Fining agent

Analogous reactions occur for Sb203 and for other nitrates. These reactions release copious quantities of NO and O2, which form large bubbles which rapidly rise to the surface. These bubbles stir the batch and sweep smaller bubbles to the surface. 

After batch decomposition is completed, melts are usually heated to higher temperatures and held until completely fined. Since the trioxide is more stable than the pentoxide at these temperatures, the pentoxide produced via reaction with nitrates decomposes via the reaction  

The equilibrium expressed by Eq. 3.5 is very temperature-dependent. Lowering the temperature will result in a shift toward the pentoxide, which requires absorption of oxygen from the melt. As the dissolved oxygen is consumed, oxygen from nearby bubbles will diffuse into the melt, reducing their internal pressure and hence reducing their diameter. Once the diameter is reduced to a very small value ( 0.1 mm), the surface energy will become sufficient to cause contraction of the bubble and a rise in internal pressure, P, as described by the expression  

Although other fining agents are usually less efficient, the toxicity of arsenic and antimony oxides often force the use of other approaches to chemical fining. Sodium sulfate, for example, also serves as a source of 

The SO2 molecules diffuse into nearby bubbles, while the O2 either diffuses into bubbles or dissolves into the melt. These bubbles then rise to the melt surface. Lowering the temperature can result in reabsorption of SO2 from bubbles to form sulfate chemically dissolved in the melt, which will cause the bubbles to shrink and disappear in a manner similar to that described for arsenic and antimony fining. 

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Incipient hazes may not be removed at all by simple filtration. An array of fining procedures have been developed to achieve stable clarity in such cases. Fining agents ate substances that ate or become insoluble in wines, and, as they precipitate, adsorb or coptecipitation incipient sources of cloudiness. Ptopedy used, the fining agents themselves ate not retained in the wines and thein effect is subtractive rather than additive. 

Loss on ignition. GeneraUy, the oxides of carbon and sulfur (plus some chlorine, depending on the fining agent) volatilize during melting. 

Antimony trioxide and sodium antimonate are added to specialty glasses as decolorizing and fining agents, and are used as opacifiers in porcelain enamels. Antimony oxides are used as white pigments in paints, whereas antimony trisulfide and pentasulfide yield black, vermilHon, yeUow, and orange... 

Schbnungsmittel, n. fining agent, fining (for colors) brightening agent. 

Sami-Manchado, P. et al.. Analysis and characterization of wine condensed tannins precipitated by proteins used as fining agent in enology. Am. J. Enol. Viticult., 50, 81, 1999. 

Goertges, S. and Haubrich, H. (1992). [Fining agents and their effects on the treatment of fruit juice and wine.] Schonungsmittel und ihre Effekte bei der Saft-und Weinbehandlung. 

Hahn, G. D. and Possmann, P. (1977). Colloidal silicon dioxide as a fining agent for wine. Am.. Enol. Vitic. 28,108-112. 

Quality control audit of incoming process materials such as filter powder, organic acids, cleaning agents, filter pads, fining agents, etc. 

Eder, R., Brandes, W., and Paar, E. (2002a). Influence of grape rot and fining agents on the contents of biogenic amines in musts and wines. Mitt. Klosterneuburg 52, 204-217. 

Fish and products thereof, except fish gelatin used as fining agent in beer and wine... 

Fining also may be done to juice prior to fermentation. Protein fining agents may be used to reduce phenolics in press juice, or bentonite used for protein reduction or reduction of potential for hydrogen sulfide (H2S) production (18). 

Fining is a winemaking technique used to enhance sensory or clarity properties of the wines. Common fining agents used with North Coast white wines are bentonite (a clay), casein (milk protein), gelatin (animal protein),... 

In most Interior Valley winery operations, the wines are racked once. After this racking, the wines are fined. This is a clarification process carried out by use of certain fining agents that cause flocculation and settling out of any cloudiness in wine. In addition, certain colloidal and proteinaceous soluble solids are absorbed by the fining agent. If not removed by fining, these soluble materials may later precipitate out in the bottle and cloud the wine. 

Commonly used fining agents in the Interior Valley are bentonite, gelatin, and certain proprietary agents. The major fining agent is bentonite, which is used as a slurry at the rate of four to ten pounds per 1000 gallons of wine. 

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