Changes

The temperature at which beer is stored has also has a major impact on how beer ages. The effect that temperature has on a given reaction depends on the type of reaction; not all reactions are increased at the same rate. For example, it has been reported that beer stored at 25°C tends to develop more caramel flavor, while the same beer stored at 30°C develops more cardboard flavor <ref name="Vanderhaegen_2006" />. Bamforth and Lentini proposed a simplified version of the Arrhenius model known as [https://web.calpoly.edu/~bio/EPL/pdfs/SampleLectureBIO162.pdf Q₁₀] to generalize the rate of chemical reactions in beer based on temperature. Q₁₀ is a measure of the temperature sensitivity of chemical and enzymatic reactions due to an increase in temperature by 10°C. The equation is expressed as a ratio: Q₁₀ = Reaction Time + 10°C / Reaction Time. Bamforth recommends that for beer, Q₁₀ will be 2 or 3 (most chemical reactions fall in this range). For example, assuming a Q₁₀ of 3, storing beer at 30°C for 2 weeks is equivalent to 6 weeks at 20°C, 18 weeks at 10°C, and 54 weeks at 1°C. Assuming a Q₁₀ of 2, storing beer at 30°C for 2 weeks is equivalent to 4 weeks at 20°C, 8 weeks at 10°C, and 16 weeks at 1°C <ref>[https://www.sciencedirect.com/science/article/pii/B9780126692013000038 Charles Bamforth and Aldo Lentini. Beer: A Quality Perspective. 2009. Pgs 85-109.]</ref><ref name="Barnette_2018_Masters" /><ref>[https://web.calpoly.edu/~bio/EPL/pdfs/SampleLectureBIO162.pdf Temperature Regulation PowerPoint. Cal Poly. Environmental Proteomics Laboratory.]</ref>. Barnette's Masters thesis found that warmer temperatures had a greater negative impact on beer hop flavor and aroma than high levels of dissolved oxygen over a two week storage period in dry hopped beers <ref name="Barnette_2018_Masters" />.