Impact of storage conditions on the oxidative stability of beer

The impact of different storage conditions on the generation of radicals was evaluated through electronic paramagnetic resonance (EPR) detection of spin adducts based on the Fenton reaction, after an accelerated aging of beer (55 degrees C for 150 min). The different conditions applied, namely storage time and temperature, have clearly demonstrated to affect the beer oxidative stability. The greater endogenous antioxidant potential (higher lag phase values) observed for fresh beers is due to the higher levels of SO2. In contrast, the higher levels of radicals observed after 150 min of accelerated aging are related to the higher content of iron in fresh beers. Lower levels of SO2 and iron found in aged beers are therefore related to the lower endogenous antioxidant potential and the lower levels of radicals after 150 min of accelerated aging, respectively. According to our model for shelf-life prediction, the best-before date of beer can be reduced from 6 months, if stored at 20 degrees C, to as little as 9 days if it is stored at 37 degrees C.