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How Malt Choices Affect Beer’s Shelf Life

In the battle against staling, understanding your malt’s free amino nitrogen content is a tactic worth deploying.

Don Tse Nov 20, 2023 - 11 min read

How Malt Choices Affect Beer’s Shelf Life Primary Image

Photo: Matt Graves/

There are many approaches to helping packaged beer taste better for longer, but here is one that more brewers should try: Get to know your malt’s free amino nitrogen (FAN) content.

“There is accepted research that high residual free amino nitrogen in finished beer results in the creation of staling aldehydes,” says Joe Hertrich, who—as the retired group director of raw materials for Anheuser-Busch—knows a thing or two about how ingredients can affect shelf life.

Free amino nitrogen, or FAN, is all the individual amino acids, short peptides, and ammonium ions that are produced when barley is germinated during the malting process. When brewers check the FAN on their malt specs, it’s typically to ensure consistency and a healthy fermentation—FAN is good for yeast growth.

However, if there is too much FAN in wort, there can be residual FAN in the finished beer. That residual FAN reacts with sugars in the beer, undergoing Strecker degradation and Maillard reactions, to create off-flavors and change the beer’s color—in short, it promotes staling.

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Don Tse is an internationally recognized beer writer and beer judge, working from his home base in the middle of North America’s barley belt.