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Calcium
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Calcium
is a metal. In winemaking it is important in lowering the pH of
water. Under normal circumstances tap water has sufficient calcium
in it for winemaking, except when making sherry. Since sherry must
need to be of a lower pH than other wines, calcium has to be added
as gypsum. After fermentation has finished most of the calcium
present precipitates out of solution as insoluble calcium salts.
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Calcium
Carbonate
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Calcium
Carbonate is a chemical substance whose use in winemaking is one
of the standard methods of reducing acidity. The addition of + oz
(7 grams) per gallon will lower the acidity by about 1.5 ppt of
sulfuric acid. The reaction involves the formation of insoluble
calcium salts and the giving off of carbon dioxide. So beware of
foaming.
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Campden
Tablets
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Campden Tablets contain about 450 mg of
potassium (or sodium) metabisulphite. These are added crushed and
are used as sterilizing agents. The usual rate is two tablets per
gallon for sterilizing the must; the same at the first racking;
and one tablet at successive rackings. The actions of
metabisulphite are dealt with under Sulphite and Sterilizing.
See
Sterilizers
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Caramelisation
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Caramelisation
The term used to describe the taste of madeira-like wines which,
due to the heating process involved in their manufacture, develop
a burnt sugar (or caramel) taste.
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Carbon
Dioxide
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Carbon
Dioxide is nature's waste product. In almost all chemical
reactions in nature resulting in waste it is carbon dioxide which
is that product. This holds true for winemaking where the
conversion of sugar to alcohol results in an equal weight of
carbon dioxide being given off. This is, unless a sparkling wine
is being produced, a waste product, although it helps protect
against infection.
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Cask
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Cask
Another term for wooden storage vessels for wine. There is no
doubt that oak casks are the best containers for a quality wine
but unfortunately their high cost precludes their routine use.
Even in France their use is dying out since, sad to say, there are
no longer any craftsmen who can make, maintain or repair those
beautiful fermentation vats so often seen in pictures. Instead,
with modern progress, the use of stainless steel or plastic, has
taken the place of wood.
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Cask
Care
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Cask
Care More than any piece of equipment do casks require close
attention. The wood of a cask left empty for any time will shrink
with the result that the hoops and staves will become loose. Casks
not cleaned immediately after use will rapidly acquire taints
difficult to eradicate. Thus, the cardinal rule of using casks is
to ensure cleanliness and always to refill the cask within an hour
or two of emptying it. If not refilling it with wine, it should be
partially filled with sterilizing solution
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Cask
Cleaning
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Cask
Cleaning Immediately after emptying, a cask must be cleaned out,
otherwise it may become tainted. All that is required are general
washes with tap water to ensure that all sediment has been
removed. The cask can then be sterilized for re-use.
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Cask
Maturing
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Cask
Maturing is accepted as being the best method of maturing wine.
Any winemaker concerned with quality production is well advised to
have at least one barrel for just this purpose. Maturing in cask
firstly fulfils the axiom that bulk maturing is better than
maturing in small volumes. Secondly, the wood has pores in it
large enough to allow the passage of air while excluding bacteria.
The size of these pores is such that a continuous stream of air
can reach the wine at a rate which will ensure an optimum rate of
oxidative changes. This is obviously preferable to the wine
receiving massive does of air at racking, with concomitant changes
of over-oxidation. Thirdly, the wood and wine exchange substances
to the ultimate effect of the wine.
See
Maturing.
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Cask,
Oxidation
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Cask,
Oxidation in Since wood has pores through which air can enter the
wine, a wine matured in the wood will always be receiving some
oxygen to allow oxidative changes to take place. The rate of
reaction depends on the ratio of air entering the wine to the
volume of the wine. Thus in a large cask the air supply may be
insufficient so that regular rackings are required to augment the
oxygen reaching the wine. This problem is unlikely to be met with
in amateur cask sizes, since they are usually less than 12
gallons. If anything, the opposite is more likely to occur, since
the small casks used mean a large surface/volume ratio, so that
the wine is in fact in danger of over-oxidation. To prevent this
careful judgment is needed to gauge the optimum length of cask
maturing. Once a wine is clear, it should not be racked (this may
cause over-oxidation) unless removing the wine from a deposit.
White wines are less robust than reds and cannot withstand long
periods of cask maturing. Depending on the tannin content of a red
wine, it may be capable of withstanding several years' cask
maturing; a white wine on the other hand, will spoil and become
over-oxidized after only a few months. For sherry-type wines,
prolonged oxidation is a required feature of their production.
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Cask,
Preparation for use
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Cask,
Preparation for use After ensuring that the hoops are tight, a new
barrel requires the staves to be swollen by filling it for 24-48
hours with water. This is followed by hot soda washes until the
water comes out clear. The soda is then rinsed out with tap water.
After sterilizing with bisulphite, 5 grams per gallon, the barrel is
ready for use.
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Cask,
Ullage
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Cask,
Ullage Due to the loss of contents by evaporation, an air-space
develops above the wine in a cask, which is known as ullage.
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Casks,
Sterilization
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Casks,
Sterilization of The old method of burning sulfur wicks inside the
barrel has been superseded by the use of sulphite, since burning
sulfur tends to drip, and these may confer a "bad egg"
flavor to the wine. The 5 percent stock sulphite solution is quite
adequate
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Casse
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Casse
A discoloration of a wine due to enzyme or metallic contamination
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Casse,
Metallic
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Casse,
Metallic Cooper, lead, tin and iron will, if allowed contact with
a wine, cause a haze and discoloration in the wine, which will
also have a marked metallic taste. If lead is suspected as the
contaminant, the wine must be discarded, since lead is highly
toxic. This usually affects wine as the result of using old
earthenware vessels with a soft glaze. It is sometimes possible to
remove an iron haze by the use of bentonite and tannin finings.
Prevention of any metallic casse is by avoiding the use of metal
containers except those known to be safe.
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Casse,
Oxidassic
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Casse,
Oxidassic Another term for oxidative casse.
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Casse,
Oxidative Wines
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Casse,
Oxidative Wines made from over-ripe fruit, especially pears and
apples, contain large amounts of an enzyme called
o-polyphenoloxidase which has the action of oxidizing tannins to
brown pigments; hence the discoloration. Prevention is by
immediate sulphiting of prepared fruit. Cure is by sulphiting the
wine with 50-100 ppt sulphite every 2-3 months until the problem
is overcome (an instance of sulphite being used as an
anti-oxidant). The sulphite will take up the oxygen before the
enzyme, and so prevent the fault developing further.
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Cellulose
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Cellulose
is the main building block in the plant kingdom, akin to protein
in animals. It is composed of long chains of glucose. Enzymes
capable of breaking it down are rare û mostly they are secreted
by putrefactive bacteria, such as those which cause the sweet
smell of decaying grass. However, there is now available to the
amateur an enzymatic preparation Rohament P which is able to
break down connective tissue in plants (this is composed chiefly
of cellulose). By breaking down the plant to this extent, the
yield of juice is increased.
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Cellulose
Filtration
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Cellulose
Filtration Cellulose is now the standard filtering agent to the
winemaker and the key component of most modern filter pads for
simple filter systems. See
Cellulose.
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Chalk
Chalk,
Reducing Acidity with
Champagne
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Champagne
The sparkling wine. Credits for its developments are given to the
monk, Dom Perignon, who invented Champagne corks to preserve the
fizz, and to the Widow Cliquot, who invented the pupitre and
remuage. Most likely, its development is related to the drinking
of wines much younger than now, to minimize the chance of
acetification, and the discovery that carbon dioxide (present in
any wine still fermenting when bottled) masked some of the faults
of older wines.
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Champagne
Bottles
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Champagne
Bottles Because of the pressures encountered in commercial
Champagne the bottles are thicker and heavier than ordinary wine
bottles. It cannot be stressed strongly enough that champagne-type
wines must not be put into wine or damaged sparkling wine bottles.
Always check bottles for flaws whether scratches or chips; if
present, discard that bottle. If in doubt about a sparkling wine
bottle, do not use it.
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Champagne
Bottles, Pressure in Commercially
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Champagne
Bottles, Pressure in Commercially, this is between 70 and 90
pounds per square inch (psi). But, for amateur winemakers, it is
recommended that the pressure should not exceed 50 psi. Firstly,
there is a danger in working with these wines, particularly when
disgorging, and secondly, the bottles may have flaws unsuspected
by the winemaker. With common sense and care, however, the chance
of danger are very small.
See
Champagne
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Charcoal
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Charcoal
is one of the purest forms of carbon. It is very active chemically
and can combine with most dyes and esters so that, if used for
fining, care must be taken not to use too much in case a white,
tasteless liquid is all that is left.
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Charmat
Process
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Charmat
Process A method of making sparkling wines frowned upon by the
Champenois. It entails the second fermentation taking place in a
sealed tank.
See
Cuvee Close.
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Chitin
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Chitin
a polysaccharide and principal component of fungi.
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Chitosan
The
natural product, Chitosan is derived from Chitin, a polysaccharide found
in the exoskeleton of shellfish, such as shrimp or crab. It works as a
protein
attracting oppositely charged particles to combine
and settle to the bottom of the container.
Citric
Acid
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Citric
Acid Until the recent advent on the winemaking scene of cheap
supplies of other acids, citric acid was the winemaker's staple.
Its main use is that it aids in healthy ferment and also has good
antiseptic properties. For maturing purposes it is almost useless
since it is not utilized in ester formation. Thus it is not
recommended for use on its own. However, for the beginner not
wishing to delve into the mysteries of the other acids its use in
the correct amounts is not to be sneered at. It will give a
pleasant acid character to a wine and lemonade.
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Citrus
Peel and Inhibition
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Citrus
Peel and Inhibition Do not use too much peel of citrus fruit in
the must. It contains an oil which forms a layer on the surface of
the must, thus preventing oxygen access to acid establishment of a
fermenting yeast colony.
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Clarification
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Clarification
The stage of wine production that immediately follows fermentation
when, by gravitational and electrical forces, the cloudiness of a
wine gradually lessens until a star bright wine is seen. On
occasions, luckily rare, the wine refuses to clear on its own and
other methods have to be resorted to, to obtain a clear wine. To
avoid the need for fining requires the use of the proper enzymes
at the start of fermentation. If, despite their use, a cloudy wine
remains, fining and filtering are then indicated.
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Classification
of Sugars
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Classification
of Sugars Sugars are classified by the number of carbon atoms in
their basic sugar unit (i.e., a hexose has 6 carbon units), and by
the number of units of basic sugar that comprise one molecule of
the sugar. For example, glucose is a hexose monosaccharide (it has
a single unit of six carbons in its molecule). On the other hand,
sucrose is a hexose disaccharide, since it has two units of six
carbons in its structure.
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Classification
of Wines
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Classification
of Wines Wines are classified accordingly to type; aperitif,
social, table or dessert; color; red, white, rose, brown or
golden; and sweetness; dry, medium or sweet.
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Cleaning
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Cleaning
The first step to the production of sound wines is scrupulous
cleanliness in everything which includes oneself as well as all
the equipment one uses.
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Cleaning
Agents
Cleaning
Casks
Cleaning
Equipment
Clearing
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Clearing
The term used to describe the falling out from suspension of yeast
debris and other sediments in the wine. Some of this occurs by
gravity; i.e., fruit pulp and yeast; some by coagulation; i.e.,
protein-tannin complexes; and other compounds may have to be
persuaded out of solution by various means, such as fining and
filtering.
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Clinitest
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Clinitest
A test reagent in tablet form which measure the concentration of
glucose in the wine. It is essential in the making of sparkling
wines to know the residual sugar before dosage. The method of use
is described under Sugar Estimation in Wine. Usually found in most
pharmacies. Also known as Dextro-Check.
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Clostridium
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Clostridium
Species of bacteria, one of which causes tetanus or lockjaw. These
bacteria are especially resistant to many of the sterilizing
agents because, as spore forming bacteria, they can defend
themselves from many of the bacteriocidal agents. They are only
killed by very high temperatures maintained for long periods. They
are, however, prevented from reproducing if the pH is below 4.5.
Thus, to ensure a must or equipment free from these bacteria, it
is necessary to assay the pH, since the practicality of
autoclaving equipment is beyond the amateur. Of course, it would
destroy the wine to heat it or its ingredients for any length of
time.
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Closures,
Plastic
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Closures,
Plastic Useful re-usable corks which are usually flanged. They
vary from almost flat such as are used with crown caps, to bottle
and champagne types. It is most important to ensure that they are
of a good fit to prevent seepage.
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Cloth,
Pressing
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Cloth,
Pressing Muslin or terylene cloth of a fine weave which is used to
wrap fruit before placing it in the press. If no cloth is used
great difficulty may be experienced in cleaning the press after
use as the pulp will be forced into the cracks and drainage holes.
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Cloth,
Straining
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Cloth,
Straining Any fine weave cloth containing no dyes or starch is
ideal. Its purpose is to restrain particles of fruit pulp from
entering the fermentation vessel after pressing the fruit.
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Cold
Extraction
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Cold
Extraction To minimize pectin extraction, and prevent undue
destruction of volatile oils the use of cold water and pectic
enzyme is advised for most ingredients. The method is to place the
crushed fruit in a volume of cold water about equal to half the
final neutralize excess chlorine in the water. To aid extraction,
pectin and cellulose destroying enzymes are added. If desired,
pulp fermentation can then follow. The type of fruit to which this
method is suited are: apples, citrus fruit, peaches, pears and
rhubarb.
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Collage
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Collage
A French word meaning fining.
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Collagen
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Collagen
An animal protein which when boiled is altered to gelatin, a
fining agent
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Collagenous
Protein
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Collagenous
Protein Any protein which can be degraded to gelatin by heating.
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Colloids
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Colloids
Some substances, when placed in a liquid, are not soluble and,
instead of falling to the bottom of the container, as would, say,
chalk, remain floating. For this to happen, the substance must be
finely ground with a particle size between one-thousandth and
one-millionth of a centimeter. The particles (or dispersed phase)
have an electrical charge, which acts like similar poles of a
magnet and repel each other. Because of this effect, the particles
remain in colloidal suspension and form a haze. Protein is the
common cause of such a fault. In winemaking, the main colloidal
fining agent is Bentonite, which forms a lyophobic colloid (the
wine and bentonite do not have an affinity for each other and will
not combine together chemically). If there is protein present, the
negatively charged bentonite will be attracted to the positively
charged protein. They will form electrically neutral particles
which, as well as being too large to remain in suspension, no
longer have the repelling charges, and fall out of suspension to
produce a clear wine.
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Color
Extraction
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Color
Extraction Obtaining the correct depth of color in a must is one
of the most important steps in the production of wines. For white
wines, the only required action is the use of the right quantities
of ingredients. For red wines it is usual to ferment initially on
the fruit pulp before straining the must when the necessary depth
of color has been achieved. Rose wines, being light red wine, need
less pulp fermentation. The usual length of time required for red
wines is between 5 and 7 days; and for roses, between a few hours
and 2 days, depending on the depth of color required.
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Color
of Wine
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Color
of Wine is normally limited to white, rose or red. Some dessert
wines may be golden or brown in color; as may be sherries. White
and rose are fairly obvious colors, but red has a wide range of
shades, all of which are correct within the meaning of the term.
Some poor quality reds may be similar in color to a blackcurrant
juice, while a newly made claret may be so dark as to appear
almost black ( a shade often likened to mahogany). This color
fades gradually to a shade sometimes called brick red. An orange
color in a wine may be due to a failed attempt to blend a red wine
and a white wine to obtain a rose; green is not an uncommon shade
in a young white wine and is due to the presence of chlorophyll. A
brown color in a white table wine is often due to oxidation. See
Diagnosis of Faults; Appendix XI.
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Color,
Wrong
Coloring
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Coloring
The color of a wine depends on the amount of fruit, and its color,
used in the preparation of that wine. If it is discovered that a
wine is not the correct color, and blending is not a practical
solution, there are a variety of coloring agents available to try
to obtain the correct tone. Should a wine be too intense in color,
then blending with a neutral topping-up type of wine will possibly
overcome the problem. It is rare for a red wine to be too dark in
color.
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Commercial
Imitations
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Commercial
Imitations Amateur winemakers can now easily emulate many
commercial products using any of the quality, pre-packaged wine
ingredient kits on the market. By careful analysis of the taste
and characteristics of a commercial wine, it is possible to blend
raw ingredients or add adjuncts to formulated wine kits to produce
a reasonable facsimile of any commercial wine type.
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Competitions
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Competitions
are now frequent occurrence in the winemaker's diary. Apart from
prizewinning, there is always plenty to learn from the judge's
comments, and this should bring about an improvement in one's
standards. When entering a competition, be careful to study the
rules and obey them, otherwise that prizewinning wine will be
marked down, maybe because there was only a small rule broken,
such as the wrong amount of air space in the bottle.
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Composition
of Wine
Concentrate
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Concentrate,
Grape One of the major advances in food technology is the ability
to condense and sterilize a juice to a S.G. of maybe 400 without
losing any of the volatile aromatic constituents. There are many
firms now marketing grape concentrates, from which excellent wines
are made. The basic method of concentrating a juice and, at the
same time, retaining the flavor, is by using the technique known
as vacuum evaporation. This entails, as the term implies, the
lowering of the pressure in the boiling container so that the
boiling point of the juice is also lowered. By boiling at a lower
temperature, less of the volatile oils are driven off, since the
temperature can be lowered below their boiling point.
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Conditioning
Casks
Congeneric
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Congeneric
These are the higher alcohols and esters present in a wine or
spirit responsible for conferring bouquet and flavor on the drink.
In distilling spirits the congenerics can be altered by changing
the technique of distillation.
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[Return
to Index]
Containers
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Containers
Any winemaking utensil, usually closable either by its lid or with
a bung or airlock, used for fermenting or maturing wines. Any
non-reactive material is safe.
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Containers,
Earthenware
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Containers,
Earthenware Until recently, the traditional amateur winemaking
fermenter. However, due to rising costs, the fact that one is
unable to see what is happening within and, far more important,
the danger of using a jar glazed with lead based glazes, they are
going out of use to a great extent. These are toxic since the lead
will be leached into the wine.
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Containers,
Glass
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Containers,
Glass These are undoubtedly the best. They are easy to clean, and
since they are transparent it is possible to inspect the contents.
Due to the ease of cleaning, they are equally easy to sterilize
and, most important, they are to all intents non-reactive. Thus no
ingredients can attack the glass and destroy it or cause
off-flavors û not all plastic are safe from this. Do not keep
wine in clear glass containers in direct sunlight.
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Containers,
Glazing of
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Containers,
Glazing of Many old earthenware containers are glazed using a
lead-based glaze, which can be recognized by its softness. The
salt-based glazes are safe from toxic effects, and these do not
indent with pressure. Lead is a toxic metal and should not be
allowed into contact with wine.
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Containers,
Plastic
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Containers,
Plastic Provided the plastic is of a "food grade", it is
quite safe to use for fermentation, since it is guaranteed
non-toxic.
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Containers,
Stoneware
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Containers,
Stoneware Synonymous with Earthenware.
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Continuous
Filters
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