***Lecture 7 - Grape Verasion & Harvest .docx - Lecture #7...

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Lecture #7Mid-August to late November is average harvest time in Northern HemisphereoFlipped in southern hemisphereExact time to harvest is determined by the ripeness of the grape as measured by sugar,acid, and tannin levelsoWinemakers also base their decision to pick based on the style of wine they wishto produceIt changes throughout the ripening/harvest seasonYou could make an entirely different composition out of an entirelydifferent grapeoOther consideration is the type of grape you are growingHow good was the season, how much longer do we let it sit on the wineIn general, first stage is that the grape just growsoUse solar energy to make grapesoLoad up with organic acids to make bigger and start putting sugar intoNot a matter of the leaves and solar energy to make sugar… grapes undergo morechanges that simply just getting biggeroVeraison: represents the transition from berry growth to grape ripeningBoyer doesn’t even know if this term is FrenchChemically change the berry into something elseDuring Verasiono1. The colors of the grape take formRed/black or yellow/green depending on the grape varietiesUP TO THIS POINT, ALL GRAPES ARE JUST GREENIf a white/green/yellow skin grape: they do not take on much colorRed grapes take on coloro2. The berries start to soften as they build up sugarsMostly organic acids and solids beforeJuly onwards, they get softer and softer up until they rot in the vine inNovember/December if you let them sit on the vine that longo3. The berries begin to grow dramatically as they accumulate glucose andfructoseo4. (most importantly), pH increases as acids (mostly malic acids) decreaseMain acids to know:Tartaric: remain about the same throughout veraison and theharvest seasonMalic acid: are burned up during respiration throughout theripening/harvest seasonBefore version: the little green balls of grapes have all these acids already in themoThroughout the veraison, malic starts to go away (not all of it)oBefore, the grapes are the most acidic they are ever going to beBecomes less acidic as they stay on the vineWill be lower in acids
GOOD!!! As the growing season length increases, sugars (alcohol) increases, colors(tannins) increases, and overall acids (malic) DECREASESoNo frost, great sunshine, everything has gone great, was a longer warmer seasonoGreen grapes (like chardonnay), it doesn’t matter how long they sit in thevineyard since they won’t turn redoCabernet Sauvignon: red grapeIf it was a shorter season, it won’t pick up as much colorLike Zinfandel or Cerroir? Sryah?oThere are some reds that due to their genetic code, just don’t get that darkPinot Noir (light red grape, will achieve maximum color)oMalic acids are the ONLY THING TO DECREASEOverall acidity will go downGreen/white grapes (chardonnay, Riesling, sauvignon blanc)oThey will not pick up any more color, no matter how long the growing season isoRipen sooner, as they don’t have to wait on coloro

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Term
Spring
Professor
BOYER
Tags
Sauvignon blanc, July

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