Rehydrate

~According to my dictionary, “amelioration” is defined, “to make better,” or “to improve.”
~When I got into the Finger Lakes wine business in the nineteen eighties, I discovered that in Federal government regulations, amelioration was a function that took place in the winery, namely, adding water to juice, mostly to lower acidity, which is usually high in grapes grown in cool climate regions.
~The concept of amelioration was a joke to Farm Winery owners. We claimed the upper road of purity by having never even considered adding water to juice to make wine; that was a function of the big wine factories!
~To lower acidity, we could add calcium or potassium carbonate or we could induce malolactic fermentation.

Another avenue open to us was to not lower acidity but to add sugar before fermentation so that we could stop the fermentation before the yeast consumed all the sugar and still have wine with reasonable alcohol levels.

The added sugar would offset the acidity on the palate.

~Twenty-plus years later, lowering acidity in cool climate wine regions is handled just about the same way as it was before, but adding water to juice has become almost common practice in warm climate wine regions.
~Wait a minute: warm regions produce grapes lower in acid than in cool regions. Why would you need to add water to lower acidity?
~You don’t need to add water to juice to lower acidity in warm regions.

Ask a warm region winemaker about the procedure and the first thing you might be told is that water is not added to the juice—the juice is being rehydrated. In other words, water is being put back into the juice.

"Well, ok," you might ask, "why did you take the water out in the first place?”

You would be forgiven for asking because this is no easy topic, and I assume that my explanation is likely to be wrong in many places, but I’ll give it a shot.

The winemakers who read this blog can comment on my mistakes and maybe enlighten all of us.

~In warmer grape growing regions it’s not uncommon for grapes to reach high sugar levels quicker than they reach full maturity. That’s because grape maturity and high sugar levels are not exactly the same thing.
~The grape’s sugar, acid, and pH rise and fall based both on climatic conditions and on the fruit’s general growth cycle—while that is an issue both important and problematic to wine, it is not an issue solely of maturity.
~Grape maturity is reached when the recognized overall character of the fruit hits optimum expression, which is different for each grape variety and for each vineyard site. Maturity is expressed mainly through phenolic development and concentration, especially in the most aromatic white grapes and in just about all red grapes.
~Because of the inexact relationship between sugar development and maturity, it is almost a given in warm climates that sugar rises faster than the grapes mature. When that happens, rehydration is the fix.

Brix is the word used to express the measure of sugar solids in grape juice. The Brix at which grapes are picked indicate the potential alcohol of the finished wine.

The general ratio is that every 1 Brix degree fermented equals approximately .55 percent of alcohol by volume in the finished wine.

A dry wine at 12% alcohol by volume must have started out as juice at about 22 Brix (some sugar just about always remains after fermentation, as yeast have a hard time getting all of it as they age and grow weaker and die off during fermentation).

Put simply: the higher the Brix at the start of fermentation, the higher the alcohol of a dry wine in the end.

~If sugars rise before grape maturity, it’s conceivable in warm climates to pick mature grapes at extremely high Brix levels: 29 Brix at picking can potentially give you a wine above 15% alcohol.
~For grapes to reach 29 Brix it has to be warm and dry in that vineyard. That means often enough that the grapes have started to shrivel or take on the look of raisins as the fruit dehydrates.
~Winemakers faced with fruit in that condition add water to lower the Brix, which in turn lowers the potential alcohol after fermentation completes. They claim that their procedure does not affect the characteristics of maturity because they limit the extent of rehydration. Many strive for a reduction that takes alcohol down by no more than 1%, which would still leave a 15% wine at a high 14% (many winemakers claim grapes coming in at 30 Brix, which would interpret into higher than 15% alcohol after rehydration).
~To complicate the matter, there are the acids and pH issues.

Low acid/high pH wines are unstable mainly because they have lost some of their protective devices against microbial attack.

Grapes with high tannin, plus additions of sulfur dioxide offset some of the danger, but at certain reduced acid and high pH levels, it might take more to stabilize the wine.

Quite often, rehydration means adding water that has been acidified, to maintain a decent acidity level in the wine.

Acidified water calculations are tricky, since the winemaker is dealing with statistics based on liquid that will end up being reduced once again, this time by the removal of solids during fermentation and pressing.

~As you might expect, the issue of rehydration has its critics.
~First, there are the grape growers. Some claim that wine producers force them to leave grapes on the vines longer than necessary, and since their grape price contracts are tied to tonnage, the “raisining” of the grapes interprets into weight loss, robbing them of income. (They are particularly vexed when wineries add back the water, and weight).
~Second, there are the consumers who dislike high alcohol wines. They argue that leaving grapes to hang is a wine style issue, and that high alcohol wines with so-called concentration are produced mainly to gain critical acclaim as this is the style of wine that seems to please the palates of powerful wine critics.
~Third, there are those, like me, who cannot get past the idea of adding water to make wine.

Rehydration Ripeness

Copyright, Thomas Pellechia
November 2007. All Rights Reserved.