You’ll read tasting notes that call tannins round, angular, bitter, green, young, ripe, sweet, soft.. pick an adjective I’m sure it has been stuck in front of the word tannin in a tasting note somewhere. Ok, well “polka-dottted” probably hasn’t been used, but there are a lot of marketing folk out there hungry to sell more wines, it’s only a matter of time. So what are tannins really and what does it have to do with wine?
Tannins are the compounds in tree bark, teas, fruits (including grapes) that are responsible for the tactile sensation that is astringency. Astringency means pucker. Hehe. Pucker. Anyway, that mouth drying sensation that comes from unripe fruits, over brewed tea and young red wines is called astringency. Tannins create this sensation. Sourness and bitterness are often used in description, but tannins do not have flavour. They create a tactile sensation that have nothing to do with your tongue’s flavour receptors. They cannot be smelled or tasted. You read that right – they cannot be smelled or tasted. I’m sure if you looked through my TNs you will find me saying something like “sweet tannins” or “bitter tannins”. I’m learning too!
Grapes have tannins in their skins, seeds and stems. Tannins are also present in many woods – particularly oak, chestnut, and birch – and other plants. I’m not going to get too far into the chemical stuff behind it, mainly because I would need to pull out some old high school textbooks, and some memories need a little more time in the cellar before real enjoyment is possible. OAC chemistry. *shudder* Suffice to say they are polyphenols – molecules with more than one phenol. As a result of their chemical structure, they tend to like to bind with proteins. This property is actually where the name “tannin” came from; tannic compounds are used in the process of tanning hides. Binding to the residual animal proteins, they precipitate and allow the tanner (tannee?) to get right down to the hide. I have always hoped I would find a way to work leather and spanking into this space. Don’t worry the spanking part is coming. Anyway, those protein-binding reactions are thought to be the cause of astringency. The tannins react with the proteins in your mouth, trying to bind with them!
Wines get their tannins a number of ways. The types of grapes (some varieties like nebbiolo, cabernet sauvignon, syrah or tannat are naturally higher in tannins), the way the grapes are pressed (whole bunch pressings will add more tannins from stems), maceration times (extended time can extract more tannins from the grape skins and seeds), and which barrels are used for aging (new barrels from porous woods will add tannins) all impact the amount and kinds of tannins in the bottle. Note that most white wines are tannin free – little or no skin contact tends to mean there are no tannins extracted. Sometimes, a winemaker will want to remove tannins from the final product. She/he can use the properties of these polyphenols to his/her advantage during the fining process, and use fining agents that include some form of protein which will encourage the tannins to react and particulate and filter those bad boys out.
Tannins are a part of the “structure” of a wine, much like acidity (see my “deep dive on acidity” last month). As such, it drastically impacts the overall experience of the wine. Wines that are lacking in tannins just seem to be missing something. Like having flat cola – all the flavours are there, but without the bubbles it really lacks personality. Wines with heavy tannins spank your palate (hehe told you the spanking was coming) and leave you struggling to get the flavour profiles, as you are busy trying to peel your tongue off of the roof of your mouth.
The chemical make up of tannins also preserve the structure and colour of wine. This is why wines that are built to age will seem overly tannic in their youth. The winemaker has purposely used techniques that extract more tannins in order to ensure when the bottle is opened 10, 20 or 30 years later there will still be structure. That’s not to say these wines can’t be enjoyed in their youth, but you have to be prepared to accept the tannins.
For the visceral experience of tannins, I’d suggest a few things. The least expensive is to brew some tea and leave it to steep for an extra long time and then drink some. You’ll get that drying sensation that is the tannins in the tea trying to steal proteins from the wall of your mouth. If you live near any fruit growers (I grew up on Georgian Bay in the heart of Ontario’s apple country) go pick a piece of fruit months before it’s ready and take a bite. You’ll get the idea. Or, if you’d like go pick up a wine made from nebbiolo – a really young barolo would do the trick. Pop and pour take a drink and you will definitely get a sense of tannins.
As for the plethora of descriptors associated with tannins. I am beginning to understand a little more – the way that different tannins react together with the other components in a wine can create a totally different experience. We don’t have any adjectives in the english language to adequately describe the experience of a slow buildup dryness, a sharp breath taking pucker, or a mouth filling dryness that starts when the wine touches your lips and finishes when the last hint of fruit is disappearing. Angular? I’m not sure I get it either, but it sounds cool. I’ll work on finding a way to call my next experience with tannins polka-dotted.