Astringency
The astringency (stress on the last syllable; from Latin astringere = to contract) describes the ability of a wine to cause a “rough”, “furry” mouthfeel in the wine language . Astringency is a trigeminal stimulus that is sometimes equated with a taste impression such as bitterness . It is created by a protein - tannin reaction, in which polyphenols such as tannins and other tannins react with the protein of the oral mucosa and precipitate the protein. In young red wines , astringency that varies depending on the grape variety and wine production is noticeable.
Excursus: wine
By storing the wine, it is ready to drink . This is done by polymerizing tannin molecules with anthocyanins (dye molecules) to form long-chain, non-astringent polymers. This process is promoted by oxygen , which is why wines with strong tannins are usually matured in small wooden barrels ( barriques ) with a large surface / volume ratio and correspondingly strong oxygen uptake (oxidative aging). If this is not enough, more oxygen can be added to the wine; this is the process of micro-oxygenation (MOX). However, the oxygen partial pressure must not be too high, otherwise oxidative spoilage of the wine occurs, or insufficiently long-chain polymers are formed, which in turn have an astringent effect.
For wines with strong tannins, for example from Cabernet Sauvignon , Tannat , Malbec , Syrah or Mourvèdre , a long-term bottle aging is necessary to further reduce the astringency. The oxygen in the gas space of the bottle is sufficient for this.
Another way to reduce astringency is fining , for example with egg white. The protein-tannin reaction takes place on the added protein, which is precipitated by the tannins present in the wine.
Sloe wine contains more tannins than high-tannin wines, even when properly harvested, produced and stored. In contrast to red wines, a clearly perceptible astringency is part of the character of sloe wine. It is therefore usually not perceived as annoying.
A substance that causes such an astringent , i.e. contracting feeling, is called an astringent .
Other mentions
This expression is also used when tasting chocolate, tea and olive oil.
In medicine, this is understood to mean substances that cause the skin to contract.
The cosmetics industry has recognized this effect and produces various products such as:
- Antiperspirants
- Facial toner
- Lotions
- Razor pencils
- Mouthwashes with aluminum chloride
literature
- Jancis Robinson : The Oxford Wine Lexicon . Hallwag, Gräfe and Unzer, Munich 2006, ISBN 978-3-8338-0691-9 .
- N. Schöbel et al .: Astringency is a trigeminal sensation that involves the activation of G protein-coupled signaling by phenolic compounds . In: Chemical Senses . 2014, doi : 10.1093 / chemse / bju014 .
Individual evidence
- ^ Fritz-Jürgen Nöhring: Specialized dictionary medicine - Fritz-Jürgen Nöhring . Elsevier, Urban & FischerVerlag, 2002, ISBN 3-437-15100-2 , pp. 109 ( limited preview in Google Book search).
- ↑ Niko Kaindl: Getting rid of acne and pimples: successful against blackheads, rosacea and ... BoD - Books on Demand, 2012, ISBN 3-8482-0829-6 , p. 68 ( limited preview in Google Book search).