RO

Florida Jim

Florida Jim

Florida Jim
This past week I had an interesting experience.
In a side by side comparison (blind), I tried a glass of a 2009 cabernet sauvignon; one glass was the original juice (VA over 1.0) and one was the same juice run through RO with the water reduced by 25% (VA now about .8).
No attempt was made to reduce alcohol in this process; however some is extracted in almost the same proportion as water.
The initial juice did not smell volatile and it was fresher with more fruit. The RO juice had less fruit on the nose (possibly due to a lower VA) and was more about coffee than fruit in the mouth.
I found the RO juice a bit muddy but this process had only been done about a week prior and the sulphur level was higher in the RO juice.
I liked the original juice best at this time but hope I get a chance to follow both in barrel to see what changes their future holds.
‘Also got a chance to try the same test with a 2009 syrah.
I liked the RO juice best for its obvious increase in concentration and its satin textures. The aroma and flavor profiles were more similar among the syrah samples, but I would say the RO wine was the more expressive.
The RO process with this wine had been done at the same time as the cabernet noted above.
I remember some side by side tests that TomHill reported on several years ago. While I admit that the fact that I liked the RO syrah better is a bit disconcerting, like Tom (if I recall correctly), I was not displeased with the results.
I have no intention of using the process for my own wines but, as with most everything in wine, it’s instructive to taste.
Best, Jim
 
Interesting, thanks. I just finished reading Kramer's recent book, and he talks about RO and its effects in several essay, but without the careful detail of your description.
 
originally posted by Florida Jim:
No attempt was made to reduce alcohol in this process; however some is extracted in almost the same proportion as water.
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Most interesting, Jim. As with most tools, I suspect that the effect depends more on its usage rather than the tool itself. I have concerns about the above statement, though: water and alcohol evaporate together in a 5:95 ratio*, so if the loss of water is due to evaporation then alcohol should evaporate 19-fold faster instead of the equal proportion that you noted. If the alcohol is extracted in the same proportion as the water, it sounds like some deliberate attempt is being made to retain the alcohol.

Mark Lipton

* The technical term for this is an azeotrope.
 
Mark,
The technical aspects of the process are beyond me.
I was told that, in this case, if the wine started out at 14% it would end up at about 14.1%.
Whether that is the nature of the tool or the mechanic, I don't know.

Considering the wines involved here and the people who own them, I do not believe that any attempt was made to decrease alcohol nor would there ever be.
Best, Jim
 
originally posted by MLipton:
originally posted by Florida Jim:
No attempt was made to reduce alcohol in this process; however some is extracted in almost the same proportion as water.
Click to expand...

Most interesting, Jim. As with most tools, I suspect that the effect depends more on its usage rather than the tool itself. I have concerns about the above statement, though: water and alcohol evaporate together in a 5:95 ratio*, so if the loss of water is due to evaporation then alcohol should evaporate 19-fold faster instead of the equal proportion that you noted. If the alcohol is extracted in the same proportion as the water, it sounds like some deliberate attempt is being made to retain the alcohol.

Mark Lipton

* The technical term for this is an azeotrope.
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They just push through the membrane together, though, no?
 
originally posted by Oswaldo Costa:
Sure it´s a dumb question, but why is VA (volatile acidity?) a parameter?
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I don't know.
I assume that the process is used for VA removal and that, when concentrating (as was the case here) some is removed in the natural order of things.
(But as I say, I have no idea what the chemistry is)
Best, Jim
 
RO pushes the small stuff in wine (water, ethanol, acetic acid) through tiny holes in a membrane. Bigger stuff (most colored things, lots of flavor molecules but probably not all, tannin, etc.) stays behind.

You can distill the stuff that comes through and add things back if you like, too.
 
We just bought an RO filter to spoof out the tap water in our apartment. Not sure that it will provide many interesting tasting notes however.
 
originally posted by Rahsaan:
We just bought an RO filter to spoof out the tap water in our apartment. Not sure that it will provide many interesting tasting notes however.
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It tends to remove salts as well as other things, and can thus leave your water tasting a bit bland.

There are worse things than bland, of course.
 
originally posted by Ian Fitzsimmons:
originally posted by Rahsaan:
We just bought an RO filter to spoof out the tap water in our apartment. Not sure that it will provide many interesting tasting notes however.
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What's the energy cost?
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Nothing extra. It runs based on water pressure. It uses a bit more water to clean itself, although the company claims you won't notice it on your bill. We certainly won't because we live in an apartment and don't pay a water bill.
 
originally posted by SFJoe:

They just push through the membrane together, though, no?
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D'Oh! {sound of palm slapping forehead} My ignorance has come full circle: years ago, when I first learned of dealcoholization via RO I questioned how one could selectively partition EtOH through a membrane and was told about evaporation. Now I assume that all RO involves the evaporation of the filtrate... Go figger.

Jim: what they're doing makes perfect sense now that the scales have been lifted from my eyes. They're just concentrating the wine by removing the liquids and alcohol and water look about the same in that respect. So, yeah, 14% in, 14% out. Sorry for the cornfuzzlement.

Mark Lipton
 
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