Wines neutral

Ribereau-Gayon et al. (1976) emphasized that, in phosphatoferric casse, the wine does not become turbid due to clusters of ferric phosphate molecules, which are rather small and remain in the colloidal state in a clear solution. Turbidity, i.e. white casse, occurs when proteins, positively charged at the pH of wine, neutralize the negative charge of these phosphatoferric clusters, making them hydrophobic and therefore insoluble. Flocculation can only occur under these conditions. 

Catechins Tea, mustard cake, rapeseed some fruits and vegetables and wine Neutralize free radicals, reduce risk of cancer, protect the skin from UV radiation-induced damage... 

Phenolphthalein is another acid-base indicator. It is often used by magicians (and chemistry teachers) to perform a trick that turns water into wine. In acidic and neutral conditions, phenolphthalein is colorless and looks like water. A pH of approximately 8.3, however, turns phenolphthalein a deep reddish-violet color. In basic conditions, phenolphthalein looks like red wine. 

Among the numerous applications of SPE are separations of phenolic acids and flavonoids from wines and fruit juices. Sep-Pak Cig cartridges have been used for the fractionation of flavonol glycosides and phenolic compounds from cranberry juice into neutral and acidic parts before HPLC analysis. Antimutagenic flavonoids were identified in aqueous extracts of dry spinach after removal of lipophilic compounds by SPE. ... 

Other black substances are occasionally employed. Charcoal from various sources, when reduced to an impalpable powder, and mixed with the other ingredients, furnishes a deep blue-black ink that dries rapidly. Carbonized vine-stalks, wine-lies, woods of various kinds—in fact, carbonized lignin from any source, when ground sufficiently fine—sometimes a tedious and costly operation—answer well as also does bone-black. The brown tint possessed by lamp-black is not (infrequently neutralized by the addition of blue compounds, 3B indigo, Prussian blue, et cetera. 

The sodium and potassium salts of S02 are simpler and more pleasant to use as they do not have the odor of the pure liquid or the 5% water solution. They are rapidly soluble in must where they react with a small portion of the natural acid present to liberate S02. There are two sodium salts of S02 available, Na2S03 (neutral sodium sulfite) and NaHS03 (sodium acid sulfite). The latter compound introduces less sodium into the wine and removes less acid from the wine for an equivalent amount of S02 liberated. Potassium acid sulfite and potassium pyrosulfite (potassium metabisulfite) are the two salts of potassium with S02 that are readily available, soluble in grape juice, and capable of yielding S02 upon reaction with the acid of the juice. Potassium salt is recommended when it is desired to keep the wine low in sodium ion content for diet reasons. The salts should be edible or food product grade, that is, free of heavy metals and other toxic impurities. They must be stored in tightly closed containers or they will react with the water vapor and... 

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