What Are Tannins?

What Are Tannins?

Tannins are an astringent compound found in plants that are responsible for the gritty texture in red wines. They have no flavor or aroma but can be experienced as dryness. The word tannin stems from the use of this compound to “tan” leather. Which is why your tongue feels a little like leather when drinking a high tannin wine without food. Wikipedia defines tannins as “an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids”. That is certainly a mouthfeel but the key points are that it is bitter and that it binds with proteins. Both of these characteristics is what leads to that dry taste red wines are known for. Where do Tannins Come From? Wines pick up tannins from the stems, seeds, and skins of winemaking grapes. White wines, as you know, do not undergo a long maceration (aging on the skins). Because of this they have little in the way of tannins and they don’t pick up the coloring of the skins. Red wine must on the other hand is fermented an let to sit with the skins and seeds for some time in order to extract the maximum amount of flavor, aroma, and color. However, they pick up a lot of tannins along the way. Oak is another source of tannins. Red wines often being aged in oak can pick up still more tannins. You can see that the control of tannins is a concern when making red wines. Tannins may also be purchased in a powdered form and added to your wine if you find it lacking. Often this is done with wine kits which are low in tannins so that they become drinkable sooner (read this). Tannins and Protein As I mentioned earlier the fact that tannins interact with and precipitate proteins is a key point to understanding tannins. When tannins come into contact with proteins they bind together and sink to the bottom of whatever container they are in. This removes both the protein and the tannin from the wine. An excess of protein in wine can cause haziness. However, due to the presence of tannins during fermentation most of the protein is precipitate out. The biggest effect of this interaction comes when drinking red wines. Take a sip of red wine without any food and you’ll notice that your tongue feels dry and unprotected. This happens because the tannins in the wine bind with proteins in your saliva. When this happens your tongue is left “exposed” and feeling like you just licked a 2×4. It is this precipitating action that makes red wines go so well with high protein foods like steak and sharp cheeses. The tannins bind with the excess protein in your mouth and makes the wine much easier on your mouth. Not to mention how nicely the flavors of red wine and heavy proteins go together. Tannins and Time Have you ever wondered why red wines are aged for so long while whites normally aren’t? Well, a good part of the reason is the level of...

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The Anatomy of a Grape

The Anatomy of a Grape

Knowing and understanding grapes is absolutely essential to making good wine. After all these little berries are what it all starts with right? By their very nature grapes are the perfect winemaking fruit. No other fruit contains the perfect amounts of sugar, acidity, and phenolic compounds to create such an amazing beverage. Any other fruit requires additional sugar or other ingredients to even produce alcohol. Let’s get to know our little friend a little bit better. Shall we? Physical Components of the Grape The Skin At only six to ten cells thick you wouldn’t think there’s much to the skin of a grape. However, this membrane contains many key elements for red wines. Less so for white wines as the juice spends little time in contact with the skins. The outer surface of the skin is the cuticle, a wax like covering that waterproofs the berry. Protecting it from outside influences.¬†Within the thin skin are a ton of components including aromatic substances, potassium, and phenolic compounds. Phenolic compounds refer to a group of compounds, however, there are two very important ones that need to be explored. The first are anthocyanins. These are pigment compounds that give the grape its color and in turn gives red wine its color. As wine ages these anthocyanins combine with other phenolic compounds which serves to stabilize the color of the wine. The second phenolic compound of interest are tannins. Also present in the seeds tannins give wine an astringent and bitter taste. Tannins also combine over time and alter the taste and mouth feel of a wine. Red wines in particular get most of their flavor and spunk from the skins. Merely pressing red grapes and fermenting the juice results in what the French call “Blanc de Noir” meaning white wine from red grapes, or literally white from black. The Pulp The bulk of the grape is made up of the pulp beneath the skin. This is where the grape juice comes from.¬†Vacuoles contain the juice and when broken release the “free run” juice. As you can see in the diagram the pulp contains many compounds of its own including: sugar water aromas potassium tartaric acid malic acid In white wine making the pulp provides the bulk of the flavor and acidity. Red wines get their flavor first from the skins but also from the pulp. Seeds Moving inward we come to the seeds. These are large caches of tannins. So much so that as winemakers we must be careful not to crush the seeds during the pressing of the grapes. By crushing the seeds, and stray stems, the tannins are overdone. If this happens your wine will need much more time in the bottle to become palatable. Chemicals Within The Grape The chemical makeup of a grape is quite diverse and complex. We’ll just hit the major components here. Sugars The sugars within the grape are what the yeast consume to produce the alcohol in wine, as you already know. What we refer to as “sugar” in a grape is actually a combination of several different kinds of sugar. Primarily there is...

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