Harshness A tasting term to denote a wine in which an alcohol taste is predominant.

Haze A misty appearance in a wine.

Haze, Bacterial Any wine which is infected will eventually show a haze due to the sheer numbers of bacteria in it. It is possible to clear such a wine by sulphiting the wine followed by racking, first to kill and then to rid the wine of the bacteria. See Diagnosis of Faults, Appendix XI.

Haze, Colored Metallic Most metal salts, and it is the salts which cause wine hazes, are colored. Thus any colored haze in a wine should be suspected of being due to a metal. The metals commonly affecting wines are: iron, lead, copper and zinc. See Diagnosis of Faults, Appendix XI.

Haze, Pectin Most fruits contain some pectin. As pectin is more soluble in hot water the use of boiling techniques is not recommended for fruits. Unless pectin enzymes are used, the pectin, which is not broken down to any extent by yeast, will form a haze. See Diagnosis of Faults, Appendix XI.

Heat for Sterilizing Do not heat to sterilize plastics û most of them melt at high temperatures. If using this technique for glassware, bake equipment in the vent at a temperature of 150¦C (300¦F) for one hour. A sulphite solution is preferred. See Sterilization.

Heat, Color Extraction by While a reasonable technique for preparing grape concentrates, it is not recommended for must preparation, since the use of heat is likely to confer a cooked taste on the wine. The exception to this is in the preparation of vegetables.

Heater, Immersion See Immersion Heater.

Herbs, Preparation of Pour boiling water over the herbs (dried or fresh) to sterilize them and, after blending with the must, extract sufficient flavor by pulp fermentation.

Hexokinase Once sugar has been broken down to glucose and fructose, the glucose is then split into two molecules of trioses by this enzyme.

Hexose Any sugar containing six carbon atoms in its structure, i.e., glucose and fructose.

Higher Alcohols See Fusel Oils.

Honey is the basic ingredient of mead. It is the form in which bees store foodstuff, obtained from the pollens of flowers. Since it is high in bacterial contamination, it is essential to ensure sterility by boiling or, preferably, with sulphite.

Hydrocarbon A compound composed of hydrogen and carbon. None of these compounds is involved in winemaking as such, but some of them (benzene and the phenols) for the basis of tannins and plant pigments

Hydrogen The simplest element known to man. It plays an important role in winemaking from being a component of alcohol and water to role in pH and acidity.

Hydrogen and Reduction See Reduction.

Hydrogen Ion When hydrogen enters solution it undergoes a change known as ionization as a result of which it becomes acidic. By measuring the concentration of hydrogen ions in a solution the pH is obtained.

Hydrogen Ion Concentration See pH.

Hydrogen Peroxide The addition of this reagent to a wine containing iron will cause cloudiness. The reaction may take 24 hours.

Hydrogen Sulphide The once smelled never to be forgotten stink of rotten eggs. If a wine is racked and sulphited to stop fermentation early, the yeast may reduce the sulfur dioxide to hydrogen sulphide. The other cause of this off aroma is the use of sulfur wicks to sterilize barrels. The sulfur may drip on to the wood, impregnate it and then undergo the same reduction. If such a smell is noticed, the cure is to add 100 ppm sulphite at monthly intervals until the smell disappears. The mechanism of this cure is the formation and precipitation of sulfur from the interaction of hydrogen sulphide and sulfur dioxide.

Hydrolysis A chemical reaction wherein the elements of water are added to a compound. It usually requires an enzyme to catalyze the reaction

Hydrometer and Alcohol Measurement Most winemaking hydrometers have a potential alcohol scale on them. This is useful to the beginner but not quite accurate since these scales presume that fermentation continues to dryness and are not usually corrected for the presence of insoluables in the wine or must.  See Determining Alcohol Content

Hydrometer Errors If the temperature is not that marked on the instrument the reading will have to be corrected according to the table in VII. The other common cause of error is not reading the scale correctly. The true S.G. is taken at the level of the liquid and not the height to which it rises by surface tension. You cannot get a reading by placing a hydrometer in a glass carboy. The thickness of the glass neck distorts the reading.  See Hydrometer Corrections

Hydrometer, Use of Fruit juices after pressing should have their S.G. measured to assess the natural sugar content. (38 units on the scale equals one pound of cane sugar.) From this the amount required to reach the starting gravity can be calculated.  See Using a Hydrometer

Hygiene See Cleaning ; See Sterilization.

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