Types of Grapes and their Preparation for the Australian Home Winemaker
Over many thousands of years, grapes have been selected for a number of different purposes, as there are quite considerable differences in the varieties grown.
The characteristics that distinguish good wine-making grapes are small berries, plenty of flavour in the juice and (in the case of red wine varieties), colour and flavour in the skins. Table grape varieties have large, lush berries with think skins, which make them less suitable for wine-making.
Red wine types
The best varieties for making red wines are Cabernet Sauvignon, Shiraz (Syrah or Hermitage), Grenache, or Matara. Of these, Grenache is the easiest to obtain, average in quality, and if grown in non-irrigated conditions, will give a good red wine. Another advantage of Grenache is that, because it is comparatively low in acid and tannin, is quick to mature. This is important when you are starting off, as you want to try your wine before twelve months to see if it is worthwhile carrying out a second vintage. Even if Cabernet or Shiraz are available, it is still advisable to use a blend with Grenache at least for the first year. If only easting varieties, such as Black Prince, are available, you may have to be satisfied with producing a light red wine or rosé unless you improve it with some Shiraz or Grenache. Even as little as 20% of these varieties will improve the colour and flavour greatly.
White Wine Types
The remarks about red wines also apply to white varieties. The wine produced from varieties such as Rhine Riesling or Tokay, will be much better than that made from sultanas or Gordos, two common domestic varieties. It is not so easy to improve these with the top white varieties, as their flavour is more subtle. It is best either to make a light red from Sultanas or Gordos with a mixture of Grenache or else ferment with the skins. This is not the traditional way of making white wines, and the wine will be amber in colour rather than clear, but it will have much more flavour than wine made from pure Sultana juice.
When crushed, a tonne of grapes will produce about 120 – 150 gallons of juice and skins, but much less finished wine. It is hard to estimate the exact quantity, as it will depend on the efficiency of the pressing, but it would be wise to count on no more than 100 gallons per ton. To make it easier for conversion, for every gallon of wine you want to produce, you’ll need 10 kg of grapes. This is important because you’ll have to calculate backwards from the capacity of barrels or vats available to the quantity of grapes required to fill them.
Crushing your Grapes
White wines are the easiest to deal with as you only need the juice, unless you want to experiment with an unconventional Sultana wine fermented on the skins, in which case you treat it as a red. The juice can be extracted on a small scale with a juice extractor or, on a larger scale, with a cage press.
For white wines, a beater or roller crusher is only a refinement that makes use of the press quicker and easier but is not a substitute.
For red wines, you need to crush the berries to extract the juice, and then to ferment the skins and the juice together. The stalks should be removed as they add an excessive bitter tannin flavour to the wine. In large wineries this is done with a beater crusher, which is a device with beaters rotating at high speed over a coarse sieve (the holes about 2 cm in diameter. The berries are crushed and pass through the sieve to a pit below, while a slight spiral on the beater works the stalks out at one end. It would be impossible to modify this for home use at a reasonable cost, so it is better to crush and de-stalk separately. Crushing can be done in a bucket with a stick, using rollers from a mangle or washing machine wringer mounted sideways, or the cage press.
For the Australian home winemaker (or any home winemaker for that matter), there are a number of grape varieties that are available to turn into a fantastic vintage. Although the preparation required to turn the grapes into wine is quite extensive and labour intensive, the reward for your hard work will be a fantastic wine that you and your friends can enjoy over a nice dinner.