Handling Frontenac isn’t difficult; it’s just different. Fortunately, these differences can be manipulated to produce a variety of wine styles, making the grape more flexible than many. This allows the production of several marketable styles from one crop, and gives the winemaker options in years when the growing season has been less than optimal. Modifications in winemaking method are necessary to take advantage of Frontenac’s four variations from traditional wine grapes: it is more highly colored than most V. vinifera, it has higher soluble solids and acid content, and it tends to have low tannin.

Like the fruit of its V. riparia ancestors, Frontenac berries are small, have high skin-to-pulp ratios, and tend to have colored pulp. These traits result in intense juice color. For rosé production, this means that immediate crushing and pressing, without the few hours of skin time allowed in traditional rosé production, results in a rich, bright rose-colored juice. Frontenac rosé pigments have proven to be very stable, with little or no color loss during fermentation, and no fading as the wine ages. Tavel enthusiasts may dislike the color intensity, but attempts to lighten it by fining have so far resulted in faded wines with hues of sickly salmon. Until research reveals the exact nature of the grape’s pigmentation, it may be best to accept the color as a unique and impressive feature.

For red wine production, 2-5 days of ambient skin time, with caps punched thrice daily, generally produces appropriate color. (It’s important to note that pre-fermentation pectinase addition is not recommended, as it tends to turn the must into a slimy mess and inhibits good cap formation.) In experimental and commercial production, skin contact has been extended for as long as 7 days, but the resulting deepening of color and increase of herbaceous aroma and flavor compounds has been deemed unacceptable by some taste panels when evaluated a year or two post bottling. Later tastings suggest that herbaceous characteristics come back into balance by 3 or 4 years, but additional work is needed to determine the validity of this assessment. In informal aging trials, red Frontenac wines aged up to 10 years have shown no discernable decrease in color intensity, suggesting that phenolic polymerization is minimal. Research is currently underway to determine the nature of phenolic compounds in the grape, so further information regarding this phenomenon should be available in the future.

In addition to high color, Frontenac carries the riparia traits of high sugar and high acid. Soluble solids at harvest normally range from 24-28 °Brix, though measurements as high as 30 °Brix have been reported in some Minnesota vineyards. Since this sugar level is often coupled with titratable acidity (TA) ranging from 9-14 g/L (0.9-1.4%), winemakers may choose to ameliorate with water either before or after fermentation. This method can result in a lighter-bodied wine with less pronounced fruit characteristics. To emphasize the black cherry notes typical to Frontenac, some winemakers choose to stop fermentation before dryness, or sweeten the finished wine. The resulting residual sugar adds body and mouthfeel, enhances the perception of fruit in the finished wine, and reduces the perception of acid. Since palate balance is based on the equation

   Sweetness = Acidity + Bitterness

   (sugar)     (acid)     (tannins)

To many winemakers, the most frightening aspect of Frontenac is the high TA. At harvest, TA’s of 12.0 to 15.0 g/L are typical, though appropriate cluster thinning and canopy management techniques can result in significantly lower numbers. Though these numbers are initially daunting, harvest pH is generally low, ranging from 2.9 to 3.1. For this reason, malolactic fermentation is encouraged, and further deacidification with potassium bicarbonate is occasionally performed. At the research winery, standard practice to decrease acid includes inducing malolactic fermentation with a strong culture when the primary fermentation is almost, but not quite, finished. Since high acid may stress lactic acid bacteria (LAB) culture, other fermentation parameters are optimized as much as possible—MLF is induced in the primary fermenter without racking, for instance, and yeast lees are stirred thoroughly to re-suspended them in the wine at inoculation, providing nutrients for the LAB. The fermenter is kept as close to 70°F as possible, and LAB nutrient (not DAP) is used at a rate of 1.5 g/gal if MLF appears sluggish.

Once MLF is complete, the TA of the wine measured again, and wines that are still deemed to be too acidic are treated with a conservative amount of potassium bicarbonate. The wine is then put into cold stabilization, and TA checked in a couple weeks - if it's still high at that point, another small bicarbonate addition is made, with the total amount still kept below the 15g/gal recommended on the label. It’s important to note that bicarbonate additions are made incrementally, rather than all at once, to insure that the acid reduction can be fine-tuned to prevent excessive deacidification or production of off-flavors. Final acids higher than those acceptable in traditional wines can work well in Frontenac; because it is naturally low in tannin, the wine can support higher finished TA’s and still present a balanced palate structure. Lack of tannins makes acid the primary wine component giving Frontenac aging potential, so a TA of 9g/L or so is appropriate for reds meant for aging. Calcium carbonate additions for deacidification are generally not recommended, primarily because the off-notes produced are usually deemed unpleasant by consumer panels.

Both increased aging potential and improved flavor characteristics can be achieved through barrel aging or contact with oak chips or staves. Oak-derived aroma and flavor compounds can round out and soften the aggressive one-note cherry typical to Frontenac, producing a more complex wine suitable for consumption with heavier dishes. Enological tannins, which can be added before or after fermentation, are now widely available, but determining the correct rate of addition is a matter of trial and error. All tannin additions require extra aging to allow components to integrate; even so, many tannin-enhanced wines exhibit a disharmonious mouthfeel, where the tannins seem divorced from the rest of the palate, and the whole wine a bit clunky. As more tannin products are available and more winemakers experiment with them, this option may become more approachable, but the inexperienced should approach it with caution.

The final legacy of Frontenac’s riparia genetics is the occurrence in some wines of herbaceous notes, described as ‘tarry’ or ‘resinous.’ These are usually prominent when the vines have been overcropped, but in properly ripened fruit they should be very faint and just enhance complexity. Yeasts that claim to ‘enhance varietal character,’ however, should be avoided; they tend to enhance vegetative character as well. In fermentation trials performed at the Research Enology Lab, trained tasters preferred Frontenac reds produced with RC212, Pasteur Red, and BM 45, and L2226 yeast strains. Wines produced from Fermirouge and Barolo 97 were deemed to lack fruit and/or body.

As a general rule, aroma and flavor characteristics in Frontenac are dominated by a bold cherry note, with lesser hints of black current and general red fruit. Trained sensory panels have also identified notes of grass, green bean, evergreen, tar, and in some cases, chocolate.

Synopsis: Wine styles produced from Frontenac

Commercial production efforts hint at Frontenac’s flexibility in various styles. As mentioned above, rosé-style whites have been successfully produced from must allowed 0-8 hours skin contact time, and have proven popular in the commercial market. Though darker than traditional rosés, the wine color is jewel toned and strikingly deep, with no hint of tapering to an insipid salmon. Cool (55°F) fermentation with an aromatic yeast, like Cotes de Blancs, is recommended. The nose and palate showcase a bright, Bing cherry note that is enhanced by an off-dry finish and moderate acidity. Depending on the fruit, sugar levels from bone dry to moderately sweet have shown appropriate balance and customer acceptance.

As a red wine, Frontenac shows a deep garnet color, sometimes tinted with purple. Cherry notes predominate, but are typical of black or sweet cherry rather than the brighter note of the rosé. Earthy and slightly herbaceous notes round the palate, supported by a moderate acid backbone. Two to five days of skin contact produce optimum color, and some producers advocate producing separate lots of wine (a 2 day and a 7 day, for instance) and blending prior to cold stabilization to increase complexity. Barrel aging adds welcome structure and a synergistic hint of vanilla. While not as complex as a hearty vinifera, Frontenac packs a solid punch, and stands up well to heavier dishes.

A few creative producers have used Frontenac to produce port-style wines of outstanding quality. In port production, fermentation is stopped through the addition of grape neutral spirits while sugar content is still high, resulting in a product with higher sugar and 15-20% alcohol. The higher acid levels balance the increased sugar beautifully, deepening the typical fruit notes into lush shades of cherry, raspberry, black current, and stewed fruits. Some Frontenac ports exhibit pronounced chocolate notes, which seems dependent on vineyard microclimate. This dessert wine is a showstopper; a Frontenac port won a consensus gold at the 2004 and 2005 Indy Wine Festival. It wouldn’t be surprising to see an increase in commercial production in the coming seasons.

Wine Growers www.littlefatwino.com