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Mapleton, North Dakota HO HO HO O O HO HO HO HO O The Chemistry The of Chemistry Grapes and Montana Grape and Montana Grape Association ConferenceWinery OH O O O O OH Message in a Bottle: O OH O OH 183.84 OH OH W 74 Greg Cook 4e Winery 6 2018 April 126.90 53 I N 20.180 10 e

HO O OH OH O OH 1 Mapleton, North Dakota • What is Wine? it will sicken and die.” treated with reasonable respect age and death. When not youth,comprises maturity, old no preservatives. Its life cycle “Wine is a living liquid containing ~ ~ Julia Child

2 Mapleton, North Dakota • • • • TTB Definition for tax purposes (C) is for nonindustrial use.”(C) is for nonindustrial and mixtures thereof by whatever process produced; and more than 24 percent alcohol by volume, including all dilutions (B) contains not less than 0.5 percent alcohol by volume and not products; or agricultural fruits (A) is made on a bonded wine premises from grapes, other "wine" means term The “any class and type of product that is . . 3 Mapleton, North Dakota • • • • • How Wine is Made (from grapes) skins away from skins Yeast is added to the must with the Red wines - fermented White wines - juice is pressed are crushed Grapes are grown Grapes • • • • barrels, and bottled allowed to clear malic to lactic converting sugar to alcohol Wine is aged, often in oak wine is After fermentation may ML fermentation be done converting ensues Fermentation 4 Mapleton, North Dakota • • • • • Components of grapes ~1% Esters,~1% Polyphenols, Vitamins, Minerals, Flavonoids, Tannins Proteins/Amino~1% 0.3-1.5% Acids 18-30% Sugars 70-80% Water 5 Mapleton, North Dakota • • Grape Ripening fall throughout ripening. and molecules also rise Tannins, and flavor colors and acids fall. After veraison, rise sugars 6 Mapleton, North Dakota Anatomy of a Grape Stems, Seeds Astringent Tannins Water Sugars Pulp Acids Anthocyanins Resveratrol Quercetin Catechins Tannins Skins 7 Mapleton, North Dakota The Critical The Chemistry Critical • C (sugar) () 6 H 12 • O • Sugar level in grapes = °Brix Sugar level in grapes 6 1° Brix = 1% sugar 0.55% ethanol 1° Brix 2 C yeast 2 H 5 OH + 2 OH CO 2

8 Mapleton, North Dakota Fermentable sugars • • • • • Non-fermentable sugars may be present - Non-fermentable sugars Arabinose, Rhamnose, Xylose sugar metabolized by yeast is the first tastes about 2x’sFructose as sweet as glucose Over-ripened have grapes more levels are about even glucose and fructose At harvest HO HO D-glucose OH O OH OH HO HO D-fructose O OH OH OH 9 Mapleton, North Dakota Tannins • • • • • • Polymerize over time and drop out, softening a wine (condensed) Two - hydolyzable main kinds in grapes and non-hydrolyzable found in the skins, In grapes seeds and stems hides into leather term The Plant Polyphenols and bitter flavors, - astringent antioxidants proteins polyphenolic to any compounds that can bind to now large refers tannin derived from wood derived tannins used to tan animal 10 Mapleton, North Dakota • Hydrolyzable Tannins compounds like gallic acid or ellagic acid Hydrolyzable tannins have core bound to a carbohydrate HO HO HO O O HO HO HO HO Tannic Acid O OH O O O O OH O OH O OH HO OH OH gallic acid O OH OH OH HO HO O O ellagic acid O O 11 OH OH Mapleton, North Dakota Condensed • potential. colors, astringency, aging responsiblelargely for of flavonolsoligomers Condensed tannins are O O flavon-3-ol OH HO OH O O epicatechin OH HO OH OH OH O OH OH HO OH R R 6 7 HO OH R HO OH O 5 OH OH O O OH O R = H, OH, OCH OH, H, R= anthocyanins R OH OH 3 OH R 3' OH OH R R OH OH 5' 4' n 3 12 Mapleton, North Dakota Wine Wine Color White White Wines Brown Amber Yellow Gold Straw Green Red Wines Brown Mahogany Brick Deep Red Ruby Red Purple 13 Mapleton, North Dakota Color in Wine • • • • • • pyruvic acid and acetaldehyde pyruvic react with tannins antioxidants flavorless and nearly odorless (depends on pH) Anthocyanins are water soluble pigments - purple, red, blue colors Found mostly in the skins Phenolic Compounds - anthocyanins

HO OH O anthocyanins O R Glu OH R 14 Mapleton, North Dakota CHEMISTRY DEMONSTRATION HO LOW pH OH O red to purple redto cation O R Glu OH R HIGH pH O OH O blue to green to blue quinone O R Glu OH R 15 Mapleton, North Dakota Low pH ...... pH . Neutral ...... High pH CHEMISTRY DEMONSTRATION HO LOW pH OH Pigments from Red Cabbage O red to purple redto cation O R Glu OH R HIGH pH O OH O blue to green to blue quinone O R Glu OH R 15 Mapleton, North Dakota Flavors and Aromas in Wine methoxypyrazines (geraniol, nerol, norisoprenoids monoterpenes demascenone, mercaptans zingerone) (vanillin, linalool)

H N N 3 HO H C O S S OCH H H 3 bell pepper,bell asparagus tropical fruits, rubber herbaceous, grassy, rotten eggs, rotten cabbage, cat urine, spices, raspberry, floral aromatics vanilla, rose oil most wines can have cabernet sauvignon gewürztraminer sauvignon blanc chardonnay pinot noir riesling muscat these syrah 16 Mapleton, North Dakota Is it a flaw? O S S H H S H O OH O 17 Mapleton, North Dakota Acidity Distilled Distilled (5%) Tomato juice Lemon Juice Coca Cola Coffee Wine Water Item Milk 3.0-3.5 4.1-4.6 2.8-3.2 2.4-3.0 1.8-2.3 pH 7.0 6.8 5.5 18 Mapleton, North Dakota • Acids in Grapes Primary acids are and malic acid. acid. Some citric acids are tartaric Primary HO

Tartaric O OH OH Acid O OH HO

O Malic OH Acid O OH HO O Citric O OH OH Acid O OH 19 Mapleton, North Dakota • “Wine Diamonds” are potassium bitartrate HO

Tartaric O OH OH Acid O OH potassium buffers potassium HO O OH OH bitartrate O O K 20 Mapleton, North Dakota Why do we need to worry about acid? • • • • • • Cold climate hybrid grapes are generally high in acids are generally grapes Cold climate hybrid (precipitates) Wine acids can cause aesthetic problems for wines Provides microbial stability (affects SO Affects the color (anthocyanins) Wine low in acid tastes flat and dull and texture to wine Acid provides brightness 2 ) 21 Mapleton, North Dakota Why Sulfites? • • • • • Can react with anthocyanins reducing color levelsUS allowed - up to 350 ppm Most commercial wine contains 10-40 ppm produced in wine ~ 6 ppm Naturally yeasts and prevents oxidation Sulfite is added to provide SO 2 - antibacterial, kills native 22 Mapleton, North Dakota pH and SO dioxide sulfur sulfur SO 2 + H 2 O 2 H + + bisulfite HSO 3 - 2H + + SO sulfite 3 = 23 Mapleton, North Dakota SO 2 Mapleton, North Dakota pH and SO • (whites) 0.8 ppm ppm (reds), SO molecular protective minimal 2 = 0.5 2 25 Mapleton, North Dakota • Acid Measurements solution) pH • • a ten-fold change in acid strength. scale.pH is a logarithmic A one unit change in pH is equal to in solution to bind protons. specific acid type and buffers including the Acid strength depends on multiple factors - a measure of acid strength (free hydronium in 26 Mapleton, North Dakota • Acid Measurements reactive protons are present . TA • • • Expressed as grams/liter (or percent) of a reference acid. Expressed as grams/liter are adjusted. We can calculate and predict the change in TA acidswhen and is linear. is This direct measurement of the number of acidic protons - acidity is the measure of howTitratable many actual 27 Mapleton, North Dakota pH vs Titratable Acidity H H TA reactive of count = exact groups acid hydroniumpH = measure concentration of ions of O O tartaricacid O O bitartrate OH OH OH OH O O O O H + + H H water water O O H H H O O O O bitartrate OH OH ion ion OH OH O O O O

+ + hydronium hydronium H H ion ion O O H H H H 28 Mapleton, North Dakota • • • Strategies for Managing High Acid Grapes • • • • • Reduce Reduce acidity of must or wine Blend with a low acid wine Do nothing - balance acidity with sweetness bicarbonates) Chemical means (potassium or calcium carbonates/ Cold Stabilization ML fermentation Acid reducing yeasts (dilution with water) Amelioration 29 Mapleton, North Dakota • Balance acidity sweetnesswith Titratable Titratable Acidity and Sweetness Guidelines - Semi Dry(1-4%RS) Our grapescan haveTA’s higherthanthis Sweet (>4%RS) Dry (<1%RS) Sweetness TA ofmust 1.0 -1.3% 0.9 -1.1% 0.8 -0.9% TA ofwine 1.0 -1.1% 0.7 -0.9% 0.6% 30 Mapleton, North Dakota • Blending with Blending awith low acid wine • • • acid wine Acidity can be balanced by blending a high acid wine with a low • to blend to reach a target to blend to reach a target TA Using Pearson’s square, you can calculate the volumes you need wines wines with fruit Blend grape out of state lower from acid grapes - most likely will need to import Grapes pH may be unpredictable 31 Mapleton, North Dakota • Reduce acidity by amelioration • • • Dilute Dilute must with water to reduce acidity May have to add sugar back to reach desired brix flavored grapes. e.g. varieties. Labrusca - best with full-bodied intensly Could dilute flavors and colors Dilute based on TA (not pH) to reach a target TA 32 Mapleton, North Dakota • Acid reducing yeasts • Some Some yeasts metabolize malic acid significant reduction in acidity lactic acid - thus it can have do not form generally These a - Katie Cook http://northerngrapesproject.org/wp-content/uploads/2014/10/Biological-deacidification.pdf Lalvin 71b-1122 Anchor Exotics Uvaferm VRB Maurivin B Lalvin C Yeast Malate reduction up to56% 19 -30% 20 -30% 31 -34% 20% 33 Mapleton, North Dakota • Malolactic Fermentation HO Bacteria convert malic acid into lactic acid convert Bacteria HO O C

O Malic C H H OH C H OH Acid O O C OH OH ml bacteria H C H H

Lactic OH OH C H O Acid O C OH OH + 34 Mapleton, North Dakota • Cold Stabilization two weeks. 25 - 30°F for about Chill the wine down to HO

Tartaric O OH OH Acid O OH

potassium buffers salts potassium HO O OH OH bitartrate O O K 35 Mapleton, North Dakota • • • • Chemical Chemical Deacidification • • • • If adjusting after fermentation - not recommended to reduce If adjusting after fermentation TA more than 0.2% stabilization It introduces K and/or Ca ions into the wine - should be followed up with cold to fermentation used BEST on must prior of the wine acids a portion bases used to neutralize Inorganic best to age at least 6-8 months before bottling. precipitate much slower than potassium . Calcium tartrates it Thus is Calcium Carbonate - CaCO Potassium Bicarbonate - KHCO - K 2 CO 3 3 3 36 Mapleton, North Dakota • • • • • Chemical Chemical Deacidification Chemical neutralization affects Chemical neutralization Tartaric acid first K KHCO CaCO Test to adjusting the bulk. a small sample prior Check pH to make sure it is not thrown way off • • • • • 2 necessary combine with malic reduction techniques to minimize how much chemical deacidifcation is adjustments are made wine may be out of balance in the end if large 0.6 g/L = 1 g/L Titratable Acidity reduction 0.9 g/L = 1 g/L Titratable Acidity reduction 0.67 g/L = 1 g/L Titratable Acidity reduction CO 3 3 3

37 Mapleton, North Dakota • • • • Acid Management forGuidelines high acid wines USUALLY BEST TO FERMENTATIONpH BEFORE ADJUST Keep desired wine style in mind align with these guidelines grapes may not necessarily Our hybrid forpre-fermentation vinifera Optimal acid ranges • • : pH 3.2–3.5, TA 6.0–9.0 g/L, 17–24 ºBrix Red wine: pH 3.4–3.7, TA 6.0–7.0 g/L, 22–25 ºBrix 38 Mapleton, North Dakota • • • Acid Management forGuidelines high acid wines pH >3.2 pH 3.0-3.2 pH < 3.0 • • • • • • • adjustments. Potassium carbonate - for smaller adjustments Cold stabilization if necessary ML Fermentation Cold stabilization (reds or chardonnayML fermentation style whites) Use acid reducing yeast use carbonates to raisemaybe the pH pH >3.2 Calcium carbonate - for large Use carbonates to bring 39 Mapleton, North Dakota • After fermentation adjustments After fermentation and mL After fermentation • • followed by cold stabilization If you need to adjust acid, best to use potassium bicarbonate Blending is the best option • chalky taste - can give a Calcium post fermentation salts not recommended 40 Mapleton, North Dakota • • • Case Study - High Acid Marquette The next The day Thawed Nov 2014 in 2013, and frozen285 pounds of Marquette harvested crushed • • • • pH 3.44 TA 7.5 g/L BRIX 25 CaCO 1 gal must removed and treated with 175 g pH 2.87 TA 8.3 g/L (0.83%) at crush: pH 2.74 TA 13.4 g/L (1.34%) BRIX 24.4 3 for 30 min then added back to the bulk

41 Mapleton, North Dakota • • • Case Study - High Acid Marquette pH 3.55 Ending proceeded for fermentation 5 weeks secondary added on day and 2 of fermentation MBR 31 ML bacteria pressed to produce about 20 gal wine. with Lalvin 71b-1122 for 7 daysFermented on the skin then

42 Mapleton, North Dakota • What is Wine? it will sicken and die.” treated with reasonable respect age and death. When not youth,comprises maturity, old no preservatives. Its life cycle “Wine is a living liquid containing ~ ~ Julia Child

43 Mapleton, North Dakota • What is Wine? its fate.” quality determines the fruit winemaker and chemistry, but ultimately cycle may be guided by a knowledgeable and much more.preservatives Its life polyphenols, esters, tannins, natural sugars, acids, alcohol, terpenes, concoction of chemicals containing, “Wine is an evolving complex ~ ~ Greg Cook

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