This is the pomace from red wine fermentation that is made up of the skins, seeds, stems of red wine.  once the juice has been pressed away from these solids, the pomace is sold off to goats farm as feed.

Unless you’ve won some contests involving watermelon seeds, you play pro baseball or you indulge in smokeless tobacco, spitting likely is not something you’re very good at. As a kid, I did my darndest to spit and to whistle with no success at either, much to the dismay of my male cousins.
We’ve all been well-trained—when you [...]