Bacteria and Acidity A must which has an adequate acidity to achieve a balanced wine will have, in general, an acidity sufficient to kill or inhibit bacteria. However, wines being complex buffer systems, the titratable acidity is not a guarantee of a low enough pH to control infection. A pH of between 3 and 4 at the start of fermentation will prevent infection. The usual range of titratable acidities lies between 4 and 8, depending on wine style

Bacteria and Alcohol Bacteria not killed by Sulfite are killed by alcohol in fairly low concentrations. Those surviving initial sulphiting will be killed by the alcohol of fermentation. If fermentation is delayed it will allow inhibited bacteria time to re-establish themselves.

Bacteria and Heat All bacteria killed by high temperatures; so for equipment this is the best sterilizing method, if made of glass. Heat is of use for certain types of ingredient which can be boiled safely.

Bacteria and pH Most bacteria can survive only if the pH is between 3 and 7 and this fact may be made use of in hygiene. Therefore, assaying the must prior to pitching the yeast will, in most cases, prevent infection. A starting pH of between 3 and 4 will kill spoilage bacteria whilst not preventing the reproduction of yeast.

Bacteria and Sulphite It is no accident that sulphite is the winemaker's major agent against infection; it does not harm fruit and will either kill or neutralize bacteria. At the same time, it does not harm wine yeasts unless in very high concentrations.

Bacteria Resistance If attempts are made to kill or inhibit bacteria with too low a concentration of sterilizing agents there is a danger that the bacteria will not be killed or inhibited, but will instead learn to tolerate that substance. This is resistance. The danger exits that the bacteria may actually thrive on the chosen agent, so that its continued use may in fact be dangerous to the cleanliness of the winery. The bacteria may possess the ability to break down the agent (this is common in medicine, but not winemaking) or it may be able to develop new metabolic pathways.

Bacteria, Acetifying are present on all rotting fruit, so sound fruit is the first step to a non-acetic wine. An uncovered must, due to the presence of sugar and fermentation, will attract the fruit fly which, as a carrier of acetifying bacteria, will cause the change of wine to vinegar, and therefore all wines, no matter what stage they are in, must be covered.

Bacteria, Aerobic These bacteria require air to survive and multiply so that, once a must has been sterilized, protection from access of air and airborne bacteria is essential, either by an air lock or polythene sheeting over the fermentation vat. The blanket of carbon dioxide over an active ferment will do much to prevent the entry of aerobes but , once the ferment slows, the danger is real and requires careful attention to hygiene and exclusion of air. Usually infection can be suspected if a haze accompanied by an off flavor develops. If tests for infection are positive the wine should be sterilized with sulphite and, after racking, restarted.

Bacteria, Anaerobic These bacteria thrive in the absence of air and, therefore, unlike aerobes, need more than exclusion of air for prevention of troubles. They are, however, killed by sulphite and therefore the use of this at racking times will prevent them getting a foothold, presuming a hygienic fermentation. Lactobacilli responsible for the malo-lactic reaction, are, under controlled conditions, beneficial anti-aerobes.

Bacteria, Lactic Acid are the main anaerobic bacteria the winemaker will come across.

Bacteria, Lactic Acid and Malo-Lactic Fermentation If, at bottling time, the wine is not sulphited, a slightly sparkling wine may be produced. This is due to the action of the lactobacilli which, at this stage of the wine, break down malic acid to lactic acid and, in the process, give off carbon dioxide, this causes the sparkle. This reaction is aimed for in some commercial wines. The end result of the reaction is a less acid wine, due to the less acid taste of lactic compared to malic acid.   

Bacteria, Lactic Acid and Ropiness Some of the lactobacilli species multiply and stick together forming long chains which can be seen in the wine. Due to the mucus the bacterial secrete on their surface, the wine becomes thick and oily. Prevention is by hygiene and the cure, if needed, is to sulphite the wine, stir it thoroughly to break up the chains, and allow the wine to settle before filtering. Usually there is no associated off-flavor developed with this condition and, once treated, the wine should be drunk soon after filtering.

Bacteria, Lactic Acid and Spoilage Some of the lactobacilli contain the enzyme lactase, which breaks down sugar to lactic acid and, at the same time, may produce curious off-flavors, usually described as mousey or rancid. They may also produce acetic acid. Their metabolism of sugar to lactic acid will also reduce the potential alcohol yield.

Bacteria, Protection against is basically very simple HYGIENE. At all stages of winemaking, equipment, must or wine are sterilized, or precautions taken against the introduction of infection. The major sterilizing agents to the winemaker are: acidity, alcohol, heat, pH and sulphite. After preparation of the must and its sterilization an air lock is required; at racking sulphite or ascorbic acid are used; and at all stages the equipment is scrupulously cleaned and sterilized before use

Bacteriocidal is an adjective applied to a substance which has the property of killing bacteria. For winemakers the bacteriocidal agents are sulphite, alcohol and heat.

Bacteriostatic A term applied to a substance which inhibits the growth of bacteria without necessarily killing them. Such effects may be seen when using too little sulphite. However, some organisms are not killed by sulphite, but they are inhibited from further growth û a static effect, and these are killed by the alcohol as it is formed. Care needs to be taken over the possibility of resistance.

Baker's Yeast Although having a reasonable alcohol tolerance of about 12 percent, it has the property of giving off large volumes of carbon dioxide. If used as a wine yeast there will tend to be a rapid frothy ferment which clears slowly and leaves loose, easily disturbed lees. For beginners, the quick ferment is useful encouragement to further ventures, as it does prove that fermentation occurs even if a superior wine is not produced.

Balance for Weighing A beam balance is more accurate for weighing than a spring balance for several reasons, but in winemaking a high degree of accuracy is only needed when measuring the small amounts of additives required and, in these circumstances, a stock solution is the easiest way to accuracy. In normal circumstances, the ordinary kitchen scales are accurate enough for our purposes

Balance in a Must A balanced wine is one in which all the taste factors are equal and no single one is dominant; i.e., the wine is balanced. To achieve this the ingredients, additives and nutrients required to attain this end must be brought together from the beginning in the must, and it is this ability to foresee the taste of a wine in five or six years time that distinguishes the ordinary from the expert.

Balling The American scale used in the measurement of Specific Gravity. See Appendix VI.

Barrels The traditional (and, until recently, the only) storage method for wines and beers. See Cask entries.   

Base A chemical term for a substance which turns litmus blue (i.e., it is alkaline) and also reacts with an acid to form a salt and water. When used of an acid, it refers to the number of hydrogen atoms one molecule of the acid has available for forming hydrogen ions. Thus a dibasic acid has two hydrogen atoms which can dissociate from the molecule

BDH Universal Indicator A mixture of weak acids which change their colors with changes in pH. By adding a small amount to a sample of unknown pH the green color of the indicator alters to a shade which varies with the pH. The range of this solution is from pH 3 to 12

Beet Sugar extracted from the white beet is estimated to be the source of over two-thirds of the household (and winemaking) sugar used today. Chemically, the sugar is as pure as cane sugar, although the French champagne producers claim it confers an earthy flavor if used for chaptalisation.

Bentonite Gel A proprietary form of bentonite which has the advantage that it is easily put into solution

Benzene A chemical compound having 6 carbon atoms joined together in a ring structure which, when various radicals are added to it, form many of the compounds encountered in winemaking; e.g. tannin

Bisulphite When metabisulphite is added to water it forms bisulphate, and this, after other chemical reactions, results in the liberation of sulfur dioxide gas, the winemaking sterilizing agent.  See Sterilizers

Bitterness A term used to describe the off flavor associated with infection by the lactobacilli which produce mannitol (despite its bitter taste, it is a sugar). Tourne disease is another name given to this condition. Although the infection can be cleared by the use of sulphite, the off flavor arising from the infection is not so easily eradicated and, if blending fails to provide the solution, the wine will have to be discarded.

Blending for Body Man country wines are made from ingredients that on their own produce thin wines; hence the inclusion of recipes of grape concentrate, raisins or bananas, all of which add to the body of a wine without overpowering the flavor of the main ingredient.

Bottle Brushes A self-descriptive piece of equipment for cleaning bottles. Varying in size, they will clean airlocks to demijohns.  See Vintner-s Deluxe Starter Kit  

Bouquet The term used to cover the description of the smell or aroma of a wine. Under normal conditions, this is the result of ester formation from succinic and malic acids joining with alcohol. These esters are fragrant, volatile compounds which, when the wine is slightly warmed, evaporate into the air above the wine, where they should be trapped in the glass so that the bouquet can be enjoyed. If a wine has an unpleasant bouquet infection can be suspected. For optimum ester and, therefore, bouquet development time is the essential factor, although the use of flower petals can confer a pleasing bouquet in a shorter time.

Bouquet, Blending for See Blending for Bouquet.

Bungs are either of plastic or rubber. Whilst economic in that they can be used repeatedly, they are not ideal for maturing purposes, for which cork stoppers only should be used. (The small amount of air that can pass through works wonders on the quality of the wine.)  See Vintner-s Deluxe Starter Kit   See Bungs