Thanks for the welcome eyedoc. Viticulture does seem to play an important role in making great wine. I was reading some history on the subject (can't seem to find the source at the moment) and what is baffling is that winemaking and viticulture hasn't always been as tightly integrated as they are now. To me, this really seems to tie into the contribution of making a better wine, hence the question. So I would assume that one of the advancements is the integration of the two, and I am sure there are other advancements that contribute as well.
I agree with your assessment of the integration of the two. Other advancements are those such as Velcorin, juice concentrators, reverse osmosis, alcohol reduction, the ability to remove Brett characters from wine as well as TCA/off moldy and musty characters amongst others.
Now I've heard the term reverse osmosis before, but could you explain (at a very high level in layman's terms) what the heck it is? It sort of sounds like a filtering process; if so, what's eliminated when the process is complete?
Reverse osmosis involves Reverse osmosis (RO) is a separation process that uses pressure to force a solution through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side. More formally, it is the process of forcing a solvent from a region of high solute concentration through a membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration when no external pressure is applied. The membrane here is semipermeable, meaning it allows the passage of solvent but not of solute.
The membranes used for reverse osmosis have a dense barrier layer in the polymer matrix where most separation occurs. In most cases the membrane is designed to allow only water to pass through this dense layer while preventing the passage of solutes (such as salt ions). This process requires that a high pressure be exerted on the high concentration side of the membrane, usually 2?17 bar (30?250 psi) for fresh and brackish water, and 40?70 bar (600?1000 psi) for seawater, which has around 24 bar (350 psi) natural osmotic pressure which must be overcome.
This process is best known for its use in desalination (removing the salt from sea water to get fresh water), but it has also been used to purify fresh water for medical, industrial and domestic applications since the early 1970s.
When two solutions with different concentrations of a solute are mixed, the total amount of solutes in the two solutions will be equally distributed in the total amount of solvent from the two solution.
Instead of mixing the two solutions together, they can be put in two compartments where they are separated from each other by a semipermeable membrane. The semipermeable membrane does not allow the solutes to move from one compartment to the other, but allows the solvent to move. Since equilibrium cannot be achieved by the movement of solutes from the compartment with high solute concentration to the one with low solute concentration, it is instead achieved by the movement of the solvent from areas of low solute concentration to areas of high solute concentration. When the solvent moves away from low concentration areas, it causes these areas to become more concentrated. On the other side, when the solvent moves into areas of high concentration, solute concentration will decrease. This process is termed osmosis. The tendency for solvent to flow through the membrane can be expressed as "osmotic pressure", since it is analogous to flow caused by a pressure differential.
In reverse osmosis, in a similar setup as that in osmosis, pressure is applied to the compartment with high concentration. In this case, there are two forces influencing the movement of water: the pressure caused by the difference in solute concentration between the two compartments (the osmotic pressure) and the externally applied pressure.
Reverse osmosis is used primarily for two purposes in winemaking; the removal of water and thus concentration of must and removal of alchohol.
