Spontaneous clarification

After completion of the alcoholic fermentation in tanks or barrels, wine becomes a colloidal solution as well as a colloidal suspension. The particle density, which is close to that of the wine, electric repulsion forces and diffusion phenomena lead to very slow and insufficient spontaneous clarification. Moreover, natural... 

Oak barrels are commonly used in the aging of wine and spirits because of their positive effects, which include increased color stability, spontaneous clarification and a more complex aroma. 

Heating the must also results in poor spontaneous clarification of the resultant wines due to denaturation of the pectic enzymes (Peynaud, 1984). The addition of exogenous pectic enzyme preparations, usually of microbial origin, overcomes this problem. 

Heating grapes destroys the natural pectolytic enzymes of the grape and so spontaneous clarification of new wines is difficult. This circumstance intensifies potential gustatory flaws. Adding commercial pectolytic enzymes can resolve this problem, but their effectiveness varies. 

Although the ability to cope with complex mixtures of fuels may be some way off, dealing with alkane mixtures is certainly within our grasp. However, there appears to be one key aspect that requires clarification. From the evidence in Section 6.4, it is clear that the longer chain n-alkanes, such as n-heptane, can undergo spontaneous ignition at very low-temperatures. This is in marked contrast to the lower reactivity of the shorter n-alkane chains such as n-butane, or of highly branched isomers... 

We can find out whether a proposed reaction is possible by determining whether it is a spontaneous thermodynamic process. In this context, spontaneous has a precise technical meaning (see later for clarification) that should not be confused with its conversational meaning, such as describing the spontaneous behavior of people in social situations. Thermodynamics can tell us whether a proposed reaction is possible under particular conditions even before we attempt the reaction. If the reaction is spontaneous, thermodynamics can also predict the ratio of products and reactants at equilibrium. But, we cannot use thermodynamics to predict the rate of a spontaneous reaction or how long it will take to reach equilibrium. These questions are the subject of chemical kinetics. To obtain a large amount of product from a spontaneous reaction in a short time, we need a reaction that is spontaneous and fast. 

Substantial progress towards the improvement of the activity of the aminoglycosides was made by the clarification of the enzymatic inactivation mechanisms of aminoglycoside by resistant organisms. The formation of those enzymes which inactivate aminoglycosides is determined by episomal genes. This type of resistance is therefore called episomal resistance or R-factor mediated resistance, which can be transferred between bacteria cells, but not by spontaneous mutation. 

The wine should be properly clarified prior to flat-sheet filtration at the time of bottling to ensure a satisfactory flow rate. This preliminary clarification may involve spontaneous settling, fining, centrifugation (Section 11.11) or filtration through a diatomaceous earth precoat (Section 11.6). 

The [4+2] cycloaddition certainly represents one of the most important reactions in organic chemistry, and many books and reviews are dedicated to this field.23 Theoretical studies were undertaken, since such an enormous amount of experimental data has been collected that a clear and general view is not obtained readily. Some clarification came with the classification of the reactions in three types according to the electronic demand.24 Besides the theoretical complexity, the experimental conditions are not always easily optimized some reactions occur spontaneously, others need catalysis, pressure and/or heating, encouraging investigators to find improvements by using new activation methods.25... 

So the teacher and elass explore the idea that solids are hard , with the students spontaneously offering points of view in responding to what others have said. The teacher helps sustain the diseussion both in terms of enabling students to eontribute ( other people are desperate to say -, can you say it to the front ) and in making requests for points of substantive clarification (give me an example -, so you think... ). 

Extensive studies on the chemical structure of the Tay-Sachs ganglioside have not shown a significant abnormality. As mentioned earlier, a compound with identical structure has been found among brain gangliosides of normal subjects. However, the sensitivity of these complex molecules toward treatment with alkali or acid, the possibility of spontaneous hydrolysis during handling and the complicated methods of structural identification render definite clarification of this point difficult. 

The kinetics of spontaneous dry white wine fermentation are fairly haphazard. The speed and degree of completion of fermentation vary, depending on the indigenous strain present. In addition, clarification un-inoculates juice to a certain degree. A slow fermentation due to a low yeast population can result. Sometimes quality wild microtiora can produce spontaneous fermentations with excellent results. Selection of wine yeast strains began by isolating strains with successful spontaneous fermentations. 

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