nasty phenolic effect.
I waited for you guys to say something, before writing this lot.
My understanding of phenols is that we would not be able to detect the aroma of a ripening fruit without those lovely phenols. As the skin tightens around a swelling and ripening fruit, an organic reaction occurs, between the dermis of the fruit and the outer skin, that offers protection. The phenols are responsible for producing the fragrance, the aromatic oils require phenols to project the aroma into the air around our nose. Squeeze some fresh basic between your fingers and an amazing organic reaction occurs. Ok, basil is pungent, yet on a cold day it is not that noticable, the leaves are more stable, and there is no changing pressure going on inside the cells of the leaf.
For Pith, I think this is easier. Take a fresh sweet chestnut, that is not baked in the ashes, peel the hard brown skin layer off, and the soft creamy casing around the seed (nut) is the strongest flavour of pith I know.
With citrus fruits, pith is immediately under the skin and pigment layer, there is also pith between the segments of the fruit, yet as it ripens the pith is reduced in flavour and volume. The strongest pith flavour in a citrus fruit, is the protection immediately around the seeds in the central part of the fruit.
In white wine, and particularly the charateristics of SB, more pith is tasted in the dry style when the fruit is picked just before it turns and starts to ferment a little from its own yeasts. Therefore we do not detect much pith, if any in botrytised semillon and SB grapes for Sauternes, nor in chenin blanc grapes for moelleux Vouvray.
For reds, I find that gamay will produce some pith flavour in the beaujolais wines, and pith is evident in bourgogne pinot and some Mercurey. I'll say now, that my experience is limited to French and NZ white wines. For gamay and mercurey pinot, I consider this pith flavour to be due to ripeness of the fruit, and some soil types in the vineyard.
I know that all sounds somewhat simplistic, rather than purely sensory, but that is how I see it. Simply.... the taste and feel (furry as well in the mouth, as sometimes sensed on the gums) of pith on the tongue's taste buds. The tongue receptors measure (sense) pith differently, I generally detect most of the pith after the main flavour of the fruit and after the tannins, but that is the how my receptors are engineered.
Other folks have different receptors
