|   As with any occupation, winegrowing jargon can be 
        both extensive and forbidding, so here's a quick look into some of the 
        terms used by the people in Life in Vine. Since the documentary 
        covers only part of the winemaking process (growing grapes and processing 
        them, not really winemaking itself) this guide is by no means exhaustive. 
        There are as many vineyard management techniques and variations as there 
        are growers and winemakers, so a breezy overview like this one could never 
        hope to capture them all -- for that, the comprehensive Oxford Companion 
        to Wine should weigh down your shelf. But if learning the jargon is 
        half of turning pro, this glossary will put you a quarter of the way there. 
         AcidAcid -- think of lemon juice or orange juice -- is one of a few elemental 
        components in grapes and ultimately in wine. Generally speaking, growers 
        and winemakers are looking for balance in what they taste: enough acid 
        to make flavors vivid, but not so much puckering is the only recourse. 
        Like tannins, acids help give wines structure. The level of acid is also an indication of ripeness. As grapes approach ripeness, the amount of acid in them drops as the sugar in them rises: winemakers want to pick when the two are in balance, and while lab work will usually tell them when they're close, it's ultimately a matter of experience and preference. BeerA fermented malt beverage critical to the winemaking process, especially 
        after a late night crush. BehindHow can a crop be "behind" schedule, and who cares if it is? The 
        issue is at the heart of why '99 was such a cliffhanger of a year in Northern 
        Oregon's Willamette Valley, and it boils down to this: - every region has a certain window of time during the year when it's 
        warm enough for seasonal crops to grow. In the Willamette 
        Valley, where Life in Vine takes place, it's about 7.5 months, and it 
        doesn't change much from year to year.So, crunching the numbers with Einstein-like speed, we see that 7.5 months 
        of growing season minus the 7.5 months it takes to ripen Pinot Noir doesn't 
        leave a lot to work with. So, if some milestone in the vines' year is 
        delayed -- budbreak is late because it's too cold; it takes the vines 
        longer to flower because it's raining, and so on 
        -- then the time it takes for a vine to go from budbreak to ripeness takes 
        more time than will fit in the growing season. In that case, growers can 
        watch, powerless, as winter storms bear down on their not-quite-ripe fruit, 
        knowing that there might not be enough warmth left in the year to get 
        them the ripeness they need. - unless some stage in its development is delayed, every grape variety requires a certain amount of time to grow and produce ripe fruit, and this is also fairly constant. For Pinot Noir in the Willamette Valley, it's about 7.5 months from budbreak to harvest. This misalignment of growing season and grape ripening -- where the grapes are behind -- is essentially what drives the story of Life in Vine. BloomSometime in the late spring, the vines will offer up spindly little pod 
        clusters. Ultimately, these will bloom into flowers, 
        each of which, in turn, will turn into a grape if growers are lucky. Growers 
        refer to the whole process as bloom. In Life in Vine, Westrey's David 
        Autrey says that despite how late the flowering occurred in 1999, Abbey 
        Ridge Vineyard "bloomed very quickly and very evenly." Brix, DegreesIf you only hear it and don't read it, brix is one of the oddest terms winemakers 
        use. Bricks of what? But "brix" is really a measure of the amount 
        of sugar in juice. Since the process of fermentation 
        takes the sugar in juice and turns it into alcohol, brix also tells winemakers 
        how alcoholic a wine will be. BudThis little fellow is the smallest unit of currency on a vine, and the beginning 
        of a year's worth of growth. See budbreak, and 
        in another sense, see beer. Bud positionIt's done a little differently everywhere, but in general, when growers 
        prune their vines, they cut away everything but 
        a few good-looking canes and lay them down on a trellis 
        wire. These select canes are often very long, so they need to be trimmed, 
        and one way growers determine where to cut is to count the number of nodes 
        -- or bud positions -- on a cane. These are like knuckles on a hand, and 
        it's from these periodic lumps along a cane that shoots 
        will grow. If you leave too few, you get less fruit; if you leave too 
        many, you get a sun-blocking forest of leaves, and the vine has to divide 
        its energy between more clusters, producing poorer fruit. BudbreakSometime in the early spring after the sap begins to flow through the trunk 
        and canes of a vine (usually when the average ground temperature hits 
        50 degrees or so), nondescript bumps on the canes will begin to swell 
        and buds will emerge. Soon, they'll break open and shoots 
        will begin to, well, shoot upward. From a bunch of spindly sticks to shoots, 
        it all happens pretty fast, so Eyrie's David Lett is right when he says 
        in Life in Vine, "there's a lot of magic in there." CaneA cane is like the limb of a vine. Pruners take a cane sprouting from the 
        trunk of a vine and lay it down on a trellis wire. They count the number 
        of bud positions, and trim the cane accordingly, 
        and from these bud positions, shoots will emerge and thicken to canes 
        themselves, reaching for the sky and ultimately setting 1-3 clusters of 
        grapes. After harvest, growers will choose one of these canes (now called 
        a fruiting cane), cut away the rest, and lay it down on the wire to begin 
        the process again. Deja-vu, anyone? Cannon (Propane)As harvest approaches, visitors to vineyards may think they're entering 
        a war zone, but it's really just propane cannons going off. The idea is 
        to scare the bejeesus out of birds who might otherwise be tempted to stop 
        in vineyards for a snack as they migrate north. Unfortunately, this trick 
        doesn't always work: I've seen birds become so acclimatized to the cannon 
        that they'll perch on the weapon itself, hopping a few inches in the air 
        as it goes off before settling down again. CapOnce fermentation begins in red wines, yeasts produce 
        heat and CO2 as they convert sugar to alcohol. This 
        gas rises to the top, pushing grape skins to the top of the fermenter, 
        and this thick layer is called a cap. To keep the ferment 
        from getting too hot, and to extract the right amount of color and tannin 
        from the grape skins, this cap must be broken (punched 
        down) at least twice a day. In Life in Vine, Westrey's David 
        Autrey does this with a large metal plunger, but as you see from his efforts, 
        it's pretty hard work. Wines made in larger fermenters can produce caps 
        so thick and hard that they need hydraulic plungers to break the cap -- 
        some can get so thick you can almost walk on them. Incidentally, not everyone punches down: some winemaker simply pump wine from the bottom of the fermenter and pour it over the cap. That's pretty tricky, but it's nothing compared to the traditional method of breaking the cap, practiced in some wineries around the world to this day: use your body as a human swizzle stick. If you like wine, it doesn't get any better than immersing yourself in what is essentially a hot tub of it. Carbon dioxideA clear gas which is the byproduct of fermentation. As yeasts 
        work their way through the must gobbling up sugar, 
        they produce both alcohol and carbon dioxide. Since 
        CO2 is heavier then air, it tends to well up in the top of an actively 
        fermenting fermenter, so winemakers must be careful 
        their wineries are well aerated. CrushThis term is used specifically to describe the de-stemming process (see 
        crusher), but it's also used generally to indicate 
        the entirety of grape processing, from the time they enter the winery 
        to the time they're safely in barrel. Winemakers often 
        try to get unsuspecting friends and associates to "work a crush", 
        but while it's hard, sticky work, the atmosphere is always festive. And 
        it tends to produce future winemakers... CrusherWhen grapes come into a winery, winemakers usually (though not always) want 
        to separate the berries from the stems, since stems left attached can 
        impart a green, woody flavor to the finished wine. Depending on the kind 
        of grape variety they're fermenting, they may also want those berries 
        broken open a little so yeasts can get right to work 
        on the juice. In days of yore, winemakers accomplished this potentially tedious chore by simply dumping the grape clusters into a vat and walking on them, fishing out stems as their winemaking style (and the amount of wine they drank during this especially festive time of the year) dictated. Thus the purple feet winemakers are famous for having, even if virtually none of them do anymore. That work is more efficiently done by a "crusher", which doesn't actually crush the grapes but (depending on how expensive a model you have) gently sucks them off the stems and breaks the berries just enough to let in the reveling yeasts. FermenterThe vessel in which fermentation occurs. Like you couldn't have guessed 
        that, but you may not have known that fermenters come in all shapes and 
        sizes, from towering stainless steel cylinders to 5-foot-tall plastic 
        boxes to concrete vats to food-grade garbage cans. FlowerWhen I was first told I was in a flowering vineyard, I thought I must be 
        missing something. I looked everywhere, but I couldn't find any of the 
        lush, big-petaled flowers I was sure a wine-producing vine must surely 
        have. When the grower pointed out the actual flowers, I thought he was 
        joking. It is true that if your sweetheart is mad at you, a bouquet of grape flowers probably won't do the trick -- they're small, spindly, and attached like lint to green, cocktail-weenie-like cores. But it's from each one of these tiny flowers that a grape will grow if pollinated successfully, so they're critical to the grape growing process. That's a pretty big if, by the way. Wind, rain, or cold weather can deter flowers from pollinating, and that can set crops behind schedule if not severely limit them. It's the part of the year in which growers feel the most powerless: all they can do is watch and pray for warmth and calm. Free RunWhen a red wine is finished fermenting, it must be separated from the grape 
        skins it's been soaking in. A wine press does this 
        pretty well, but a press will also tend to squeeze out more tannins 
        from the skins than a wine can handle. That's why winemakers often let 
        the juice drain from the fermenter first: this "free run" wine 
        will generally make a more balanced, fruitier wine, though winemakers 
        may add some of the subsequent "press run" 
        to the blend to give it some tannic backbone. Fruiting CaneSee cane. Fruit flavorsWhen winemakers say they taste banana or raspberry -- or old socks, for 
        that matter -- they're not saying that those things have actually been 
        squeezed into grapes or wines. As grapes ripen, and as they become wine, 
        their chemical composition changes, and some of these chemical compounds 
        are remarkably similar to those of other, non-grape flavors. They're so 
        similar, in fact, that they trigger an association in the person tasting. 
        In the case of old socks, this is not always a good thing. Marginal climateWhen Eyrie's David Lett says that Oregon and France's Burgundy region are 
        "marginal climates," he's talking about how tricky it is to get fruit 
        ripe in these areas. These areas are far enough north 
        (or in the case of New Zealand in the southern hemisphere, south) that 
        fruit barely has enough time to get ripe before winter cools things down 
        and stops the show. Some winemakers -- especially Lett, who planted the 
        first Pinot Noir and Pinot Gris vines in the Willamette Valley more than 
        30 years ago on the principle -- believe this makes for better, more complex 
        wines. It also makes for a wilder ride, as Life in Vine shows. MustAfter winemakers crush their grapes, but before they have actual wine, they 
        have must. It's into the must that they'll pitch their yeast 
        to start fermentation. A term in use for at least a thousand years, its 
        origin is unclear. Perhaps: "this must be a mess of grape goo!"? NugginsA highly technical wine term used by a winemaker in Life in Vine 
        to describe a part of his naked body. Perhaps you'll have to buy 
        a copy of the documentary to find out which part... Oak (Barrel)Much, but by no means all wine is stored and aged in oak barrels. Lightly 
        charred on the inside, they may impart a toasty, vanillin smell to the 
        wine and help it mature. Winemaking usage often includes "on oak", as 
        in "we put the Pinot Noir on oak for 10 months." If winemakers put too 
        much oak on, usage can further be modified to "so much oak it's like sucking 
        a 2x4." pHFor many, pH is the Rosetta Stone of winemaking. It measures the concentration 
        of hydrogen ions in grapes, wines or soils, which is to say, their active 
        acidity. In juice or wine, a low pH indicates that the acids 
        are still high and the liquid will taste tart, while a high pH means they're 
        low and the liquid will taste flat. In Life in Vine, when Cameron Winery's 
        John Paul says his pH is 3.14 and "nyaaaah", he's saying that it's still 
        a little lower than the ideal of somewhere between 3.2 and 3.4. Picking WindowThe picking window is the time between when the grapes are ripe 
        enough to use and when winter, rain or birds yank the ripe fruit away. 
        Depending on where grapes are grown, it might be large enough to walk 
        through, or small enough to fit only a piece of paper scrawled with a 
        prayer. In Life in Vine, winemakers are worried that because the grapes 
        are behind schedule, their picking window may not 
        even open. Pinot Noir"Pee-no nwar" is a kind of grape, or variety. 
        There are literally thousands of grape varieties in the world, but the 
        most commonly known in the US are Cabernet Sauvignon, Chardonnay and Merlot. 
        Pinot Noir is the grape used to make red wines in France's famous Burgundy 
        region, but it is also planted in other cooler climates around the world 
        like coastal California, New Zealand, and most famously (after Life in Vine) Oregon. PressAfter stomping grapes with your feet (which is rarely done these days, and 
        then only for show), pressing wine may be the practice most famously associated 
        with making wine. It's a way of squeezing everything you can out of a 
        grape, and after it's finished, the remains can feel nearly bone dry. Pressing happens at different stages in the winemaking process depending on whether white or red wine is being made. In many ways, it's a matter of how long you want the juice in contact with the skins of a grape. Since white winemakers want a light, clear wine, they crush the grapes and send the goo directly into the press for squeezing. Only then do they add yeast and get fermentation going. Red winemakers like those featured in Life in Vine, however, want the color and tannin that prolonged skin contact provides, so their crushed grapes go into a fermenter, where yeast is added to start fermentation. Only when fermentation is over is the wine pressed. PruningPruning can be a cold, wet, and unglamorous activity which is nevertheless 
        critical to a good harvest. Pruning essentially cuts away enough of the 
        vine so its energy can be focused on ripening fruit 
        efficiently. In general, growers cut away most of the canes 
        left over from the previous year's activity, leaving a few which will, 
        in turn, produce shoots which grow into canes which 
        produce fruit. As Eyrie's David Lett says in Life in Vine, "pruning sets 
        the stage for harvest." Punch downDuring fermentation, carbon dioxide pushes grape skins 
        to the top of the fermenter, forming a cap. 
        Left undisturbed, it becomes a kind of blanket and temperatures can get 
        disastrously high underneath and all kinds of unpleasant microbial activity 
        can result, changing the taste of the wine for the worse. So, usually 
        twice a day at least, winemakers must "punch down" the cap to ensure a 
        healthy fermentation, which also extracts more color and tannin 
        from the skins as a bonus. Depending on the size of the fermenter, the 
        cap can be so thick and solid that you can literally stand on it, but 
        no matter what size, punching down is hard work. Many winemakers have 
        hydraulic gizmos to help them, or they use pumps to "pump over" juice 
        from underneath the cap over its top. In Life in Vine, Westrey's David 
        Autrey does it the old fashioned way. RainIf you're used to rain saving the farm, the idea that it can be bad for an 
        agricultural crop may sound a little strange. It is true that rain is 
        important to vines, especially over the winter and early spring, when 
        the water soaks into the ground and, ideally, is stored for use through 
        at least some of the dry summer months. But once harvest draws near, rain 
        is a predator. At best, rain brings with it cooler weather, and that can 
        slow the ripening process, pushing harvest closer 
        and closer to cooler weather when the grapes will simply stop ripening. 
        But rain can also dilute grapes, making watery wine, and worse, it can 
        swell the grapes so much that they burst and expose the grapes to rot 
        and other disease, compromising the whole crop. If it's late September 
        (in the northern hemisphere) and it's raining where you are, a grower 
        somewhere is probably grumbling. Red grapesRed grapes are, uh, grapes which are red. To this soaring platitude I add: 
        red grapes are different from white grapes. What do I win, Johnny? As dumb as it might sound, however, it's important to make a distinction between red wine grapes and white wine grapes, for the simple reason that they're processed differently and make different wines. Both kinds of grapes follow the same arc of budbreak to flowering to ripeness, though growers may coax them along with different techniques, and they may be picked at different times. And at the winery, the first stop for both will usually be the crusher (with some variation based on the style and flavor of the wine envisioned), which will separate the berries from the stems. But once the grapes have run this harrowing gauntlet, their fates diverge. That's because of their skins. Grape skins give wines much of their tannin, which can add backbone and a little longevity to the finished wine. White wines, however, get most of their backbone from acid, and in fact, too much tannin can make a white wine kind of gritty (yum). So as soon as the grapes safely pass the crusher, winemakers will want to separate the juice from the skins as quickly as possible, so they send them directly to the press. After press, the juice goes straight to the fermenter to begin its transformation into wine. Where red wine grapes are concerned, by contrast, winemakers want tannin. In fact, they crave it -- so much that some will let the juice soak on the skins for weeks before they even pitch any yeast. In any case, red winemakers (like those in Life in Vine) send the whole mess, skins and all, straight to the fermenter. This goo, by the way, is called a must. Only after fermentation is complete does the wine see the press. Renewal SpurDuring winter pruning, growers cut back a vine to a 
        few bare canes. This is done differently all over 
        the world, but in Northern Oregon, it often results in a kind of T shape, 
        leaving a main trunk and two canes each heading different directions down 
        the trellis wire. From these canes new canes will sprout in the spring, 
        and one of these will in turn get laid down on the wire to begin the process 
        again the next winter. Nevertheless, some growers like to have a little 
        insurance that they'll have quality canes close to the trunk, so they 
        leave little spurs behind in addition to the two canes. Usually, these 
        little spurs are short enough they'll only produce two sprouts, but the 
        two canes that grow out of them are nicely positioned for the following 
        year. Residual SugarResidual sugar is sugar left un-converted by yeasts during 
        fermentation. Given the right conditions, once the yeasts get to work 
        in a fermentation, they usually tear off the rear view mirror and don't 
        stop until they've converted all the sugar to alcohol and carbon 
        dioxide. But it's important for winemakers to know whether they've 
        finished or how far they are away from doing so, because once they stop, 
        they'll stop producing CO2, which protects the new wine from the ravages 
        of oxygen. Some winemakers also like to finish the last little bit of 
        fermentation in a barrel to help soften the wine. Whatever 
        the reason, they often take repeated measurements of residual sugar as 
        the end of fermentation draws near, usually with a diabetes test kit, 
        as it turns out. In Life in Vine, Doug Tunnell's wines have reached 
        .1% residual sugar, which is the point at which he wants to press. See also sugar. RipeAs Shakespeare's Edgar says in King Lear, "Ripeness is all!" Though the character 
        is actually talking about something else (death, despair, fate, the usual 
        peppy Lear topics), he couldn't have described the ultimate goal of grape 
        growing more perfectly. The trouble is, however, that there's no objective 
        standard of what's ripe. As we see in Life in Vine, while Westrey's David 
        Autrey and Amy Wesselman take a similar tack as Cameron's John Paul about 
        deciding when to pick, they each have their personal strategies based 
        on their experience and the wines they like to make. Fifteen years ago, 
        many winemakers simply went by the numbers: when grapes reached 23 Brix 
        (for instance), they came off the vines with no ifs, ands or buts. But 
        these days, higher-end winemakers rely on their sense of taste to decide 
        ripeness, looking for ripe and mature berry flavors with no green vegetal 
        components. RotRot -- or botrytis bunch rot -- is the scourge of late harvests, and it can 
        wipe out whole vineyards in a few days. This fungal disease can take many 
        forms, but at its worst, it spreads over berries and breaks down the skins, 
        and the result is downright ugly. Worse, it can give wines made from the 
        grapes it infests a moldy, vinegary taste, so winemakers who spot it will 
        often spend untold hours sorting their fruit in a grim attempt to minimize 
        the damage. In general, rot flourishes in moist, still, and lukewarm environments 
        as the grapes near ripeness, so growers often pay 
        special attention to retaining airflow around their grapes. As an aside, not all rots are shunned. One form is called noble rot, and winemakers bent on making sweet, late harvest wines welcome it. Coveting botrytized grapes is most famously practiced in Sauternes, a region within the Bordeaux appellation in France, but late harvest winemakers in Germany and the US also seek it out. SetAlso known as "fruit set," this is a term used by growers to refer 
        to how successfully a the flowers in a vineyard 
        have pollinated -- as in, "we had a good set this year". In 
        other words, since these flowers will grow into grapes, the quality of 
        the set will determine how good the crop will be months later. ShootThis term for the part of the vine which emerges from a young bud 
        is no understatement. Unless the weather is unforgivingly cold, shoots 
        will literally shoot upwards, growing perceptibly in just one day. SprayingEspecially in Oregon, but in other wine regions as well, growers can't simply 
        prune the vines and then kick back until harvest. 
        Among other things, they need to constantly monitor the vines for disease, 
        which means they need to spray their vineyards periodically. In Oregon, 
        the chief scourge is powdery mildew, which many growers combat by spraying 
        sulfur every 1-2 weeks like clockwork. While there are other more high 
        tech chemicals available, sulfur is gentler on the vineyard's ecosystem, 
        and promotes fewer side effects. In fact, spraying sulfur is even considered 
        "organic." SugarIn many ways, sugar is the reason you're here, reading this glossary. 
        It's certainly the engine that drives the wine industry, because without 
        sugar, yeasts would yawn at the sight of grapes and 
        never transform them into wine. The chemical evolution of sugar (or glucose) 
        into alcohol is complex, but it occurs naturally and almost anywhere -- 
        the spritz you taste in the apple cider you left too long in the back 
        of the fridge tells you that you probably have a little less sugar in 
        the juice than when you bought it. See also Residual Sugar. TanninTannin is the primary culprit behind a surprising amount of wine babble -- 
        "structure", "backbone", even "grip". But 
        that's because tannin is so central to the way a (red) wine tastes, and 
        therefore, how critical it is in the winemaking process. If you can imagine over-steeped tea -- or sucking on a tea bag -- that's tannin. Of course, any wine that tastes like over-steeped tea would be a difficult sell, so winemakers try to get just the right amount, enough to add a firmness to the wine without making the wine bitterly astringent. Tannin is most often found in red wines, and that's because most of the tannin in grapes comes from the skins -- in general, red wines ferment on the grape skins, white wines do not. But prolonged storage in new or newer oak barrels can also infuse a wine with tannin, so winemakers will decide how long to keep a wine in barrel in part to determine how much tannin they want in the wine. By the way, tannin isn't the only component in a wine that gives a wine "structure": Acid plays a part, too. Together with tactile impressions of body or alcohol, they're like the framework of a building, and they're what hold a wine together. VarietalSome writers make a distinction between "varietal" and "variety" 
        (a varietal wine being one which is marketed and sold on the basis of 
        its variety), but the distinction is blurring. At the core of both is 
        a reference to the kind of grapes used in making a wine. The most famous 
        (and best-selling) varieties in the marketplace are Cabernet Sauvignon, 
        Chardonnay, and Merlot. They're grown all over the world, but they were 
        made famous in France: Cab (you may have been the victim of bad puns leeched 
        from this abbreviation) and Merlot are two major components in Bordeaux, 
        while Chardonnay is the grape used exclusively in white Burgundy. Pinot Noir, the red wine grape featured in Life in Vine, was also made famous in Burgundy, and it is notoriously difficult to grow well. This, and the popularity of the so-called Big Three varietals mentioned above has kept Pinot's market share comparatively low. In fact, as vineyards around the world are being replanted with the Big Three because they're such cash crops, some people are anxious about a future barreling increasingly toward monoculture. There are thousands of grape varieties in the world (most famously in Italy, with thousands alone), each creating a different kind of wine, and many represent specific regions so exclusively that their wines are essentially the flavor of their towns or districts. As growers see how much more money they can make growing Cabernet, some often uproot their old, characterful vines along with centuries of tradition, propelling the world one bit closer to bland uniformity. But I don't really have any opinion on this... VeraisonVeraison ("vuh-RAY-zon") is a truly magical time in the grape growing 
        year. Before veraison, red wine grapes are green, 
        bitter and hard, poor fodder for glossy coffee table books. But toward 
        the end of the summer, over about a week or so, their color changes to 
        a more appetizing deep purple. On the way, vineyards are decked multicolored 
        clusters, since each grape within a cluster changes on its own timetable. 
        With a little backlighting, the result is amazing to behold. Veraison tells growers that the ripening process which will culminate in harvest has begun, since red grapes change color when the sugar in them increases to 5-10 brix. White wine grapes also change color about this time, but the change is much more subtle. Vintage Vintage sounds like a word you'd say with your nose in the air and an ascot 
        tied around your neck. But this snobby-sounding word is used by winemakers 
        in a much more functional way to essentially indicate a winemaking year. 
        Life in Vine, for example, covers the entirety of "the '99 
        vintage." On the shelf, wines are often classified by vintage, both to keep one year's produce separate from another, and to indicate a certain quality level. If you don't see a date on a bottle of wine, it's what's called a "non-vintage" wine, which means it's a blend of wines from at least two different years. When wineries issue both vintage and non-vintage wines, the vintage-dated bottles are almost marketed as better wines, but at a higher price. ViticultureViticulture is the science and practice of growing grapes, most famously taught 
        in the United States at the University of California at Davis. Compare 
        to "enology," the science and practice of making wine. White GrapesSee Red Grapes. YeastYeasts are the high livin' dynamos that take gray, mucky grape juice and transform 
        it into wine. Yeasts are everywhere. There are untold strains of them 
        in the world and they float around virtually everywhere, poised to ferment 
        something at a moment's notice. The popular conception that yeast gobble up sugar and spit sugar, heat and carbon dioxide out the other side isn't exactly right, but it's close enough (a mercenary enzyme also plays a part). But as festive a process as that might be, it ultimately ends in tragedy -- as the yeasts convert sugar to alcohol, the alcohol level rises, and after a while, it actually kills them off. How's that for a morality play? That's why winemakers must always be careful which yeasts dominate their fermentations. Not only will different yeasts impart different flavors to a wine, but they'll also give up at different alcohol levels. If a wimpy yeast gets the upper hand in the fermentation, they might stop after processing only half the sugar. The result is a "stuck fermentation", and that is a winemaker's kryptonite (though it is what gave us Kendall-Jackson Vintners Reserve Chardonnay). The danger of a stuck fermentation is why many winemakers use yeasts isolated and cultured in the lab -- they know what they're going to get. But more and more winemakers (and many in Life in Vine) like the complexity and naturalness so-called "wild yeasts" give to a wine. Luckily, yeasts which successfully dominate a fermentation tend to hang around for more action the following year, so wineries tend to maintain a population which can do the job. Nevertheless, many winemakers have cultured yeasts on standby in case the unthinkable should occur. return to the top |