Everything about tannin, particularly in terms of the wide range of red wine grapes grown in Lodi

Tannin is a major sensory attribute of red wines. Like the important role acidity plays in all the variations of white wines, sparkling wines and rosés, the factor of tannin content varies among all the red wines of the world. 

Differentiations among red wines depend primarily upon the grape variety from which the wines are made; and since many red wines are, in fact, blends of different grapes (in the U.S. "varietal" wines can be labeled by a single grape variety if at least 75% of the wine consists of that grape), tannin levels can vary depending upon the virtually endless variations of red wine blends produced around the world.

Tannin molecules found in red wines such as this Lodi grown Nebbiolo drawn from a barrel

Technically, tannin is a class of biomolecule found primarily in seeds of grapes, but also in skins and, if included, stems. Since red wines derive their color from the pigments (i.e., anthocyanins, also important for extraction of flavonoids) in the skins of black skinned grapes, they are typically made by fermenting complete with skins and seeds; thereby extracting tannin which, together with pigments, are collectively referred to as phenolic content.

Although removal of stems (i.e., destemming) prior to red wine fermentation is standard practice around the world, many vintners also make the stylistic choice of fermenting black skinned grapes as whole clusters, either fully or partially; in which case, additional tannin is extracted from stems.

Mosaic over 2,000 years old depicting Dionysus, the Greek god of wine, with red wine grapes.

On the sensory level, the major impact of tannin is on the palate: The phenolic content of red wines is responsible for the astringent, or drying, feel common to red wines. It may also impart the dense, bitter sensations that can contribute to the textural quality of wines as well as the antioxidant properties enhancing a wine's ability to improve over time.

Wines of all colors or types, of course, are typically described in terms of "body," which is primarily indicative of the level of alcohol in a wine (or "alcohol by volume," i.e., ABV). Wines described as "full bodied"are typically finished higher than 13%—in California, Washington and many parts of the New World, wines in excess of 14%, 15%, even up to 16% ABV are not uncommon. Because tannin can add something of a dense or meaty feel to a wine, it can contribute even further to a sense of fullness, especially in high ABV red wines.

French oak barrels filled with aging old vine Zinfandel in Lodi's The Lucas Winery.

There is still one more factor that can contribute to the taste of tannin in a wine: Oak barrel aging, which can add a modicum of wood tannin to a wine. Oak barrels, of course, are also often used in white wine production, which is why many whites made from Chardonnay (a popular candidate for oak aging) tend to taste fuller bodied than whites fermented and finished strictly in stainless steel tanks—in the case of the latter, typical of most commercial Sauvignon Blanc, Pinot Grigio (a.k.a., Pinot Gris), Riesling, or (popular varietals in Lodi) Albariño, Picpoul Blanc or Vermentino, which are largely "unoaked."

Barrel aging, though, is more commonly associated with red wines, and it is typically the strongest red wines highest in tannin that see the most oak aging; or, more likely, aging in brand new barrels, which impart stronger tannin and oak flavors than barrels that are considered more "neutral" (i.e., used over a period of 3 to 6 vintages). The quality and desirability of high priced California Cabernet Sauvignons, for instance, are enhanced tremendously by aging in new barrels; whereas red wines meant to be more subtle or reflect nuances of terroir (i.e., "sense of place")—such as many Pinot Noirs, vineyard-designate labeled Zinfandels, and reds made from Syrah, Grenache or Cinsaut—are typically aged in neutral barrels.

Grenache grapes—often called "Lodi's Pinot Noir" because, similar to Pinot Noirs, Lodi grown Grenache produces a red wine of restrained or soft tannin levels and balancing acidity, allowing its varietal spice (i.e., black peppery) perfume to shine through.

So let's put this all together and talk about differentiations in related specific terms: All of the most popular varietal red wines sold on store shelves in America—namely Cabernet Sauvignon, Merlot, Pinot Noir, Zinfandel, Syrah, Malbec and Petite Sirah—are typically full in body and enhanced by varying degrees of tannin. Although red wines made from grapes such as Pinot noir, Grenache or Cinsaut can be just as high in alcohol as a Cabernet Sauvignonl, they often taste lighter or softer in body simply because they are usually lower in tannin content than varietals such as Cabernet Sauvignon, Malbec or Merlot.

Therefore, if you prefer a red wine that comes across as softer or rounder in body—especially if you enjoy drinking red wines with, say, fish or salads—you should probably gravitate more towards lower tannin varietals such as Pinot Noir, Grenache or Cinsaut. If, on the other hand, you are a big meat eater and you prefer sturdier full bodied reds, you would naturally gravitate towards Cabernet Sauvignons, Malbecs, Merlots or Petite Sirahs.

Nebbiolo grapes in Lodi's Potrero Vineyard—owned and farmed by the Anaya family—which produces a red wine of sturdy tannin.

If, however, you prefer red wines with perceptible yet restrained levels of tannin—not too strong, not too soft—it might make sense to stick to varietals made from grapes known to impart moderate proportions of tannin, such as Zinfandel, Sangiovese (the major grape of Chianti in Italy's Tuscany region) or Tempranillo (the primary grape in Spain's Rioja and Ribera del Duero regions).

There is, of course, a lot more choices of red wines available from around the world; especially in an appellation such as Lodi, where a consistent Mediterranean climate and classic grape-friendly soils permit an unusually wide range of grape varieties to be grown productively.

That said, the following is a chart of major grape varieties—all of them (with the exception of Gamay) cultivated in the Lodi appellation—listed in the approximate order of their intrinsic levels of tannin, from highest to lowest:

Finally, there is one more factor often associated with red wines generous in tannin: Longevity, or possibility of aging in the bottle. The vast majority of wines purchased in the U.S., as it were, are consumed within hours of their purchase in a store. There are, though, many wine enthusiasts who love the taste of wines stored away for two, three, five or even more than ten years before opening. It is one of the many glories of wine appreciation, duly noted and celebrated since the rise and fall of the Roman Empire.

One of the biggest misconceptions, however, is that the higher the tannin in a wine, the most optimal its ability to improve after several years of "cellaring" (the latter word, used just as an expression—my own "cellar," for instance, are the hefty IKEA shelves sitting next to my couch in the living room). The fact of the matter is, tannin is far less a factor in the ageability of wines than qualities such as acidity and "balance" (the latter word, used to describe wines in which sensory components are ideally proportionate, with a sense of both intensity and restraint).

Example of high tannin/anthocyanin (color and flavonoids) red wine: Pure Lodi grown Petite Sirah.

Very recently, for example, a Master of Wine named Joel Butler pointed out on his Substack page (re his WineKnowLog© post, "What Wines are most age-worthy?") that perhaps the longest lived wines in the world are German Rieslings—white wines that have nary a speck of tannin; and, in fact, are typically very low in alcohol (8% to 10% ABV, 11% or 12% at the most). The finest German Rieslings can taste as fresh and perfectly balanced as practically the day they were born, even after 30 or 40 years. 

Other examples of wines that age well yet are either low or practically void of tannin include the reds (especially those made from Pinot noir) as well as white wines (Chardonnay) grown in Burgundy in France, which taste fantastic after 10 to 25 years in the bottle. As with German Rieslings, when it comes to Burgundian wines, it's all about balance and acidity, not tannin.

Zinfandel, such as this classic ancient vine (over 100 years old) bottling, is an example of a red wine with moderate tannin yet can remain fresh and zesty with acidity in the bottle even after aging over 10 years.

That said, however, generous proportions of tannin are very much a part of why red wines made from classic grapes such as Cabernet Sauvignon or Nebbiolo (the most important grape of Barolo and Barbaresco in Italy's Piedmont region) can mature very well indeed for anywhere between 10 to over 20 years. 

Still, tannin isn't everything. Grapes such as California Zinfandel, Sangiovese (from Italy or California) and Spain's Tempranillo (now a popular varietal in Lodi), for instance, are considered moderate tannin red wines, yet these wines have been known to age quite beautifully over 10 or 20 years. In Spain's Rioja region, the finest Tempranillo-based reds are bottled as "Gran Reserva," which see over 5 years of aging in wood and bottles even before they are released to the public—and invariably come out rapturous.

Harvesting of Lodi Tempranillo, a grape of medium-intense tannin sturdy enough to produce fairly long lived red wines by dint of depth of flavor and the variety's signature sense of balance (rather than sheer amount of tannin).

If, though, you love to collect and age wines for yourself, the following is Butler's short-and-sweet estimate of how long most (not all!) bottlings can age, according to grape and regional origins:

• Pinot Noir/Burgundy, 8-25 years.
• Syrah/Northern Rhône Valley, 8-30 years.
• Zinfandel, 6-20 years.
• Nebbiolo, 8-30 years.
• Riesling, 6-40 years.
• Chardonnay, 4-15 years
• Tempranillo, 7-25 years.
• California Cabernet Sauvignon, 8-20 years.
• Bordeaux crus, Similar to California Cabernet Sauvignon, 8-20 years. (Notes Butler on classic Bordeaux reds: "I don’t think we will see again wines like the 192’s, 1945s, or even those from the hot vintages of 1949 or 1982 which could continue unfolding for 40-60 years; but a minimum of 10 years old seems like a pretty solid bet.")

Cabernet Sauvignon—among the deepest tannin black skinned grapes in the world—growing alongside heirloom Flame Tokay grapes in Michael David Winery's Phillips Farms.