Paul,
If I’m understanding correctly, you are asking why it is that it is recommended to wait 4-6 weeks from the time you make a tannin addition until the time we bottle?
To answer this, I’m going to try to get a bit deeper into the whole tannin discussion and explain tannins without too much, scientific terminology, this is a generalization:
Tannins are large molecules made up of linked sub units, the chemical make-up of the tannins is actually changed during the winemaking process, creating chains, the chains then break, not only does the chain length change, but the different chemical entities that stick to the phenolic sub units (a class of chemical compounds consisting of a hydroxyl group bonded directly to an aromatic hydrocarbon group.) also changes.
The bonds between tannin polymers are repeatedly breaking and reforming.
This is a complex, dynamic process, the various phenolic subunits of tannins are sticking to each other and other chemical components of the wine in a sequential pattern, with these bonds being broken and reformed in a temporal sequence.
To summarize, the process of converting a monomer or a mixture of monomers into a polymer is called polymerization.
So, to answer your question, we bulk age for the following reasons.
- To allow full reaction and polymerization.
- Some Red wines need over a year of carboy or barrel aging to mellow out the harsh tannins.
- Over time tannins get bigger, become insoluble, and fall out of solution, this will be seen as sediment in bottles if you decide to bottle age versus bulk aging.
- When adding tannins, anyone that has used tannins will agree that tannin in general do not dilute easily, another concern of mine would be the fact that individual bottles may not have the same level of tannins.
- One of the more important reasons to bulk age would be the ability to taste the wine and make additions that may be needed, once the wine is in the bottle and corked, it makes it difficult to make adjustments.
I hope that this helps.