Wine 101: Tannin

[Rebel Rose]

Wine 101: Tannin

Wine is such a mysterious beverage. We sniff it, quaff it, swizzle it, and then come up with all these wild descriptors: cassis, meadow, leather, mushroom. Where do all these elusive aromas and flavors come from? Partly from the grape, partly from aging in oak, (partly from our imaginations), and partly from tannin.

Tannins are a group of chemicals that occur in the bark of many trees, cinnamon is an example, and in fruits, including grapes. Tannins are also present in black tea, and cause the astringent, drying effect that you experience after several cups of strong tea. You'll also notice a dry, sandpapery effect in your mouth after eating a whole bunch of table grapes. The tannins in grapes are a woody substance in the skin and seeds.

The pulp of a grape is mostly juice, as you can see if you slice a grape open. This is why wine grapes are generally small and round. Table grapes seem to get larger, longer, and more seedless every year (and in my opinion, a little more tasteless). Wine grapes, unattended in rich soil, can also become quite large. I have seen bunches of zinfandel grapes as long as my forearm and as heavy as a small salmon. But this is exactly what winemakers do not want. Smaller grapes have a higher skin-to-juice ratio, resulting in wines with color, flavor and tannin.

Some grapes, like Syrah, Nebbiolo and Cabernet Sauvignon have naturally higher levels of tannin than other grapes. Winemaking styles also preserve or delete some of the tannins in wine.

Tannins, which are insignificant in white wines, quite strong in young reds, and softened in older red wines, have a drying effect on the palate. Sometimes wine tasters claim that a completely dry wine tastes "sweet" to them. What they may be tasting, however, is a dry, fruity wine that has very little of the drying astringency contributed by young tannins.

Tannins are derived from flavanoids by condensing together catechin and proanthocyanidins. Catechin, a natural compound used in tanning hides, is also making press in health reports these days as one of nature's compounds responsible for maintaining a healthy heart. Proanthocyanidins simply mean pro (from), cyan (blue), antho (plants); meaning a complex of substances derived from blue fruits like grapes and plums.

White wines are made without much contact between the juice and skins. Without the blue pigments and flavors of red grapes, the skins of white grapes are simply bitter, and are discarded early in the winemaking process. Woody flavors in white wines are generally contributed by oak. Red wines, however, are allowed to ferment for up to ten days with their skins and seeds, sometimes stems as well. In fact, as the skins and seeds float to the top, winemakers and cellarmen make an effort to punch them back down into the wine several times a day; much the same as stirring a slow-cooking pasta sauce.

Tannins play an important role in the aging of wine, particularly red wine, and need careful mastery during wine-making as they can taste bitter and astringent if the fruit is squeezed too hard in the press, or if the skins are left in the juice too long. Handling the skins and seeds during winemaking is one of the most critical steps in optimizing the quality and character of red wine.

Tannins in wine come from both the grapes, and the wood in which it was aged. However, the tannin in wood differs in significant ways from grape tannins. And since wine barrels hold fifty-five gallons or more of wine, the ratio of wine to wood is less and the effect gentler.

Over time, as wines mature in the barrel, and particularly as they age in the bottle, tannins are removed. The tannin molecules agglomerate and polymerize, chaining together to form larger, more complex substances, so that eventually those molecules above a certain size precipitate as sediment and no longer have any bitter or astringent effect on the palate.

Medium-sized polymerized tannins interact with the proteins of taste buds sensitive to bitterness, while larger ones function as tanning agents and a natural preservative. This is why well-made red wines can age for years, while white wines should generally be drunk young.

This is also why it's difficult to properly taste white wines after drinking red wines. The drying effect of tannin results in what we call "palate fatigue." I generally suggest to wine tasters that instead of tasting the entire gamut of white and red wines at several wineries, that they set up a wine "quest" for the weekend, and only taste whites or reds, but not both.

It's also possible, if you are confused about whether you like wines that are sweetish or completely dry, that you prefer a certain level of tannin and oak. There are many levels of tannin structure in wines, in addition to the varying elusive flavors of the grapes. The next time you go wine tasting or buy a new brand of wine, take your time and study its aroma, its flavors, and that leathery, woody, seedy component called tannin.

[Behemoth]

DoverCanyon, thanks so much for writing up all this information. I am really just starting out in terms of getting serious about what I drink, and tannins have been a topic I have found confounding. When I read wine reviews, "tannic" seems to be a negative property, the opposite of "fruity", say. But fruity oaky (not sweet mind you) wines I don't like all that much, whereas, while I don't like to pucker when I drink, I do kind of like at least some tannin in there. I gather there is supposed to be a balance of the two -- but how much of one? Is there an industry standard or rule of thumb to these things? Or do I just have lousy taste in wine? Or maybe I need to be spending more to really see the fruity oaky stuff done right? (I tend to spend in the $10-$20 range, sometimes a little more, from a store with enthusiastic owners, and I'd rather stay in this range until I know what I'm doing).

[Rebel Rose]

Is there an industry standard or rule of thumb to these things?

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Wines should indeed be balanced, but everyone's palate is sensitive to different characteristics. All you need is confidence in your own taste. Understanding the concept of tannins, however, will help you understand why you might like some wines more than others. And I'm sure there are some excellent wines with tannic backbone in the 'Eminently Drinkable Plonk' thread!

A few years ago, I was writing back labels for Norman Vineyard, and Art Norman gave me a bottle of his (then $12) No Nonsense Red. It was made from barrel 'leftovers' of his estate Cabernet and Zinfandel, and a neighbor's Cab Franc. I had a glass while I prepped my dinner, another glass while I cooked dinner, a glass with dinner . . . it was tannic, but so yummy I polished off the bottle all by myself, and in the morning I couldn't remember a durn thing. Talk about 'creative writing.'

[KatieLoeb]

To "train" oneself to recognize tannin and it's effect on your taste and your mouth, oversteep some tea and let it sit out at room temperature for several hours. Then taste it. That "leathery, woody, seedy" thing that DoverCanyon speaks of will be forever etched in your mind and on your palate. The astringent effect on your palate will be very clear. When training staff, I speak about the "drag factor" of your tongue against the roof of your mouth. The higher the "drag quotient" the more tannic the wine is. When your saliva is in it's usual state your tongue will slide across the roof of your mouth easily since your saliva is slick. When drinking tannic substances, your tongue will skip or "drag" across the roof of your mouth as your saliva is denatured into those nasty strings that you see in the spit buckets at wine tastings. :retch: That drying and puckering sensation that's a bit different than an acidic one (like sucking a lemon) is what the tannins do.

The upside to all this is that tannins and fats counterbalance one another, so a big paint stripping tannic red wine with a honking slab of glistening juicy steak is a beautiful thing.

[Behemoth]

To "train" oneself to recognize tannin and it's effect on your taste and your mouth, oversteep some tea and let it sit out at room temperature for several hours.

I tend to forget and leave my beverages lying around (absentminded nerd) so I often drink my black tea at room temp. I may be a little too familiar with what tannins are.

The upside to all this is that tannins and fats counterbalance one another

Exactly what I like about them. I think wine acts the way bitter greens act in some cuisines, it cuts through the grease and makes you want to eat more. I doubt I could get through my SIL's wonderful christmas venison without the cabarnet chaser -- it's just too rich otherwise.

[turophile]

[Rebel Rose]

Where does the dryness come from then? Is it just a lack of residual sugars or is it from somewhere else?

You are correct in that there are two different types of 'dryness' in a wine. The first is a lack of residual sugar. However, a wine can be techically dry and yet still so exuberantly fruity that it might give a perception of sweetness, simply because people associate it with summer fruits or fruit salad.

The second experience of dryness comes from the tannins, as Katie pointed out. The extra astringency of the tannins add to the 'dryness' effect.

As an example, yesterday I had a couple in the tasting room who wanted to bounce around the tasting list. They ended up with our Bordeaux blend at the same time. The gentleman came to it after three white wines, and remarked that it was dry and very tannic. His companion tried it after the syrah, and she thought it was deeply fruity, like cherry skins, plums, and cinnamon.

[doviakw]

I don't know if this is the right place for this (I did search the Wine Forum for an appropriate thread) but ...

I have read a number of tasting notes that refer to a wine as having "sweet tannins". Now, I am a novice at this but I have never encountered a wine with noticeable tannin where I would describe the tannins as "sweet". I have found sweetness from residual sugar (port, etc.) or perceived sweetness from fruitiness (zinfandel) but I have never found tannins to be sweet (I think that I get "grippy" and "firm").

Could "sweet tannins" be equated with "not too much tannin" or "integrated tannins"? Perhaps I just need to taste more wine ... such a fate!

[if this is the wrong place for this question, please let me know and I'll search harder!]

[Rebel Rose]

Actually, I agree with you that I have never truly experienced "sweet" tannins, although I frequently see a wine described that way. I believe it to be marketing-speak for the soft tannins imparted particularly from oak. Depending on the type of oak used, barrel aging can sometimes give wine a dusky sweetness that is not really related to the experience of sugar, but is more a smoothing of the mouthfeel and a melding of fruit and wood components.

[Rebel Rose]

Barrel broker Mel Knox offered these observations by PM:

Mary: We should always remember that there are words and expressions we use when we are selling wine, and there are words and expressions we use when we are talking scientifically about wine.

The expression 'sweet tannins' is the in the first group.

I suppose that the person using these words might be trying to say

a)the wine was aged in barrels that were heavily toasted

b) the wine was aged in barrels made of staves that were air dried 2+ years

c)the grapes were allowed to ripen to the point where the grape tannins were not harsh

d)the winemaking created conditions where the tannins could polymerize

e)the tannins are covered with alcohol (which gives a sweet impression)

f)some combination of the above

I hope this helps...

[JohnL]

DoverCanyon, thanks so much for writing up all this information. I am really just starting out in terms of getting serious about what I drink, and tannins have been a topic I have found confounding. When I read wine reviews, "tannic" seems to be a negative property, the opposite of "fruity", say. But fruity oaky (not sweet mind you) wines I don't like all that much, whereas, while I don't like to pucker when I drink, I do kind of like at least some tannin in there. I gather there is supposed to be a balance of the two -- but how much of one? Is there an industry standard or rule of thumb to these things? Or do I just have lousy taste in wine? Or maybe I need to be spending more to really see the fruity oaky stuff done right? (I tend to spend in the $10-$20 range, sometimes a little more, from a store with enthusiastic owners, and I'd rather stay in this range until I know what I'm doing).

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Curious, what reviews are treating tannin as a "negative property"?

Also--

I would say that tannins are "felt" more than tasted. In other words more a sensation--astringency-- than an actual "flavor."

[JohnL]

Actually, I agree with you that I have never truly experienced "sweet" tannins, although I frequently see a wine described that way.  I believe it to be marketing-speak for the soft tannins imparted particularly from oak.  Depending on the type of oak used, barrel aging can sometimes give wine a dusky sweetness that is not really related to the experience of sugar, but is more a smoothing of the mouthfeel and a melding of fruit and wood components.

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Tannins can be fine or coarse grained--the impression on one's palate.

They can also be green hard, bitter and unripe or soft, ripe, round, sweet. this has to do with the overall physiological ripeness of the grapes ( fruit, skins and pips et al).

Wood aging has a definite impact all its own on a wine's tannins as do vinification techniques. Microbullage, racking, fining, filtration etc

The Australians have developed a "mouth feel wheel" that covers the sensations that one feels from wine. (i have one somewhere.

Anyway--as with most wine related issues this is complicated and often vague!

For the average drinker, I would recommend focusing on a wines flavors. If the astringency gets in the way of that, then put the wine in the cellar for a few years or move on to a "softer" less tannic wine.