### acid | phenol:

Tannin
* Some tannins are also powerful antioxidants.
* act as a preservative and so are particularly present in wines meant for long aging
  - palate cleansers when paired with foods high in proteins or oils
* also help to mature the wine
  - taste richer and softer if they're riper in the first place
* appears to lower the digestibility of the protein and starch.
* are a group of unrelated chemicals that give plants an astringent taste
  - very complex group of plant anti-nutritional compounds
  - also much of the reason that wines mellow or improve with age
* are also present in tea-leaves
  - wine stems and seeds and in the barrels used to age wines
  - wood, and sometimes find their way into the wine from barrel aging
  - analogous to the beams and girders supporting a house
  - big and matched in perfect proportion by the fruit
  - bitter tasting chemicals that can interfere with digestion
  - classified as ergastic substances, i.e., non-protoplasm materials found in cells
  - distributed in species throughout the plant kingdom
  - especially evident in red wines, and generally help red wines to age
  - extracted with an aqueous organic solvent
  - fine-grained
* are firm and acids abundant
  - on the finish
* are found also in the barks of trees
  - in leaf, bud, seed, root, and stem tissues
  - highly astringent and are therefore used in many health care products today
  - in the smoke when a cigarette is burned
  - light and thin
  - located mainly in the vacuoles or surface wax of the plants
  - natural compounds found in grape skins, seeds and stems, and in oak barrels
  - overwhelming when cooked unripe as a mellow-yellow
  - phenolic compounds that precipitate proteins
  - plant products that inhibit digestion in livestock
  - probably responsible for bilberry's effect on diarrhea and wound healing
  - quite soft and the style of winemaking favours early drinking
  - responsible for the stringent flavor in the vinegar
  - ripe and sweet
  - smooth and integrated
* are soft and approachable
  - rounded
  - yet drying, almost bitter
  - sufficient to stand up to food and to provide a pleasant grip
  - supple and round
  - the astringent compounds in grape skins
* are the chemicals in grapes that give wine structure, especially during aging
  - flavour compounds that contribute to a red wine's ageability
  - most abundant phenolic compound in brown bird-resistant sorghum
  - third prominent pigment
  - tough and very noticeable
* are very bitter, and are produced when the plant is stressed
  - common in the plant world
  - soft but show a mild stemmy note that is attractive
  - waste products of cell processes found in vacuoles and cell walls, giving brown colors
  - water-soluble flavonoid polymers produced by plants and stored in vacuoles
  - what allow red wines to improve with age
* are, for example, contained in black tea.
* associated with prisms occurs in tannin sacs in white pine and tamarac bark.
* belong to the phenolics class.
* bind liquids, absorb toxins, and soothe inflamed tissues
  - to protein and can make plants with high levels have an astringent dry mouth taste
* binds protein and makes it unavailable for the body.
* can also react with iron present in fasteners or nails
  - bind proteins tightly together
  - cause nausea and even vomiting in people with sensitive stomachs
  - impart a faintly yellowish to brown color to water which never settles out
  - protect proteins against degradation by rumen microbes
* cause brown shades in some species.
* cause the brown colors of some leaves
  - hues in leaves of some oaks and other trees in the autumn
* contribute to many aspects of our daily lives.
* dominate at the moment, with noticeable acidity.
* exhibit antimicrobial activity towards many types of fungi, bacteria, and yeasts.
* frequently exists in red wines or wood-aged white wines.
* get more noticeable in the glass.
* give a wine a bitter taste and an astringent mouth-feel.
* help bind stools and hold back bowel movements
  - to make wines more astringent or mouth puckering
* induce changes in morphology of several species of ruminal bacteria.
* inhibit enzymatic activity, thus possibly affecting protein digestion.
* is essential to the taste and flavor of the grapes as well as the wine
  - firm, slightly green
  - grudgingly water soluble
  - present in the leaves
  - sometimes low
* make bird-resistant sorghums undesirable as a feed or forage crop.
* negatively affect an animal's feed intake, feed digestibility, and efficiency of production.
* occur naturally in grapes and sometimes in the wood in which wine is stored.
* occurs naturally in the skins and seeds of grapes.
* often occur in green or immature fruits, the quantity decreasing as the fruit ripens.
* play an important role in cork formation, which explains their presence in bark.
* produce brown colors often seen in tea, chestnut bark, and in oak leaves in the fall.
* produces negative effects on sapling growth.
* react with proteins and contribute to haze formation.
* seem to be created to discourage animals from eating the plants.
* still abound, fruit, wood, alcohol and acidity - all in abundance.
* tend to bind starches while being digested.
* usually bind to both dietary and microbial protein.