Phenolic content in wine the ellagic and gallic acid found in the wood. In the vineyards, there is also a growing distinction being made between "ripe" and "unripe" tannins present in the grape. This "physiological ripeness", which is roughly determined by tasting the grapes off the vines, is being used along with sugar levels as a determination of when to harvest. The idea is that "riper" tannins will taste softer but still impart some of the texture components found favorable in wine. In winemaking, the amount of the time that the must spends in contact with the grape skins, stems and seeds will influence
Seibel grapes or two of Albert Seibel’s grapes together and name their creations after themselves, e.g., Seyve-Villard 5276 (“Seyval Blanc”). Seibel grapes Seibel grapes are a group of wine grape varieties which originated with the work of Albert Seibel crossing European grape with American grape species to increase disease resistance. They were planted widely in France during the 1950s but have seen decline in recent years because French wine law proscribes hybrid grapes in appellation wine. The grapes are still commonly used as blending grapes in table wine and mass commercial wines. New Zealand, England, and Canada also have plantings of Seibel