January 31, 2011

A Fountain of Youth?

Égrappage *
Partial or complete removal of grape stalks prior to fermentation, usually by machine. Results in reduced tannins, making for softer, earlier maturing, fruitier red wines. Always done for white wines. Some stems may be left in to keep the ‘marc’ loose during pressing.
The long-held belief that all wine should be aged for long periods hearkens back to when winegrapes were pressed in whole bunches -- stems, seeds and all. The classic image of Oporto’s “black feet” stomping grapes doesn’t show that the stems are being stomped just as aggressively as the grapes. And the same with primitive pressing technology: the stems were included with the grape mash. Often the result was wines that had very high tannin content. In fact, many old style wines were so tannic that they were hard to tolerate until some of the tannins had softened from cellar ageing -- possibly for many years.

A fairly modern improvement in grape processing is the crusher/destemmer. This machine crushes the grape bunches to release the juice, and then strips away the stems, leaving fermentable juice that is relatively stem free. As a red wine macerates and ferments, it extracts tannin from the stems and skins, and from the pits to some degree (although these too are often removed). When the stems are removed before fermentation, the wines emerge less tannic, softer, and earlier maturing. A classic example is Brunello. Traditionally these wines took 10 to 20 years to soften to drinkability, but with more modern techniques -- including égrappage -- the wines can be ready to open well before their tenth birthday. (I have had Brunello as young as 5 years that was perfectly balanced and drinkable.)

Égrappage gives the winemaker another area of control over the wine: Remove all the stems for an early-drinking, fruit forward wine; leave in a small percentage of stems for added structure and longevity; or maximize stem content to create a traditional cellar monster. 

January 24, 2011

All That Sparkles

Diamonds/Gravel *

    Harmless tartrate crystals from tartaric acid that precipitate out of finished wine, especially when chilled. Can be a good sign, showing that the wine has not been over processed.

Acids are an important component of all wines. They provide structure (backbone), contribute to a wine’s impression of freshness, and help make wine food friendly. There are roughly a half dozen different acids to be found in wine, but tartaric acid is by far the most plentiful.

Winemakers put a lot of effort into managing acid, beginning in the vineyard where getting the sugar/acid balance just right is a primary goal. Depending on local rules, the winemaker may ‘adjust’ acid before starting fermentation. All through its stay at the winery, the wine’s acid will be monitored. One trick winemakers use to lower acidity is to ‘cold stabilize’ the wine prior to bottling. This entails refrigerating the wine to just above freezing for up to a week, which forces the tartaric acid to form crystals, softening the wine. (Incidentally, the crystals are later scraped from the tank and sold as a basic ingredient in baking powder.)

You may have seen these tartrate crystals in a bottle or glass, or on the cork. (These can look like bits of glass.) This actually is a good sign. It means the winemaker has not processed the dickens out of the wine and that it had ample acidity when bottled. Diamonds, like all sediment, is a good thing, although getting a mouthful of it is rather off-putting. If you see a lot of crystals in the bottle, pour very gently or -- better -- decant the wine off the sediment and enjoy!

January 17, 2011

A Vine Distinction

Clone *

    Winegrape vines are propagated from cuttings; therefore, each plant is a “clone” of its parent. Varieties can also mutate into a number of clonal variations over time. Most vineyards are planted with a selected variety of clones of the same grape.

There are an estimated 10,000 varieties of winegrape, with roughly 6,000 varieties currently used to make wine. Yet despite this wealth of choice, there are relatively few winegrapes in widespread use.

The winegrape vine is somewhat prone to mutation. One theory is that all grapevines (at least in Europe) are descended from a distant relative of the Muscat grape, which proliferated in the region of the Black Sea. Once humans decided to farm rather than roam, they began to cultivate. It was natural to save the seeds from the best examples to plant for next year. And as with carrots or wheat, this also applied to winegrapes. The grape’s propensity to mutate was both good news and bad news. A new version of the plant might create an even better wine than its parent plant. But if you can’t predict what the plant’s seed will produce, how do you recreate that special variety? The answer is to plant parts of the original plant rather than the seeds. In effect, you simply clone the desired plant.

There you have plant husbandry in a nutshell. Plant the sticks, not the seeds. That way you know that the resulting vine will produce exactly the same grapes as the parent plant ... mostly. There is still the issue of spontaneous mutation. That too has a silver lining. Take that interesting stick (mutations quite often show up as a single cane on a parent vine) and plant it. So when your pinot noir vine produces a cane filled with light blue grapes, plant that cane and call it “pinot gris”.

Sometimes a mutation will be almost the same as the original plant, but with some characteristic that is worth preserving. That cane, too, can be isolated and cloned. Pinot noir has an estimated 1000 clones, all of which produce a wine recognizable as pinot noir. In Ontario, winemakers are crazy about a clone called chardonnay musqué. The wine is chardonnay in every way, but it has a wonderful muscat element not found in typical chardonnays.
Part of the art and science of planting a vineyard is choosing which grapes and which clones of those grapes to plant. Often the vineyard will be planted with a few carefully selected clones of the basic vine, partly for some genetic diversity but more to achieve a certain type of wine.

January 10, 2011

A Stirring Tale


    The act of stirring the lees in vat or barrel. Helps avoid production of hydrogen sulphide and facilitates absorption of wood tannins and lees flavours
There are two schools of thought on stirring wine. One is to stir often; the other is to not stir at all. The decision to stir or not stir a ‘working’ wine will encourage the development of certain characteristics. In the case of a red wine, the wine will be vigorously manipulated during its first week or so of fermentation to keep the skins and grape solids in contact with the juice. A white wine might also be stirred during this primary stage of fermentation to help distribute the growing yeast cells and to make sure they are exposed to the nutrients in the juice. Some winemakers will stir a working wine up to three times a day.

Once fermentation has pretty much finished, stirring takes on a different mission. The majority of wines are racked into clean vessels and left alone to mature in peace. Some purists even insist that disturbing the wine during this stage can bruise it (whatever that means). If a wine is undergoing malolactic fermentation, which is frequently done with red wines and with chardonnay, then stirring the lees will help foster the malolactic bacteria and bring out the desired soft ‘sur lie’ quality.

Lees are dead yeast cells, and mixing them into the wine helps integrate toasty and biscuity qualities into the wine. You’ll find this character in sur lie chardonnay, vinho verde, and quality sparkling wines, especially champagne. Sometimes the wine is bottled directly from the barrel, in which case the label may say “Bottled on lees”or “Unfiltered” and the wine may show a trace of fine sediment. The resulting wines generally show more character than those that have not undergone lee stirring.

January 3, 2011

The Trouble with Angel’s

Angel’s Share
    A quaint term that refers to the wine that goes missing from the barrel during ageing. Real world cause is evaporation through the pores and seams of the barrel. Can amount to a loss of 5% or more over a year of barrel ageing, which must be periodically topped up. Contributes to a wine’s concentration
For centuries, winemakers have turned to wooden barrels for the final ageing of their best wines. Usually made from oak, wine barrels are held together with nothing more than a few reinforcing rings -- no glue, no nails. Even the heads are sealed with simple strips of bulrush. The result is a barrel that is water-tight and very nearly air-tight. And it’s that “very nearly” part that’s important here. Microscopic spaces between the staves and the heads and around the bung hole allow a minute amount of evaporation. Over time, which ranges from a few months to several years, liquid evaporates through the various gaps in the barrel, to be replaced by air. This condenses the wine, making it richer while adding subtle amounts of oxygen. The loss -- the angel’s share -- can range from 5% of the volume to as much as 20% before the wine is ready to offer to the market. On the down side, that loss in volume must be regularly made up. While the ‘micro-oxygenation’ that barrels add is beneficial, too much will often yield an oxidized wine, so winemakers routinely top up the barrels with the same (or similar) wine kept in reserve. In the case of older or large barrels, it’s principally the angel’s share at work, since these barrels contribute little in the way of oak character. Either way, the finished wine is softer, more complex and more concentrated than its younger self.