Designation (also polymerization or polyreaction) for the chemical reaction in which monomers (individual parts), which are mostly unsaturated organic compounds, react under the influence of catalysts to form polymers (multiples). Put simply, small molecules join together to form large molecules. The polymers are thus interconnected, long molecular chains of monomers. A distinction is made between homo-polymerization, in which only one monomer is reacted, and co-polymerization, in which react various monomers. In viticulture one understands by polymerization the "caking" of microscopically smallest parts in the wine, which then precipitated become (sink to the ground).
There are reactions between acetaldehyde. anthocyanins (Dyes), oxygen and tannins, whereby not all substances are always involved. The reaction among anthocyanins is called copigmentation, In these processes, simple phenol molecules become complex tannins (tannins) and pigment polymers (dyes). The changes concerning colour. taste and durability are only partially explored. The formation of the pigment polymers already begins during the mashing. This process is continued during the fermentation, and especially in the bottle aging, The color change in a red wine during the aging from usually purple to reddish brown also occurs by conversion of anthocyanins to pigment polymers.
In winemaking, this process is supplemented by the addition of oenological tannins promoted. These are added at different times (mash fermentation, BSA, bottling). They are able, under certain conditions, to promote the polymerization of anthocyanins to more intensely colored, sulfur dioxide-stable color pigments. Pigment polymers stabilize the color, improve the taste by weakening the color astringent Effect and contribute to the durability. In the case of old wines, individual polymers eventually become so large that they precipitate out of the solution and turn out to be depot at the bottle bottom deposit.