Indicator A chemical compound which alters color with a change in pH. By using one which changes color at the neutral pH of 7, acidity measurement can be accurately performed.

Infusion The soaking of ingredients in a medium known to dissolve the required flavors, color, etc. The making of many liqueurs and aperitifs requires the extraction of substances soluble only in alcohol or in water at temperatures which would volatilize them. Obviously, infusion in an alcohol solution (i.e., wine) is the method to use.

Ingredient Any vegetable, fruit, leaf or flower known to be non-poisonous is acceptable as an ingredient. To these basic ingredients must be added sugar, acids, additives and yeast.

Ingredient, Blending The purpose of blending is to attempt to improve on shortcomings in ingredients. For example, flowers on their own make thin wines, so that blending with an ingredient known to give a good body will improve the finished wine. Since nearly all commercial wines are blended at some time in their lives, there is no stigma attached to blending country wines.

Inoculation The addition of yeast to a must.

Inorganic Constituents of Wine See Metals ; See Salts ; See Sulphur ; See Water.

Insipidity A tasting term used to describe a wine lacking in character. It is usually due to a lack of acid or tannin. A tasting term used to describe a wine lacking in character. It is usually due to a lack of acid or tannin

Inversion of Sugar The first stage in the utilization of sucrose by yeast is the splitting of the disaccharide into two mono-Saccharides. This is accomplished by the enzyme invertase. If desired, inversion can be achieved by boiling the sugar in water to which a small amount of acid, citric or tartaric, has been added. This is not a necessary step to taken since any wine yeast is capable of inverting sucrose.

Invert Sugar See Sugar, Invert.

Ionization When an atom dissociates in solution it becomes ionized and each atom or radical becomes electrically charged. If hydrogen ions predominate the solution is acid; if hydroxyl ions, it is alkaline.

Iron need never come into contact with wine. If it does, it will cause a haze difficult or even impossible to remove. If present, it is usually due to the use of chipped or cracked enamel ware. The haze may be colored with a blue tinge or it may be white.

Iron Haze Removal 5 percent citric acid in 10 percent sulphite solution, or 5 percent tannic acid solution, may clear the wine. A trial fining is required before scale treatment. If this fails, it is best to discard the wine.

Iron, Tests for (a) Add a few drops of sulphite. The formation of a yellow precipitate indicates a possible iron haze. (b) The formation of a turbidity within 24 hours of adding hydrogen peroxide means that a wine may develop an iron haze. (c) Quantan (cf).

Ismoer Organic compounds are three-dimensions structures. Because of this, arrangement of their atoms in the molecule can vary, although the chemical formula remains the same. For a simple analogy to an isomer look in the mirror, while examining a recent photograph, and note the differences