Fermentation, Theory of In the simplest chemical terms, one molecule of sugar is converted to two molecules of alcohol and two molecules of carbon dioxide, by the action of the yeast enzymes. Behind this statement lies a large number of chemical reactions. See Glycolysis , See Appendix IX.

Film Yeast A common cause of infection in a wine. The infection starts as small islands of white on the surface of the wine which gradually increase in size until the surface of the wine is covered with a whitish skin or pellicle. The effect of a film yeast is to convert the alcohol to carbon dioxide and water, and, therefore, once diagnosed, cure is urgently needed. By stirring, the pellicle is broken up, and sulphiting will kill the organisms. The wine is then racked after a few days. Prevention is by hygiene and anaerobic conditions. If, however, a sherry type wine is being made, do not break the flor.

Filter Funnel Any funnel with a folded filter paper will serve as a filter funnel. Its function is purely to retain the filter medium and deposit. For winemaking, filter papers tend to be too slow.

Filter Paper on of the possible media for use in filtering a wine. Their use in open funnels is taking an unnecessary risk with over-oxidation, especially as there are more efficient methods available.

Filter Pulp See Cellulose.

Filter, Rapid Another generic name for continuous filters.

Filter, Vacuum has the advantage of speeding filtration. Using an electric motor and carboy cap/clamp with a normal filter medium, pressure is created within the carboy.

Filtration and Asbestos In view of the dangers of its use, it is far better to use safe filter media such as cellulose. These work just as well and are not so liable to cause taints or lightening in the wine.

Filtration and Cellulose This non-toxic substance, and powders allied to it, have taken the place of asbestos as filter media. To use the pads or powders, the instructions given with them are followed. The first washings should be discarded in case they taint the wine with a filter paper taste

Filtration and Oxidation As in every stage of winemaking undertaken in the presence of air, there is a high risk of over-oxidation. This is especially true of filtration via funnels. On the other hand, closed filtration such as is achieved by wine kit filters, is obviously less prone to the problem. As with bottling, a wine develops a similar sickness after filtration from which it recovers after a few weeks. It is possible to create an oxygen-free atmosphere for filtration by filling the receiving carboy and filtration equipment with carbon dioxide from an actively fermenting carboy.

Filtration, Continuous Until recently filtration involved the laborious task of filling funnels at irregular intervals as the fluid levels dropped, but, with the advent of continuous filters, this hazardous job has been obviated. All the available filters are easy to use, hygienic and, above all, safe in producing clear wine when the instructions are followed.

Final Specific Gravity The specific gravity of the wine when fermentation has finished.

Fining Agent Any compound added to a wine to aid clearing. The common agents are dealt with under their respective headings: Bentonite, Gelatin, Super-Kleer, Isinglass, Sparkolloid Powder.

Fining Agents, Action of See Colloid ; See Iso-electric Point , See Sulphite and Clearing ; See Tannin and Clarification.

Fining Technique After a trial fining, the chosen agent is mixed to the right proportions and this is added to part of the wine and fully dispersed or dissolved as the case may be. This is then added to the bulk of the wine. After a week or so in a cool place, the wine will probably be clear and may then be racked off the deposit and maturation continued in the normal manner

Fining, Choice of Method Except in the use of bentonite, there is a danger of over-fining, and it is best, in order to avoid this, to perform a trial fining. Bentonite is the safest agent; after which comes super-kleer. Usually one of these two methods will clear a wine but, if not, one of the other methods will be tried until at least a partial success is achieved.

Fish Gelatin See Isinglass.

Flaming when removing a yeast culture from a container, sterility is essential. The neck of the container is sterilized by passing it quickly through the tip of a flame. If using a platinum loop, the loop must also be flamed before picking up yeast from an agar slope.

Flatness in a wine has several meanings, depending on the authority consulted. It may mean under acidity, lack of tannin, too little alcohol, or the wine may be too old. Thus is would appear to be a term to be avoided without defining the meaning. It is preferable to describe the fault.

Flavor The term used for the taste of a wine. In describing a flavor, it is important to describe what is tasted in terms understood by others. So, rather than using esoteric terms, relate the taste to a known food, flavor, etc.

Flavor, Medicinal The tangy taste to a wine which has too little acid. To prevent this fault it is important to add the correct amount of acid at the start. Once present, this off-flavor is impossible to eradicate.

Flavor, Metallic When a metal taints a wine it imparts a distinctive metallic taste to the wine. To prevent this the wine should not be allowed into contact with any metal other than stainless steel. Once present, a metallic taste is impossible to remove by amateur techniques.

Flavorings There are now many varieties of extracts and flavorings in the market with which it is possible to simulate most liqueurs and aperitifs.

Flor Formation, Conditions for Although the chemistry of flor formation is not yet fully understood, a few facts are known to influence its growth. The conditions favoring the development of a commercial flor are: Alcohol content between 14.5 - 15 percent PH between 3.1- 3.4 Tannin less than 0.03 mgs percent Sugar less than 150 mgs percent Sulfur dioxide a a 100 ppm The maturing fermenter should not have more than 24 inches of wine in it, with ideally, at least half as much space again for ullage.

Flower Wines Unblended, flowers produce thin wines with a good bouquet. Since they contain little nitrogen it is vital to add plenty of nutrients. To overcome the problem of thinness, Vinosity must be added either as raisins or grape concentrate. Flowers are also low in acid and tannin, and these must also be included.

Flowers are the reproductive parts of plants which an be recognized by the presence of sepals (green under petals), petals, stamens (spike-like structures in the center) and ovaries (seedpods). Their attraction to the winemaker is the scent they carry and which is used to add bouquet to a wine. One their own they make poor wines, as they are lacking in nutrients and vinous qualities. However, when used with other ingredients, they are an important item in many recipes.

Flowers for Bouquet See Bouquet, Flowers for

Flowers of Wine See Mycoderma Aceti.

Flowers, Boiling Do not boil flowers. Because most esters are volatile, boiling flowers will rive off the most important constituent - the aroma

Flowers, Preparation of Flowers do not contain much juice, so it is obvious that juice fermentation is not practical. Therefore, some modified form of pulp fermentation is needed. Like all natural produce flowers contain a large population of unwanted insects and bacteria. The insects can be removed by washing with cold water. The bacteria will be inhibited by proper conditions in the must. After about a week, when the primary ferment is over, flowers may be added. To add them sooner is to incur the same risks as boiling. When sufficient aroma has been extracted the flowers are removed from the must. To make this easier, the flowers can be placed in a bag prior to inclusion in the must.

Fly, Fruit See Drosophila Melanogaster.

Fly, Vinegar See Drosophila Melanogaster.

Formic Acid is the simplest of the organic acids, and is produced in small amounts during fermentation. Most of this is oxidized to carbonic acid to form part of the buffer system of the wine.

Fortification, Equipment needed Apart from a 100 ml calibrated jar, the equipment needed is that for alcohol measurement.

Fortified Spirit The commonly used fortifying spirits are vodka (alcool) or brandy. The former is more widely used due to availability and lower cost of production. Brandy should be used in the fortification of champagne, port, and madeira. See Super Yeast ; See Vodka.

Fractionating (or separating a solution into its component substances). The methods used are either those of distillation or freezing point differences. Alcohol both boils and freezes at a lower temperature than water. Thus by applying heat or cold to separate the two, the alcohol concentration can be raised. This is illegal without an excise license.

Freezing Mixture To reduce the pressure as well as to freeze a plug of wine containing yeast before degorgement, the neck of the bottle should be placed in a mixture of ice, salt and water. Alternatively, if available, solid carbon dioxide (dry ice) can be used instead of ice.

Frizzante The Italian word meaning a sparkling wine.

Fructose A hexose monosaccharide, one molecule of which together with one molecule of glucose forms the disaccharide sucrose. After inversion, the yeast can metabolize the fructose to alcohol. Sauternes yeast is interesting in that it metabolizes fructose more quickly than glucose, unlike most other wine yeasts where the converse is true.

Fruit Botanically, they are the female or seed-bearing parts of a plant. To the winemaker they are the edible parts of many plants, trees or bushes.

Fruit Fly See Drosophila Melanogaster

Fruit Juice All plants have some juice in them, but, for the winemaker, fruit are considered juicy only if easily expressed in large volumes (e.g. citrus fruit have juice, while bananas do not). Depending on the volume of expressible juice, the method of fermentation is decided.

Fruit Pressing Depending on the fruit used, wine style intended and fermentation method selected, the timing of pressing will vary. Most fruits have some free run juice (the juice obtainable when the skin is broken). On the other hand, the marc will contain large volumes trapped between the particles of fruit. To obtain this juice, the fruit is pressed. The technique is simple û the fruit is compressed until the juice runs. When all the juice has flowed from the first press, increase the pressure. Do not put on maximum pressure at the start, as this will wreck the press and lessen the yield. Do not over press fruit. The last pressings do not make quality wines, often due to the tannins and glycosides which are not extracted until the pips and twigs are pressed.

Fruit Pulp is prepared by shredding fruit in a pulper or food processor (providing it is not made of a haze-producing metal). The pressing of pulp rather than the whole fruit will yield a greater volume of juice.

Fruit Types Taking "fruit", incorrectly, to include all ingredients. See Elder ; See Hard Fruit ; See Herbs ; See Leaf ; See Rhubarb ; See Soft Fruit ; See Vegetables.

Fruit Wines Any non-poisonous fruit can be used to make wine, either on its own or as a blend. The method of preparation, fermentation and the style of wine depends on the type of fruit selected. Fruit wines are now made easier by using a self-contained fruit wine kits such as Bru-Berries.