Disorders that could well be avoided

Appears in

Metallic casse Metallic taste and haze, wine turns brown. Discard immediately as it is slightly poisonous and has a cumulative effect. Probable cause is the use of iron, copper, chipped enamel or lead-glazed stone containers.

Oxidasic casse Wine turns brown with almond smell.

Tests
  1. take two glasses of wine, one treated with sulphite (one Campden tablet) and one untreated, and expose to air overnight. The untreated wine will darken.
  2. Critic acid will not affect the rate of browning.
Treatment if not severe
1 to 2 Campden tablets per gallon, repeat every 2-3 months.

Medicinal flavour Caused by insufficient acid in the original must. Added citric acid may help, but if pronounced, discard the wine.

Musty flavour Caused by leaving a wine on the lees, particularly baker’s yeast. Regular racking, say every other month, may assist, but if pronounced, discard the wine.

Flatness or insipidity Caused by insufficient tannin. Add 1 teaspoon of very strong tea per gallon/4.5 litres.

Thinness (lack of body) Blend the wine. Initially add grain to thin fruits like plums, bananas or sultanas to table wines.

Pectin haze The test for the presence of pectin is to take 3fl.oz/75ml methylated spirits and 1 fl.oz/25ml wine. Mix them well, and if jelly-like clots or strings begin to form, the wine should be treated by stirring in 1 teaspoon of one of the proprietory brands of pectic enzyme. Keep the wine in the warm for a few days, then rack, or filter if the haze does not clear.

Starch haze If its presence is suspected, place a few drops of the wine on to a white tile or plate. Add two or three drops of iodine. If the mixture contains black spots or flecks, then starch is present. The treatment for this is quite complicated.

Put ½oz/15g amylase, 3fl.oz/75ml water in bottle and leave for 2 hours, stirring and shaking. Heat the wine to 170°F/82°C and hold at this temperature for 20 minutes. Cool to 100°F/37°C and stir in the diluted enzyme. In an hour the reaction should be complete. Again raise the temperature to 170°F/82°C and hold for 10 minutes. After cooling, the haze should settle out, and then the wine should be racked.
Disorders during fermentation:

Acetification (or formation of vinegar) This is probably the most disastrous disorder, caused by the presence of air, very bad storage, the vinegar fly or heat. Excessive heat is something which is not often considered, but remember that the cap of a fermenting must is at least 5°F hotter than the rest of the must. If the heat is too great it will kill the yeast, but still remain at an ideal temperature for any bacteria to multiply. Be careful never to use a container contaminated by vinegar such as a barrel, or plastic container. The treatment, and it is only effective in the very early stages, is to add 2 Campden tablets per gallon/4.5 litres, leave for 24 hours, then re-start with a yeast starter of similar yeast, gradually building up until all the wine is re-fermenting. This will drive off most of the acetic acid in the carbon dioxide. If it is noticed in a finished wine, there is little one can do. Remove it from contact with other wines. It will gradually turn completely to a wine vinegar, but if this cannot be used, discard it.

Flowers of wine Caused by a film yeast, and normally develops in a still wine, firstly small white patches appear on the surface of the wine, increasing until a grey/white wrinkled skin covers the surface. The treatment is two Campden tablets per gallon/4.5 litres. The wrinkled skin will gradually sink to the bottom, when the wine can be racked into a sterilized container. A second treatment may be necessary in a light wine, but it is not worth retaining the wine if the alcoholic content falls below 10%.

Rope A bacteria which forms short rods or chains, held together by a slimy substance. Treatment is simple. Add two Campden tablets per gallon/4.5 litres, stir vigorously, then rack off carefully. Do not keep the wine but drink it soon.

Tourne disease This leaves an excessive bitter taste in the wine, and it will have a silky sheen or cloud. If the off-flavour persists, discard the wine.

The following recipes all include the preparation of a yeast starter. In winemaking, the most dangerous time for infection is until the fermenting yeast has formed a ‘blanket’ of carbon dioxide over the must. Anything that can be done to shorten this period is really worthwhile, so a mini-ferment should be made up which is placed in the bucket with the other ingredients as soon as it is working fully. A starter bottle can be made up as follows:
Mix in the yeast and yeast nutrient according to instructions on the packet and keep in a warm place until it is fully fermenting which will take about 24–48 hours.

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