Preserving Wine For Maximum Taste
It must be made clear at once that there should be no need to preserve well-made wines containing the maximum amount of alcohol. This is because there should be sufficient alcohol in the wine to preserve it.
However, it does sometimes happen that, in spite of good yeasts and a thoroughly good fermentation, the maximum alcohol is not made. It could be that you have missed the mark by as little as 1%. This may leave the wine less capable of combating disease, but it may also leave the yeast in a position to recommence fermentation, as we have just described.
Obviously before we go to the trouble of preserving wines it is as well to find out whether they are stable or not. If they are stable, then preserving is not necessary. But if, after the normal processes of fermentation, it is discovered that a wine is not stable, then preserving should be carried out. Either way, nothing in this line should be done until all fermentation has ceased in the normal way or until you are satisfied that the wine is a finished product ready to be put away to mature. Then, and only then, should the test be carried out to find whether the wine is stable or not. Users of the hydrometer should be able to verify whether they have made the maximum alcohol, so there should be no doubts for them. Even so, they may carry out the following simple test if only from the point of view of interest and practical experience.
Test for stability
Almost every chemist will let you have cheaply two small test-tubes with a rubber or cork stopper for one of them. Or perhaps firms dealing in home wine-making equipment retail these now, although they used not to. Two small asprin or other very small bottles will do if nothing else is available. Thoroughly sterilize and rinse the tubes or bottles and shake them free of as much water as you can. Dry thoroughly otherwise one or two drops of water will dilute the sample and give an inaccurate reaction.
Half-fill both vessels with the wines to be tested. Cork and seal one tightly. Cut a small piece of flat, stiff card to a little larger than the top of the second container and rest this on top of it. Stand the samples side by side in a warm room for twenty-four hours. If both samples are exactly the same colour after this then the wine is stable and need not be preserved. On the other hand, if the unsealed sample has turned a darker colour, the wine is unstable and should be preserved.
Preserving Dry wines
Thoroughly fermented-out, bone-dry wines, made with less sugar than produces the maximum alcohol, are another matter. All bone-dry wines are better for having a lower-than-average altohol content, although many people make them to contain the maximum. But when they have been made to contain less than 14% of alcohol by volume, preserving should be carried out. This is not because they are likely to ferment again. They cannot do this simply because there is no unfermented sugar left. But there is always a risk of the acetic change taking place unless they are preserved.
This is not to say that the acetic change is automatic or even likely but it can happen. The risk comes during siphoning or racking in some other way, when these wines are exposed to the risk of contamination by the acetic bacteria. Bear in mind that the weaker the wine, the more susceptible it is to disease. On the whole, if bone-dry wines are handled carefully throughout and kept in containers which are full, there should be no risk whatsoever.
Chemical preservation of Wine
Chemical preservation is undoubtedly the cheapest and most reliable method. This is practised by the trade on a far wider scale than is generally imagined. Almost all wines are preserved. The low-alcohol wines are preserved chemically, while the higher-alcohol ones, such as sherries and ports, are fortified (or strengthened) with added alcohol. If this were not the case, there would be no high-alcohol wines simply because the trade cannot produce more alcohol in their wines by the normal processes of fermentation than we amateurs can, except perhaps by as little as 1% or 2%.
Sherries have spirit added at the end of fermentation, but port and a good many other wines have it added quite early in the process. When port, for example, is being fermented, skilled tasters sample by taste and by testing apparatus to ascertain the amount of sugar used up, the strength of flavour, the general sweetness to the palate and so on. When all these things are satisfactory, large amounts of spirit are added. This kills the yeast and therefore halts fermentation, and at the same time fortifies the wine to the percentage of alcohol required.
That is why the high-alcohol wines are so robust, so full of flavour and have such wonderful aroma and bouquet. Only the natural sugar in the grapes has been fermented, whereas we have to add sugar to produce the amount of alcohol we want. And for this we must use cane sugar. The trade have no need to do this for they utilize only a certain amount of the sugar the grapes contain. The rest is left unfermented. The added alcohol brings out the flavour and bouquet to the full. The added alcohol is what we pay for in the more expensive wines. The cheaper sorts, being preserved chemically, cost far less to produce.
Campden tablets are used for chemical preservation, and it is quite a simple matter to treat any amount of wine, however large or small, in this way. A well-made wine with a good percentage of alcohol, but one shown to be unstable by the test already mentioned, should not need more than one Campden tablet to every 5 ltr (1 gall). Crush this to powder in a small cup or glass with something not metal, such as the handle of a wooden spoon. Mix a little wine with it and stir the sample into the bulk. Cork the jar for twenty-four hours and repeat the test described earlier. You will know from this test whether or not a further tablet is necessary.
Two tablets are usually the maximum needed. Indeed, where delicately flavoured wines are preserved in this fashion, more than one tablet would be likely to affect the flavour. Wines with a full flavour would not be affected by a little more. When preserving in this fashion we are using the permitted preservative of sulphur dioxide. The amount allowed by law in wines in this country is 450 parts of preservative to 1,000,000 parts wine. This amount is represented by eight Campden tablets. From this we see that, in using two or even three tablets, we are well within the safety limits.
It is often with the sweet wines that more than two tablets are needed, especially if their alcohol content is low. This is because they are very liable to refermentation and very susceptible to disease. It is always best, therefore, to strive to make the maximum alcohol when making sweet wines, unless, of course, you like low-alcohol sweet wines. In this case, make them and then preserve.
Preserving Wine with spirit
As mentioned, the higher-alcohol wines such as port are fortified during the process of fermentation not only to preserve them but also to retain their natural sugar content, to enhance their bouquet and to increase their alcohol content. This sort of thing is beyond the reach of the amateur because it is very expensive.
However we are able to increase the alcohol content by an important 2% or 3% at not too great expense when we have turned out exceptional wines worth preserving for themselves and keeping for many years. The addition of spirit will also bring about important improvements in aroma and bouquet during storage.
The trade use a number of brandies for this purpose, some of which are produced from the residue of a batch of perhaps thousands of gallons of wine — an enormous cake of skins and pips left after the wine has been drawn off. This cake is treated with water and allowed to ferment further. The resulting very poor wine, which has rather a low percentage of alcohol, is then distilled. Certain flavours and esters are allowed to come over during distillation so that this brandy has a flavour that makes it suitable for adding to a certain type of wine. But many brandies are produced which are quite neutral in both flavour and colour. This characteristic is often produced only by filtering the finished product through charcoal. When we talk of brandies, we immediately think of world-famous names, but almost all spirits distilled by the wine trade for fortification purposes are known as brandies.
It is with brandies quite neutral in both flavour and colour that we are likely to be interested. This is because when preserving wines we do not want to alter the colour or flavour of them. Rums, trade-named brandies such as the cognacs, whiskies and gins will all flavour wines and, in most cases, spoil them.
Imagine a well-made blackberry or elderberry wine with a hint of the flavour of rum, or even brandy for that matter. It would be quite out of character with the rest of the wine. It would be rather like taking good coffee and then detecting the taste of tea as you swallow it.
When fortifying or preserving, it is almost always best to use a spirit with neither colour or flavour. For this purpose, two grades of spirits are available: Polish pure spirit at 140° proof and vodka at 700 proof.
Before we go any further I think it is necessary to explain the difference between alcohol by volume and proof spirit, how these are compared with each other, and just what ‘proof means. This will clarify what is often one of the biggest mysteries confronting the average amateur.
When we refer to alcohol by volume, whether it be the amount in 250 ltr or 5 ltr, 50 gall or 1 gall, one bottle or half a glass, the percentage is the number of volumes of pure alcohol in each one hundred volumes of wine. Therefore, if we have half a glass of wine of 14% of alcohol by volume, we have fourteen volumes of pure alcohol in each hundred volumes. To put it another way, 100 ltr of the wine will contain 14 1 of pure alcohol, and 100 gall will contain 14 gall.
The term ‘proof is a relic of ancient times when there was no accurate means of measuring the amount of alcohol present in liquors. Hence the confusion these days when accuracy is essential.
A liquor that is 100° proof spirit actually contains only 57% by volume, which is just over half of what the average person might imagine it to be. Gin of 70° proof has the more accurate corresponding figure of 40% by volume. A spirit of 175° proof is actually 100% by volume — pure alcohol. The following table may be us’ eful. It does not cover the whole range as this is not necessary.
But it does cover the range which most amateurs may find useful for reference purposes from time to time.
When preserving with spirit, it is not necessary to add large amounts as all most of us want is to increase the alcohol content from the average of 14% by volume (24.5° proof) to about 16% by volume (28° proof). Indeed, this is all that is necessary for preservation purposes. You can, of course, increase the percentage further if you want to.
British standard wine bottles and those containing gin and whisky (full-size bottles that is) hold about 7.5 dl (26 fl oz) when filled to the usual level. However bottles, especially those from Continental countries, hold 6 dl (1 pt or 20 fl oz) or a fraction more according to the type of bottle. Those tall bottles without shoulders are usually this size.
The tables are designed for fortifying one bottle at a time as this is the most that the average wine-maker will want to start with. The best means of adding the spirit is to put it into an empty bottle and fill up with wine.
Where rather milder-flavoured wines are to be treated, and especially where more than 2 parts of vodka would be needed, some dilution of flavour is bound to result. It is therefore advisable to use a stronger spirit so that less is needed to do the job. The cost is the same whichever you use.