Empirical Study of Carbon Dioxide Released to the Atmosphere during Commercial Red Grape Fermentation

Carbon dioxide (CO2) is a pollutant (greenhouse gas) that is emitted during winemaking but not currently regulated by the Environmental Protection Agency. While winery CO2 emissions have been modeled, they have never been measured continuously or confirmed during a commercial fermentation. As international interest increases in greenhouse gases, it is important to know the amount of CO2 release and the determining factors; yeast strain, temperature, and dissolved CO2 are potentially important parameters. The study was designed to quantify emissions and test a theoretical model for atmospheric release of CO2 during alcoholic fermentation in a commercial winery. Gas release was channeled through a manifold system with an in-line mass flow meter calibrated for CO2, providing real-time and integrated measurement of atmospheric emission. Intermittent use of a hot-wire anemometer was used as a check on the mass-flow measurements. Initial results indicate that integrated mass of CO2 release is dependent on total Brix decrease and not duration of fermentation, consistent with the Williams and Boulton model. However, the time course of release and the shape of the release curves differed substantially among ferments and were primarily dependent on the length of active fermentation

Quantifying Dissolved Carbon Dioxide Concentrations in Fermenting Red Musts

The concentration of dissolved carbon dioxide (DCOn2) is recognized as being high during alcoholic fermentation, but there is little data to indicate the actual concentrations and how they vary with extent of the fermentation or winemaking operations. The presence of the inert gas is important in protecting the juice or must from oxidation. In addition, carbon dioxide (COn2) is a recognized greenhouse gas, and the contribution of fermenting juice and musts to atmospheric COn2 cannot be put in perspective or modeled unless one has a better idea of DCOn2 and whether supersaturation is occurring throughout fermentation or for part of the time. This study monitored DCOn2 concentrations on a daily basis in four red musts during alcoholic fermentation in a commercial winery. Dissolved carbon dioxide concentrations generally peaked at around 2000 mg/L, but the maximum was not associated with a particular stage of fermentation. Musts tended to be supersaturated with DCOn2 when the rate of fermentation was high and/or the temperature increased rapidly and after a rack and return. Upon completion of alcoholic fermentation, DCOn2 concentrations generally decreased to between 400 and 1000 mg/L. During malolactic fermentation, DCOn2 concentrations varied between 1000 and 1500 mg/L

Gas/Particle Distribution of Polycyclic Aromatic Hydrocarbons in Coupled Outdoor/Indoor Atmospheres.

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

More space, better mathematics : is space a powerful tool or a cornerstone for understanding arithmetic?

Tight cognitive links between space and number processing exist. Usually, Spatial-Numerical Associations (SNAs) are interpreted causally: spatial capabilities are a cornerstone of math skill. We question this seemingly ubiquitous assumption. After presenting SNA taxonomy, we show that only some SNAs correlate with math skill. These correlations are not conclusive: (1) Their directions vary (stronger SNA relates sometimes to better, sometimes to poorer skill), (2) the correlations might be explained by mediator variables (e.g., SNA tasks involve cognitive control or reasoning), (3) the hypothetical course of causality is not resolved: For instance, contrary to conventional theories, arithmetic skills can underlie performance in some SNA tasks. However, benefits of SNA trainings on math skills seem to reinforce the claim of primary SNA role. Nevertheless, tasks used in such trainings may tap cognitive operations required in arithmetic, but not SNA representations themselves. Therefore, using space is a powerful tool rather than a cornerstone for math