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More and more people are growing hybrid grapes and finding out that the wine made from them rivals the noble European grape varieties of Vitis vinifera. But to make great wines from hybrid grapes means that winemakers have to vary their techniques to match the varieties they are working with.
Hybrid grape varieties are a blend of native American grape species and V. vinifera varieties from Europe. The American species found in these hybrid grapes make them more disease resistant and winter hardy. Unfortunately, they also tend to be higher in acid and less balanced and this presents some difficulty when making wine.
This doesn't mean that great wines can't be made though, it just means that they are a different beast from what most winemakers are accustomed to. They're just different and have to be manipulated to produce wine that is acceptable. Modifications in your winemaking methods are necessary to take advantage of the hybrid grape's characteristics.
Making Red Wine From Hybrid Grapes
Most red hybrid grape varieties tend to be more highly colored and have higher acid content than their V. vinifera counterparts. Sugar, measured in Brix, varies among the various varieties and is often dependent upon the genetic make up and what American species are found in their parentage.
Varieties with V. labrusca tend to have lower sugar at maturity than V. vinifera varieties while varieties with V. riparia and V. rupestris often will reach sugar contents well into the 20 Brix readings. Acid levels can often be as high as 9-14 g/l. This is what becomes a challenge to the winemaker when making wine from these hybrids.
The fruit from many of the hybrid varieties tends to be more like their American parents. Small clusters and small berries. This means that the berries often have a high skin to pulp ratio and many varieties have colored juice. Subsequent wines have intense color, especially when compared to traditional wines made from V. vinifera varieties.
Most hybrid grape varieties need only 2-5 days on the skins during the primary fermentation to product good color. The cap should be "punched" two to three times a day to achieve this. Extending the time of contact with the skins will result in deeply intense color but has the drawback of increasing herbaceous off flavors and other flavor compounds that are seen as unacceptable in the finished wine. If you do get herbaceous flavors, you will need to age the wine 3-4 years to tame them.
Dealing with the high levels of acids found with hybrid grapes presents the greatest challenge. There are various means of manipulating the winemaking process to overcome this problem. The first is to ameliorate the must with water before fermentation. Amelioration can result in a lighter bodied wine with less fruit characteristics. This also results in a flatter taste.
Some winemakers stop the fermentation before it reaches dryness or sweeten the finished wine. The residual sugar ads body and mouthfeel to the wine. It also enhances the perception of fruit and reduces the perception of acid in the finished wine. Since most hybrid grape varieties are low in tannins, this gives palate balance to the wine.
A more traditional method for dealing with the high acidity of hybrid grapes is to encourage malolactic fermentation with a malolactic bacterial culture to reduce the acidity. This is added when the primary fermentation is nearing completion but not quite finished. The fermenter should be kept close to 70F or slightly more to encourage the bacteria to grow and do their thing. A longer retention time of the wine on the lees will also encourage malolactic fermentation.
Deacidification with potassium bicarbonate is another method for reducing the high acids in hybrid grape wine. This can be done prior to fermentation or after completion. Calcium carbonate is not recommended for this as it can create off flavors and are often considered unpleasant in the resulting wine.
Potassium bicarbonate should be added in increments to prevent excessive deacidification or production of off flavors. I suggest an initial deacidification prior to fermentation, then testing the acidity after malolactic fermentation and deacidification if the acid is still too high.
Cold stabilization at temperatures cooler than 40F but higher than freezing for a couple of weeks to a month is recommended for all red wines made from hybrid grapes. This will precipitate out the "cream of tartar" from the wine and further reduce the acidity. The acidity should be checked again after cold stabilization and if to high, another addition of potassium bicarbonate should be added.
Red wines made from hybrid grape varieties can be oaked to give them more tannins. Most hybrid grapes are low in tannins and this will aid them as well as give the wine flavor.
One tip to making a good hybrid grape wine is that the best wines come from blending varieties to give balance and make up for the deficiencies of the various pure varietal wines. Blending can be done with finished wines. Blend small amounts to get the ratio of the blend before blending bulk amounts. Once you find good blends, you can blend varieties prior to fermentation in the future.
Making Rose Wines From Hybrid Grapes
Because of the intense color that red varieties of hybrid grapes have, grapes should be immediately pressed after crushing to make a rose wine. You may even have to add some white varieties to attain the rose color you're looking for.
All the above methods for reducing acidity should be followed to produce a balanced rose from hybrid grape varieties. Acidity is always the devil when it comes to making hybrid grape rose wines.
Making White Wines From Hybrid Grapes
White wine varieties should be crushed and pressed immediately and fermentation begun after adjusting the acidity. Many white varieties need to be harvested at a low sugar level to limit off (labrusca) flavors. Therefore they will be high in acidity.
Sugar may need to be added to bring the Brix readings up to where you want them. In very fruity varieties, amelioration with sugar water will aid with both the sugar content and relive some of the acid problem. But be careful if you do this as it may make for a flat tasting wine.
Otherwise, all the above methods for reducing acidity should be followed. Malolactic fermentation should be experimented with as you will find that in some wines it produces a beneficial softness to the wine but is objectionable in other white hybrid wines.
With the right manipulation of your winemaking parameters, you will make fine wines from your hybrid grapes that are comparable to the wines of Europe and California. In fact, many wines from hybrid grape varieties have won awards over their V. vinifera parents. It just takes making your wines with the right adjustments and finesse.
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