Clark Smith

[mark meyer]

originally posted by Christian Miller (CMM):

originally posted by mark meyer:

Christian,

I think it is the concentration angle-here is what the Winemaking Tasmania website says about wine and juice concentration. They also have a bit on alc adjustment if you go to the website.

mark

The Memstar concentration process treats grape juice or wine to increase flavour intensity, colour and body. It does this by using reverse osmosis to remove a portion of the grape juice or wine as permeate. Grape juice concentration by reverse osmosis has been used for many years for the removal of water to increase sugar and flavour concentration.

It is ideal for treating juices and musts that have become heavily diluted as a result of rain just before harvest. It is a superior technique for alcohol augmentation compared with the addition of sugar (chaptalisation) but has limited benefits where the grapes are green and under-ripe. Wine concentration after fermentation is the preferred option when sugar levels are already high but the concentration of flavour, colour and other quality components is low.

Typically, you will notice a significant improvement in wine quality with the removal of 10% to 20% of the original volume as permeate. This is a simple, quick and reversible technique

My experience in tasting RO trials was strictly for removal of alchol, with the trials being done in quite small increments. Clark Smith has plenty more to say on this process. I can imagine how using it for concentration might be an improvement for rain-bloated grapes, and why it wouldn't work well with "under-ripe" grapes (a contentious topic in itself that I'll try to avoid here). I can't say the few tastings I've had of wines "augmented" with RO-created concentrate have impressed me, but maybe there's an art to it. I'm curious as to why you say it's superior to chaptalization for alcohol augmentation (independent of flavor and concentration issues).

Christian,

I emailed a winemaker in Tasmania who I discussed RO with-he is against using it. It appears it is used to reduce alcohol. I noticed on the Winemaking Tasmania website that they ensure confidentiality for those wishing to use RO.
Here is the relevent response on RO from the Tasmania winemaker.

This discussion is one of style and the means to creating that style. Of late judges and some wine makers have been directed to find very bright ripe to over ripe flavors in their pinots. As in any fruit grapes go through a spectrum of different flavors as sugar levels increase from green acidic flavors through to over cooked plums at it ripest. The intensity of flavor is not only related to sugar level but also cropping level. The more crop the thinner the flavor , the longer and the more energy it takes to ripen the fruit. The level of fruit on the vine relates to vigor of sight and age of vines. The younger the vine , the greater the cropping level.

Tasmania for the most part due to our high rain fall and number of sunny days has relativley high vigor ( this is not always the case) and our vines relative to say the Barossa are comparativley young so we expect to carry fairly high crops. The cool temperatures give us high fruit intensity as a result of a longer growing season, but it often takes much higher sugar levels to get into the plumb end of the spectrum. So by removing some of the alcohol, bringing it back from 15% to 13,4 % you loose the alcoholic heat which would otherwise take the wine out of balance.

mark