Why is there residue in the empty bottle of wine?
When wine is made, it starts out with quite a bit of solids in it – grapes, yeast, and so on. Sugar and later alcohol dissolve in water (which is of course the major component of the grape juice) but many of the rest of the raw ingredients don’t. As the wine ferments, most of these solids sink to the bottom, and when the wine is decanted into bottles, this sediment gets left behind. However, some of the solids are in very small particles which end up in suspension in the wine (not dissolved, but in such small particles that they are too light for gravity to make them sink to the bottom unless left undisturbed for a very long time). As the wine is fermenting, there is so much of this that the wine is actually cloudy, and there are various techniques employed at the end of fermentation to clarify the wine. Sometimes of course, this process does not work perfectly, and some particles are left in the wine. If the wine is then left undisturbed, it will sink to the bottom of the bottle and f
