Spoilage Can Be Prevented In Wines
When you realize the number of troubles that can beset the wine-maker, you might well ask how on earth he ever manages to make good wines. The simple answer is that he has come to realize that prevention of troubles is better than attempts to cure the result, and he works accordingly. Therefore he has no trouble.
But there are people making wines who often have them turn to vinegar; go insipid and flat; take on odours that have nothing to do with the decomposition of vegetable matter and dead yeast cells; become sharp or apparently over-acid on storage; have medicinal flavours; become thick and oily; become harsh of flavour and assume an overpowering or sickly bouquet; or become sickly sweet to the palate. All these troubles, besides a few that are peculiar to individual wine-makers, are quite easily avoided. But without understanding the causes, no one would know the preventive measures that are necessary.
Most modern methods in circulation include the necessary precautions but, unfortunately, many redundant methods are still used, and countless recipes and methods from our grandparents’ day are still current. Indeed, even in these enlightened times, a few magazines still pump out these antiquities. Their editors, always on the lookout for simple methods for their readers, refuse to believe that modern methods can turn out wines superior to many with long names and expensive pedigrees from the Continent. So the poor reader has little chance of success. Anybody with the right kind of recipe, using the right method and having a little background knowledge, can turn out wines comparable with those from almost any country you care to name. And almost the whole of the secret of success lies in preventing wines from being spoiled.
Any method that calls for gathering the fruits and then letting them ferment without added yeast should be put on the fire at once. And so should any that do not call for sterilizing the fruit either by boiling or by using sulphite (Campden tablets), whether added yeast is recommended or not. This is because the gathered fruits already have yeasts in them. Some of them may be quite useful, but with them almost invariably come many wild (uncultivated) spoilage yeasts.
In addition to the wild yeasts, several species of bacteria and moulds are also present. If the must is not sterilized by one means or another, any of these can set up a fermentation of sorts alongside the fermentation brought about by the desirable yeast we add, so that any of the troubles mentioned above can occur very readily.
Acetification, or wine turning to vinegar, is one of the most common troubles. Although it is possible to halt this disease in its stride if detected very “early, it is rare that the trouble is discovered until irreparable damage has been done. Acetification is caused by the vinegar bacteria, Mycoderma aceti. Having gained access to the wine or having been present on damaged fruit, the bacteria convert the alcohol produced into acetic acid which is the main constituent of vinegar.
Lactic acid bacteria, of which there are many species, are the cause of many troubles, including ropiness or oiliness. Wines afflicted with this disease take on an oily appearance and may indeed pour like oil. The flavour is impaired, but not to a great extent. However, the conditions and the dppearance of the wine make it quite unpalatable.
You can cure this trouble by dissolving one and a half to two Campden tablets in each 5 ltr (1 gall) of wine and stirring it vigorously for several minutes. If you leave the wine for some time, the deposit settles out in a similar way to an ordinary deposit, but this one is usually of loose consistency and is easily disturbed. Some people seem content to drink a wine revived in this fashion, but to my mind the disease and the drastic treatment it requires renders a wine not worth having.
Sweet to semi-sweet wines are sometimes attacked by a species of lactic bacteria which feeds upon the sugar to produce a number of by-products which impart a peculiar off flavour, bitterness, or a very difficult to describe sickly sweetness to the wine.
This is not the same as an over-sweet wine; the sweetness appears in the after-taste rather than on the tongue. Often with these wines there are also other flavours which cannot be described as there are so many of them. And a most surprising fact is that I have had this sort of affected wine offered me at various places (no names, no pack drill) by people who simply could not detect their presence. Obviously, the disease was in its early stages, but within a few days the wine would be irretrievably lost.
Finished dry wines are not affected by lactic bacteria because of the absence of sugar. But careless production could allow the trouble to run alongside
it, is responsible for hazes that appear in wines at later stages. They are rarely seen until the wine has been stored and then brought out for use. Ordinary clarifiers have little or no effect on these hazes, and you usually have to resort to filtering. This can very easily cause oxidation, or the absorption of too much oxygen.
Metals, in addition to causing hazes, impart disagreeable flavours; many wines do, indeed, take on a medicinal flavour. When drinking the wine, you may think that you are taking some sort of iron tonic instead. You can rid the wines of their hazes but the flavours persist.
Sterilizing The Wine Making Equipment
There is no doubt that in the past — and in the present also where negligence is encountered — almost all spoilage of wines was caused by not sterilizing the initial must or utensils. Sterilizing the must is included in any good method, so there is no need to mention it here.
However, sterilization of the must is useless in preventing spoilage if we neglect to sterilize all the utensils, including bottles, corks, hydrometers and their flasks, fermenting vessels, jars and funnels. This is because the diseases which attack wines are everywhere, in the same way as those that attack humans.
Wine, like the human body, is very susceptible to attacks by bacteria. But, unlike the human body, wine has no natural means of combating attacks. In other words, there are no antibodies present in wines capable of fighting disease as there are in the human body. Every utensil must be regarded as a likely source of infection by one of the many diseases of wines. They must be sterilized in a similar fashion to the instruments used for surgical operations on the human body.
Fortunately, this is a very simple matter, which fits into the general plan of wine-making without inconvenience of any sort. To be able to do this with a minimum of bother, and to have plenty of sterilizing solution always on hand in case unexpected bottling or racking become necessary at short notice, it is important to have a stock of sulphur dioxide solution. Sulphur dioxide is undoubtedly the most reliable means of sterilization and is used by the trade. Indeed, cellars where wines are bottled are fumigated with sulphur.
Bear in mind that the many bacteria that cause disease in wine are in the air and therefore likely to be inside jars and bottles, on corks and so on. And it is a fact that many people are careless in their wine-making to the extent that they actually attract the disease to their products. Fermenting musts left uncovered, small amounts of wine or lees left in bottles or jars, fruit pulps from the straining bag, and vessels put away without being cleaned of all traces of wine — all these attract disease.
Put the pulp from a strained must outside the back door and within a few minutes there will be at least a dozen fruit flies buzzing around it. These are harmless in themselves, but they act as carriers for other diseases, especially the disease caused by acetic bacteria which convert alcohol to vinegar. For this reason, these flies are wrongly called ‘vinegar flies’. Attract these flies near to the house and in minutes they will be inside if they smell wines. And if you happen to be performing some operation that necessitates exposing wines to the air for a little while, they will be after the wine like a shot.
The same applies to other bacteria. The spores of wild or spoilage yeasts and moulds are always present and are often seen in colonies as white or grey patches on jams or cheeses left exposed, on jars of meat paste, and in dirty wine and beer bottlts. This being the case, yeasts and moulds must also be present on utensils, corks and so on. Though inactive they are ready to become active as soon as a medium suitable for them comes into contact with the utensils. Wine, of course, is a very suitable medium. Destruction of all these likely causes of disease is clearly necessary if trouble is to be avoided.
Sulphur dioxide is a gas. We can produce it in aqueous solution, and therefore in a very convenient form to use, by dissolving metabisulphite crystals in water. Small amounts of solution may be produced in an emergency from Campden fruit-preserving tablets used for sterilizing fruit musts, but this method is not suitable for use with a large amount of utensils or even for repeated use on small amounts. It is far better and cheaper to make a stock solution.
I find 2 ½ ltr (½ gall) of solution a very convenient amount, but half this amount would be more suitable for many people. To make 2 ½ ltr (½ gall), buy 100 g (4 oz) of sodium or potassium metabisulphite crystals from a chemist. Do not accept this if it is lumpy as it is very difficult to break down. Dissolve the crystals in about 1 litre (1 ¾ pt) of warm water, stirring with something nonmetal such as wooden spoon, until all the crystals have dissolved. Then make up to 2 ½ ltr (½ gall) with cold water. To make the smaller amount, halve the quantities.
Corked well, the solution will keep its potency for as long as six months. It has rather a suffocating smell. However the only means of testing whether it is still strong enough after long storage and repeated use is to smell it. Do not take a powerful sniff at close quarters or at the neck of the jar. Approach it carefully, taking repeated sniffs as you get closer. All the time there is a strong smell of sulphur, the solution is suitable for use. Being so cheap, there is no excuse for using the solution once it has lost its power.
When sterilizing bottles, jars and so on, put about 1.5 dl (¼ pt) of solution into the first bottle or about 6 dl to a 5 ltr jar (1 pt per 1 gall jar), and shake the bottle (or jar) well so that all the inside is wetted. Then pour the solution into
the next bottle, and so on until all have been treated. After you have finished, return the solution to the bulk for further use. Treat bottles and jars as they are required for use, and use them as soon as they have been treated. Before putting wine into them, drain them of solution and rinse them inside with a little, cool, boiled water.
Sulphite solution is intended mainly for use with vessels and utensils that cannot be boiled, such as glass and plastic. But it is also useful for other things as well. Straining cloths, for example, can be sterilized with it. Afterwards they should be wrung out as dry as possible and shaken well before use. Spoons and small implements, however, are best sterilized by dipping in boiling water.
When removing bungs from stored wine or removing a fermentation lock and bung, it is a wise precaution to wipe round the bung, and then the whole of the jar with a cloth well wetted with sulphite solution. This is because while the jars have been standing, dust, bacteria, yeast and mould spores will have been collecting on the surfaces. These can very easily contaminate the wine if precautions are not taken.