Temperature Changes Aren't What's Skunking Your Beer

Light exposure is what causes beer to rapidly degrade. Here’s how we proved it.  

Published Jan. 9, 2023.

Have you ever bought a case of chilled beer and emptied out a section of your fridge to store it all, fearing that its flavor would quickly degrade if the cold brew warmed up and was then chilled again for serving?

I have, many times, often causing the demise of whatever produce got relegated to the kitchen counter for a day or two.

As it turns out, my worries were misguided. Yes, beer is a perishable product that stays fresh-tasting longer when it’s stored cold. But subjecting it to temperature fluctuation? No harm done. Here’s proof.

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Letting Beer Go From Cold to Warm and Back to Cold Again Doesn't Ruin It

  • TEST: We divided a case of chilled beer (in cans to avoid any issues of light exposure—more on that later) into two groups. Half went into the refrigerator as a control, while the others spent 3 hours in an 85-degree water bath, followed by an overnight chill. We repeated the “shock” process three times and tasted both batches of beer side by side. 
  • RESULTS: Both tasted fine.

Light Exposure Ruins Beer

The real culprit of off-tasting beer—often called skunked beer or lightstruck beer—is light exposure. When bitter-tasting molecules in hops are exposed to light, which often happens when beer is bottled in green or clear glass, or when it’s poured into a clear vessel for drinking, a chain reaction occurs that produces a compound called 3-methyl-2-butene-1-thiol (MBT), a component of skunk spray. It doesn’t take much MBT to make beer taste skunky: Some astute tasters have detected as little as one-billionth of a gram per 12 ounces of beer. And the reaction happens fast. Here’s proof. 

  • TEST: We prepared three samples from the same six-pack sold in dark amber bottles: one that we poured into a clear pint glass; a second kept in its dark bottle; and a third kept in its bottle but also wrapped in aluminum foil to block as much light as possible. We placed the samples on a sunny windowsill for 30 minutes and then tasted them.  
  • RESULTS: The beer in the pint glass developed pronounced off aromas and flavors; both bottled samples tasted fine.

Bottom Line: Minimize Light Exposure

The best way to keep beer tasting fresh is to buy it in cans or dark bottles. And if you’re not drinking it directly from the package, wait to pour it into a glass until just before consuming.  


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