summer is officially here! Patios are open, vacations are booked, and many people are looking forward to enjoying a cold drink with friends and family.

For those living with celiac disease, ordering a beer often comes with an extra question: Is it gluten-free?

In Canada, beers labelled “gluten-free” are made from naturally gluten-free grains, such as sorghum, rice, millet, or corn, and have undergone rigorous testing to ensure that they are less than 20 parts per million (ppm) of gluten, a threshold for labelling a product as gluten-free.

Gluten-reduced or gluten-removed beers are different. These beers are brewed using gluten-containing grains such as barley or wheat and are treated with enzymes designed to break down the gluten proteins. However, questions remain about whether all gluten protein fragments are completely removed during this process and whether current testing methods can detect any fragments that remain.

A recent study from Germany explored just that, suggesting that some industry standard tests may not be detecting every gluten fragment present in these gluten-reduced beers.

Methods to Testing Gluten Reduced Beers

Researchers analyzed four regular beers containing gluten and 22 beers labelled as “gluten-free barley beers”* against three different methods:

G12 ELISA
R5 ELISA
A newer, more sensitive technique called nano-liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS).

ELISA, or Enzyme-Linked Immunosorbent Assay, is the standard laboratory method used to detect gluten in foods and beverages. These tests use antibodies to detect specific proteins, such as gluten protein fragments. However, not all ELISA tests look for the same gluten protein fragments. For example, the R5 ELISA, one of the most widely used gluten tests, only tests specific protein sequences (QQPFP, QQQFP, LQPFP, QLPRP), whereas G12 recognizes a different set of gluten protein sequence (QPQLPY, QPQLPF, QPQLPL, QPQQPY). Because they’re looking for different targets on proteins, they may produce different results.

On the other hand, the mass spectrometry method does not rely on antibodies. Instead, it identifies and measures molecules directly, allowing researchers to identify more gluten protein fragments.

What did the researchers find?

Among the three methods examined, the researchers found the following results:

The G12 ELISA confirmed gluten concentrations below 20ppm in all beers labelled as “gluten-free”;

The R5 ELISA detected concentrations above 20ppm in four of the “gluten-free” beers; and,

With the mass spectrometry method, 44 gluten protein fragments were identified, of which 29 were found in the “gluten-free” beers.

The most notable finding from this study was that of the 44 gluten protein fragments identified from the mass spectrometry method, seventeen of the gluten protein fragments did not contain a sequence that would be recognizable in the R5 or G12 ELISA.

What do these findings mean for people with celiac disease?

While these findings may sound concerning, there is an important limitation to keep in mind.

Although the researchers detected additional gluten protein fragments, they did not test whether these fragments actually trigger symptoms, intestinal damage, or immune responses in people with celiac disease. In other words, while the study identified these gluten protein fragments, we still do not know whether they cause clinically meaningful harm.

The researchers also noted that the concentrations of these fragments were very low and remained below the European Union’s gluten-free threshold.

Bottom Line

Industry standard testing methods such as the R5 or G12 ELISA remain advantageous for rapid, cost-effective, and high throughput screening; however, it may miss some gluten protein fragments in commercially available gluten-reduced barley beers.

Findings highlight the need for further research to determine whether additional gluten protein fragments detected by the mass spectrometry have any health implications for people with celiac disease.

With more research, it may be advisable for industry to adopt a combination of established ELISA test with mass spectrometry methods to make gluten-free foods safer for people living with celiac disease.

In the meantime, if travelling to Europe this summer, it is important to be mindful that labelling laws are different than Canada’s. In Europe, gluten-removed barley beers are legally labelled as “gluten-free” if they contain less than 20mg/kg (20ppm) of gluten. However, as the study reviewed in our blog post reveals, some standard industry tests can miss small, harmful protein fragments that remain in these barley-derived, enzyme treated beers.

As recommended by Celiac Canada, people living with celiac disease should avoid gluten-removed or gluten-reduced beers, and opt for naturally gluten-free alcoholic beverages, such as wine, ciders, distilled spirits, or gluten-free beers with sorghum, rice, millet, or corn.

Read the study here:

Tissen E, Geisslitz S, Maier B, Scherf KA. Identification fo celiac disease-active peptides in gluten-free barley beers by nanoLC-MS/MS. Applied Food Research, 2026;6:101952. https://doi.org/10.1016/j.afres.2026.101952

*Important note: in the Europe, gluten-removed barley beers are legally labelled as “gluten-free” if they contain less than 20mg/kg (20ppm) of gluten.