Tannin

Tannins are a heterogeneous group of high-molecular-weight polyphenols that precipitate proteins, cause astringency, and contribute to the structure and mouthfeel of wine, tea, and many botanical beverages. They are divided into hydrolyzable tannins (found in oak) and condensed tannins (proanthocyanidins, found in grape seeds and skins).

The word 'tannin' derives from the use of these compounds in leather tanning — they bind and precipitate collagen proteins in hides, converting them to stable leather. The same protein-binding property produces the characteristic drying, puckering sensation in the mouth when astringent foods and drinks are consumed: tannins bind proline-rich salivary proteins, reducing lubrication and creating the friction-like sensation of astringency.

In wine, condensed tannins (proanthocyanidins) from grape skins and seeds are central to the structure of red wines. They contribute to the wine's ability to age, as tannin polymerization over time produces softer, more complex phenolic structures. In dealcoholized red wine, the tannin content is largely preserved — these high-molecular-weight compounds do not pass through RO membranes or evaporate during vacuum distillation. Dealcoholized red wine can therefore be genuinely tannic, providing the structural experience red wine drinkers expect.

For zero-proof spirit production, botanical tannins contribute an important dimension of complexity and perceived 'depth.' Ingredients like oak bark, black walnut, rooibos, and grape seed extract are used to build a tannin scaffold in zero-proof spirits that creates the impression of maturity and weight. Managing tannin levels is critical, however: excess tannins produce harsh, drying bitterness that overwhelms other flavor components.

A winemaking note relevant to zero-proof wine producers: the concept of 'tannin management' has become highly sophisticated in modern winemaking, with producers choosing specific extraction techniques (pump-overs, punch-downs, micro-oxygenation) to achieve target tannin quality and quantity. The same intentional approach to tannin management applies equally to zero-proof wine production, where the tannin profile of the dealcoholized product can be adjusted through grape selection, maceration protocols, and post-dealcoholization tannin addition.