{"id":49507,"date":"2026-09-10T09:43:40","date_gmt":"2026-09-10T13:43:40","guid":{"rendered":"https:\/\/www.thebeertimes.com\/?p=49507"},"modified":"2026-09-12T10:31:15","modified_gmt":"2026-09-12T14:31:15","slug":"the-preservative-that-could-help-curb-contamination-in-alcohol-free-beers","status":"publish","type":"post","link":"https:\/\/www.thebeertimes.com\/en\/the-preservative-that-could-help-curb-contamination-in-alcohol-free-beers\/","title":{"rendered":"The Preservative That Could Help Curb Contamination in Alcohol-Free Beers"},"content":{"rendered":"
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The finding, published in March 2026 by a team from Wageningen University & Research, responds to a specific technical problem in the industry.<\/p>\n

\"Barley<\/p>\n

Brewing beer with less than 0.5% alcohol involves stopping fermentation early or removing ethanol afterward, and in both cases more residual fermentable sugar remains in the liquid than in a conventional beer.<\/p>\n

That sugar is precisely the ideal substrate for contaminating wild yeasts<\/a>, and the diastaticus species is the most problematic because it produces the enzyme glucoamylase, capable of fermenting dextrins that normal brewing yeast does not touch.<\/p>\n\n

Why Is Alcohol-Free Beer More Vulnerable to Contamination?<\/h2>\n

A bottle of alcohol-free beer contaminated with diastaticus does not only develop strange flavors. The yeast keeps fermenting inside the already sealed container, generates additional CO\u2082, and can end up in overcarbonation or, in extreme cases, in bottles that explode at the point of sale.<\/p>\n

That is why the industry has been looking for years for preservatives that control this yeast without relying on aggressive pasteurization, which also alters the delicate sensory profile of these beers.<\/p>\n

The usual chemical preservatives, such as potassium sorbate or sodium benzoate, fulfill the function, but clash with the clean label<\/a> trend that drives much of the growth of the alcohol-free segment. Hence the interest in compounds of natural origin that the brewing industry itself already generates as a byproduct.<\/p>\n

What Are Phenolamides and Where Do They Get Them From?<\/h2>\n

Phenolamides are molecules that combine a hydroxycinnamic acid (such as ferulic acid or coumaric acid) with an amine, in this case agmatine, a polyamine that barley accumulates naturally during germination.<\/p>\n

The Wageningen team worked with hydroxycinnamoylagmatines, abbreviated HCAgm, and obtained them by two routes. One was chemoenzymatic synthesis in the laboratory.<\/p>\n

The other was direct extraction from barley rootlets, the sprout that detaches during malting and that malt houses usually discard as a low-value residue.<\/p>\n

The clean label trends and the growing popularity of alcohol-free beer have generated demand for natural compounds that prevent microbial spoilage.<\/p><\/blockquote>\n

The Result They Did Not Expect and the One That Did Work<\/h2>\n

The team’s first trial tested simple hydroxycinnamic acids, their dimers, and HCAgm in their monomeric form against diastaticus, and none of these compounds inhibited yeast growth.<\/p>\n

The result changed when they subjected the HCAgm to oxidative coupling to generate dimers.<\/p>\n

Those HCAgm dimers did inhibit Saccharomyces cerevisiae subsp. diastaticus, in a concentration range of 46 to 255 micrograms per milliliter (Van Zadelhoff et al., Journal of Agricultural and Food Chemistry, 2026, retrieved via PubMed on 09\/10\/2026).<\/p>

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The chemical reading of the finding is that neither the hydroxycinnamic acid alone nor the amidation with agmatine is sufficient separately.<\/p>\n

It is the combination of amidation and oxidative dimerization that produces a molecule with real anti-yeast activity, something the authors had not anticipated when designing the experiment with the monomeric forms as the most likely candidates.<\/p>\n

From Malt House Residue to Preservative<\/h2>\n

The fact that the active compound can be extracted from barley rootlets, a byproduct that today is sold as animal feed at a low price, opens an interesting path of valorization of brewing byproducts<\/a> for malt houses.<\/p>\n

The study, however, was done in laboratory trials with the isolated yeast, not in packaged beer or under plant conditions.<\/p>\n

It remains to be verified whether the inhibitory concentration holds in the presence of hops, residual alcohol, and other compounds of the real beer matrix, and the stability of the compound during storage of the finished product also needs to be validated.<\/p>\n

For a craft brewery, the finding today is more a signal of where research in natural preservation is heading than a tool ready to use in the plant.<\/p>\n

The industrial scale of HCAgm extraction from rootlets, if it comes, will depend on some malt house or ingredient supplier deciding to invest in the purification process.<\/p>\n

Frequently Asked Questions (FAQ)<\/h2>\n

1. What is Saccharomyces cerevisiae subsp. diastaticus and why does it affect alcohol-free beer more?<\/h3>\n

It is a contaminating wild yeast that produces the enzyme glucoamylase, capable of fermenting dextrins that standard brewing yeast leaves intact. Alcohol-free beer retains more residual fermentable sugar than a conventional beer, so it offers more available substrate for this yeast to grow inside the already packaged bottle.<\/p>\n

2. What exactly are hydroxycinnamoylagmatine dimers?<\/h3>\n

They are molecules formed by two units of HCAgm, a compound that combines a hydroxycinnamic acid with the polyamine agmatine, joined by oxidative coupling. The Wageningen study found that only this dimeric form, and not the monomers, inhibits the growth of diastaticus yeast.<\/p>\n

3. Are these preservatives already used in commercial beers?<\/h3>\n

No. The study is basic research, with laboratory trials against the isolated yeast. There is still no validation in packaged beer or storage stability evaluation, so their commercial use would depend on additional research and on some supplier investing in scaling up the extraction or synthesis.<\/p>\n

4. Why are barley rootlets an attractive source of these compounds?<\/h3>\n

Because they are a byproduct that any malt house already generates at high volume and that today is destined almost entirely to low-value animal feed. Extracting a natural preservative from there would fit the circular economy logic that several brewing byproduct valorization initiatives already pursue.<\/p>\n