Todd Steiner Enology Program Manager & Outreach Specialist Department of Horticulture & Crop Science The Ohio State University/OARDC Wooster, OH 44691
THANK YOU! 2014 Michigan Annual Wine Conference Conference Organizing Committee Nancy Oxley Initial Contact Linda Jones Barb Mutch
GO BUCKEYES!
Wine # 1 White Wine Control: 2011 Pinot Gris
Wine # 2?
Acetic Acid Spoilage (VA) Aroma: A wine measuring high in VA will give off a sharp, pungent vinegar aroma Lesser concentrations below 0.70% can lead to increased complexity depending on variety Cause: Acetobacter and Gluconobacter All belong to the family Acetobacteriaceae
Acetic Acid Spoilage (VA) Cause: Aerobic bacteria metabolism oxidizing ethanol and glucose producing acetic acid Small amounts of ethyl acetate will contribute to a vinegary taint
Acetic Acid Spoilage (VA) Two ways of introduction into must and wine Grapes - damaged or rotten fruit Dirty cellar equipment such as pumps, hoses, tanks and contaminated wooden barrels Provides an indicator of cellar hygiene
Acetic Acid Spoilage (VA) Factors favoring acetic acid production Optimal temperatures vary from 10 C (50 F) to 35 C (95 F) Appearance of acetic acid bacteria may form a film, haze or pellicle located mainly on the surface
Acetic Acid Spoilage (VA) Factors favoring acetic acid production High ph in must or wine Aeration of wine during transfer Headspace levels in tanks and barrels Warm storage temperatures Low sulfur dioxide
Acetic Acid Spoilage (VA) Prevention of acetic acid spoilage Starts in the vineyard with clean fruit avoid rot, high ph or high soluble solids Grapes containing significant amounts of rot should be treated with 50-75 ppm SO 2
Acetic Acid Spoilage (VA) Prevention of acetic acid spoilage Ferment with a commercial recommended strain for the variety you are vinifying Avoid natural fermentations Punch the cap down a minimum of twice daily for red wine fermentations Helps prevent fruit fly inoculation
Acetic Acid Spoilage (VA) Prevention of acetic acid spoilage Once fermentations are complete the proper amount of SO 2 should be added to the wine Monitor and maintain SO 2 levels based on ph to.8 ppm molecular to bottling Keep tanks and barrels topped off Develop a sound sanitation practice
Acetic Acid Spoilage (VA) Remedy: reduction is difficult however, there are several possible solutions Reverse osmosis coupled with ion exchange Oxidative yeast fining utilizing acetic acid as a carbon source Blending may be an option for wines lower in volatile acidity
Acetic Acid Spoilage (VA) Tasting Room Information If suspected, pull from shelf and notify winery owner/winemaker immediately VA flaws are most likely whole tank or bottling related Concentration of VA typically higher in late harvest and dessert wines TTB legal level not to exceed 0.12% in white wine and 0.14% in red wine
Wine # 3?
Oxidized Visual appearance: The appearance of brown tones in a white table wine, brownish-red hues in a red table wine and an orange blush / rose Aroma: Sherry-like or acetaldehyde odor Nutty Almond Loss of fruit and bruised banana (initial stages)
Oxidized Cause: Many compounds found in grapes and wine are readily oxidized These include both enzymatic and nonenzymatic reactions Juice enzymatic oxidation is caused by tyrosinase and laccase oxidizing phenols in the production of brown pigments Hyper oxidation treatments take these enzymatic browning precursors out of the equation
Oxidized Cause: Non-enzymatic oxidation in wine is caused by certain phenols such as catechin and epicatechin in a two-step process forming hydrogen peroxide and oxidizing ethanol to acetaldehyde
Oxidized Factors influencing oxidation Grapes containing rot particularly Botrytis cinerea produce higher amounts of browning enzymes Turbid juice with high solids Oxygen (DO) absorption in wine Increased levels at lower temperatures Process of chemical oxidation occurs faster at warmer temps Low amounts of free sulfur dioxide in must and wine
Oxidized Prevention: Harvest quality grapes with low rot Clarify the juice reducing solids for enzymatic activity and oxidation Fill tanks from bottom when racking over from tank to tank Check pump seals and hoses for leaks or loose fittings in uptake of oxygen Limit wine movement along with movement at cooler temperatures
Oxidized Prevention: Avoid excessive headspace in tanks and barrels Limit uptake of oxygen at bottling line by adding an inert gas to the filling bowl Flush bottles with nitrogen to replace oxygen Provide vacuum at filling and corking in addition to purging headspace with inert gas Use a quality grade closure for the variety being bottled
Oxidized Prevention: The proper use of sulfur dioxide Critical times of addition are to the must, after alcoholic fermentation, cellar aging and bottling It is extremely important to monitor and maintain proper sulfur dioxide levels based on wine ph to.8 ppm molecular (whites) and.6 ppm molecular (reds)
Oxidized Remedy: Excessive oxidation is tough to remedy Carbon filtration extreme remedy Fining agents such as potassium caseinate, PVPP and yeast fining can be possible solutions Lower levels can also utilize blending as tool
Oxidation Tasting Room Information If you notice oxidative characters in a new varietal or blend to the tasting room, notify tasting room manager/winemaker or owner immediately Avoid excessive headspace in bottles for long periods (transfer to splits) Purge bottles with nitrogen, carbon dioxide or argon to replace oxygen Keep bottles in refrigerated tasting cooler Discard wine at first appearance of fruit reduction and replace with fresh bottle
Wine # 4?
High SO 2 Aroma: A wine high in free SO 2 will give off a pungent aroma that will cause a stinging sensation in the nose and throat A wine high in total SO 2 will give off a tinny or metallic characteristic in aroma Taste will produce a long lasting sulfur burning sensation (film) in the back of the throat and on tongue
High SO 2 Cause: By excess addition of sulfur dioxide in the form of gas, potassium metabisulfite or liquid form Sulfur dioxide has a direct relationship to wine ph
Addition of SO 2 to obtain.8 ppm molecular) ph Free SO 2 ph Free SO 2 2.9 11 3.5 40 3.0 13 3.6 50 3.1 16 3.7 63 3.2 21 3.8 79 3.3 26 3.9 99 3.4 32 4.0 125 Source: C. Smith, Enology Briefs, Feb/March, 1982, Univ.. of Calif.., Davis
Free SO 2 (mg/l) Other role of SO 2 : Molecular SO 2 as anti-microbial 275 250 225 200 175 150 125 100 75 50 25 0 2 ppm molecular 0.8 ppm molecular 0.6 ppm molecular 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 Source: Dr. Gavin Sacks, 2014 Ohio Grape and Wine Conference Molecular SO 2 can be calculated from ph and free SO 2 0.6-0.8 ppm (mg/l) molecular SO 2 typical rec for dry wines 2 ppm is approximate sensory threshold of molecular SO 2 ph
High SO 2 Prevention: Make sure calculations are accurate and based on wine ph Additions to the must of up to 50 ppm is recommended and will not be a factor High SO 2 concentrations will be due to excess post fermentation additions Keeping track of our free SO 2 concentrations throughout the vinification process will help prevent this fault (Good recordkeeping)
High SO 2 Remedy: Wines high in SO 2 can be aerated or racked to help lower free SO 2 concentration over time Filtration or wine movement Blending can also be an option
High SO 2 Tasting Room Information TTB regulated limit to 350 ppm total SO 2 Can cause some allergic reactions in humans More realistically from biogenic amines If suspected, pull from shelf and notify tasting room manager, winery owner or winemaker immediately for second opinion Chemical analysis can immediately identify this as a problem in free, total or bound SO 2
Wine # 5?
Hydrogen Sulfide Aroma: Higher levels resemble rotten eggs while lower levels impart a yeasty aroma Also express aromas of sulfur, flatulence and loss of fruit Cause: Yeast metabolic activity of organic, inorganic and elemental sulfur can lead to the production of hydrogen sulfide
Hydrogen Sulfide Factors responsible for H 2 S production Elemental sulfur as a grape fungicide or sulfur candles used in barrel sanitation Musts deficient in assimilable nitrogen (FAN) levels By-product of yeast stress metabolism Individual yeast strains produce differing levels of H 2 S Especially wild or natural yeast strains
Hydrogen Sulfide Factors responsible for H 2 S production High concentrations of insoluble solids Increased must ph Higher fermentation temperatures
Hydrogen Sulfide Prevention: Avoid harvesting grapes prior to 6 weeks of the last sulfur application Use drip less sulfur sticks, sulfur dioxide gas or potassium metabisulfite for sterilization of tanks and barrels Addition of a yeast nutrient such as (DAP) and other essential amino acids such as in Fermaid K
Hydrogen Sulfide Prevention: Add appropriate amount of SO2 at crush Select a commercial strain shown to produce low amounts of hydrogen sulfide Clarify juice lowering the amount of solids Control fermentation temperatures Aerate fermenting must / juice during growth phase Rack of lees when detected
Hydrogen Sulfide Remedy: If detected shortly after alcoholic fermentation try racking or sparging with carbon dioxide or nitrogen Try racking combined with the addition of sulfur dioxide (25 ppm) settle for one week and filtrate
Hydrogen Sulfide Remedy: New product Redulees (Lallemand) has been shown to reduce H 2 S Has Bentonite and other natural elements with Copper Bench trials essential The addition of copper sulfate as a fining agent Bench trials should be performed TTB limits of.5 ppm residual copper in finished wine
Further Reduction of H 2 S Further reduction of H2S can form: Mercaptan: (Ethyl and Methyl) Can be remedied with copper sulfate and or ascorbic acid followed by copper sulfate Disulfide: Copper sulfate fining not possible Bench trials should be performed!
H 2 S Tasting Room Information Varies from loss of varietal fruit, slightly reduced to repulsive odor Represents a whole tank issue If suspected, pull from shelf and notify tasting room manager, winery owner or winemaker immediately for second opinion A penny in the glass or quick CuSO 4 trial can help diagnose the problem
Wine # 6 Red Wine Control: 2010 Cabernet Franc Blend
Wine # 7?
Ethyl Acetate Aroma: Wines high in ethyl acetate express aromas of nail polish, airplane glue, varnish etc. Sensory threshold reported at 150 200 mg/l Lesser concentrations can enhance wine complexity being an aromatic ester and aid in sweetness and richness on the palate
Ethyl Acetate Cause: Formed by esterification of ethanol and acetic acid Off by-product from wild yeast and bacterial Comes into cellar from damaged fruit (rot) Film Yeast: Hansenula, Candida and Pichia Acetic Acid bacetria (AAB) and Lactic Acid Bacteria (LAB) Hanseniaspora and Kloeckera can produce high levels of ethyl acetate during pre-fermentation processing mainly during cold soak and/or lowtemperature fermentation
Ethyl Acetate Prevention: Continually pick rot out in the vineyard Minimize time from harvest to cellar Grapes should be cooled immediately after harvesting Utilize sorting tables prior to destemming and crushing in limiting rot prior to fermentation
Ethyl Acetate Prevention: Avoid cold soak procedures in years with high microbial load from vineyard Add 50 ppm SO 2 to red must Lower levels of SO 2 to cold soak treatments Utilize a good commercial yeast strain
Ethyl Acetate Prevention: Utilize Lysozyme against gram + bacteria (LAB) In case of film yeast, avoid headspace in tanks and barrels (highly aerobic) purge transfer lines, pumps, and receiving tanks with an inert gas such as nitrogen
Ethyl Acetate Remedy: Lower concentrations can utilize blending as a tool in lowering to acceptable thresholds Higher concentrations are difficult to remedy Reverse osmosis coupled with ion exchange mostly for taking out VA
Ethyl Acetate Tasting Room Information Unlike VA, no legal limit on ethyl acetate Most likely affects whole tank or barrel If suspected, pull from shelf and notify tasting room manager, winemaker or winery owner immediately May indicate sanitation problems in winery or help future harvest and cellar protocols
Wine # 8?
Geranium Taint Aroma: Resembles geranium plants Cause: Caused by the presence of certain strains of lactic acid bacteria and their metabolism of sorbic acid present in wine containing residual sugar at bottling
Geranium Taint Factors contributing to geranium taint Wines with some residual sugar may have sorbic acid added to prevent re-fermentation by yeast
Geranium Taint Prevention: Keep free sulfur dioxide levels at sufficient concentrations to prevent lactic acid bacteria growth (grapes and wine) Can also use Lysozyme to control Lactic Acid bacterial growth in wine Addition of sorbic acid should be accomplished just prior to bottling with appropriate SO2 levels
Geranium Taint Remedy: Wines infected with geranium taint are nearly pointless to remedy The blending ratio of sound to defective wine is high at 11:1 making it not very cost effective If noticed at early stages, wine can be saved Shows importance of keeping track of wine in cellar Therefore prevention is the obvious cure
Geranium Taint Tasting Room Information Not harmful Offensive odor at higher concentrations Represents a whole tank issue If suspected, pull from shelf and notify tasting room manager, winemaker or winery owner immediately for second opinion
Wine # 9?
Brettanomyces/Dekkera Aroma: Aromas associated with Brettanomyces/Dekkera are described as barnyard, horse blanket, smoky, burnt plastic and band aid Can also produce high amounts of acetic acid
Brettanomyces/Dekkera Cause: Brettanomyces/Dekkera are yeast that enzymaticaly convert vinyl phenols derived from cinnamic acids to produce the compounds associated with these aromas being 4- ethylphenol and 4-ethylguaiacol Studies have shown it to be in the vineyards, water, soil, grape must, fermentation tanks and in barrels
Brettanomyces/Dekkera Sensory thresholds 4-ethylphenol typically found in concentrations being eight times higher then 4-ethylguaiacol 4-ethylphenol threshold 300 to 600 ng/ml 4-ethylguaiacol threshold 50 ng/ml
Brettanomyces/Dekkera Clausen (1904) reported Brettanomyces being responsible for secondary fermentation in English stock beers Therefore people who prefer this style may accept some Brett aromas and flavors in wine
Brettanomyces/Dekkera Can be viewed as a Dr. Jekyl and Mr. Hyde scenario According to Fugelsang(1997) lower concentrations of these compounds may add positive character or complexity Bordeaux wines may have this associated with them More predominate in Bordeaux wines 10 years ago Not as prominent in exported wines from Bordeaux due to other wine regions of the world viewing this as a defect
Brettanomyces/Dekkera Cause: Typically growth occurs after alcoholic fermentation during storing of wine in tank, barrel or bottle A majority of populations seen as oxidative growth in barrel aging of reds Occur in imperfections of the wood and between the staves Make it had to clean barrels efficiently to guarantee 100% sanitized
Brettanomyces/Dekkera Prevention: Brettanomyces becomes established when winery sanitation becomes lacksed Henick-Kling (2001) reports Brettanomyces sensitive to SO2, ozone, dimethyl dicarbamate and filtered at < 1 micron Grapes with rot present add at 30 50 ppm SO2
Brettanomyces/Dekkera Prevention: Early detection for 4-ethylphenol and 4- ethylguiacal can help reduce further contamination and spoilage New product from Lallemand - Chitosan (No Brett Inside) Reported to cause cell death Maintain SO2 levels at.8ppm molecular according to ph Keep barrels topped properly
Brettanomyces/Dekkera Prevention: Avoid cellar tastings when wine thief is not cleaned properly when going from barrel to barrel Recommended no cross blending with infected barrels into new or unknown barrels Sanitize all pumps, hoses and lines that have been in contact with Bretty wine Keep traffic down in winery from outside environments or sanitize footwear
Brettanomyces/Dekkera Remedy: Once aroma and flavor characteristics have been established, working with blends may be the only way to lessen the aroma However wines should not be transferred into new or uncontaminated barrels or tanks
Brettanomyces Tasting Room Information Not harmful Some customers prefer some Brett while others despise this character If suspected, notify winery tasting room manager, winemaker or owner for second sensory opinion and additional cellar information Part of winery philosophy for added complexity?
Wine # 10?
Cork Taint Aroma: Cork taint gives off aromas described as a damp wet basement, musty, moldy or even mushroom Cause: The primary compound associated with cork taint is TCA (2,4,6,-trichloroanisole)
Cork Taint Cause: The microflora of unprocessed cork consist primarily of molds including penicillium of several species In cases of wines exhibiting cork taint, Penicillium is frequently identified Microbial methylation of chlorophenols
Cork Taint Always associated with 3 circumstances Phenolic material: wood Chlorination: Chlorine based compounds Methylation: Mold Source: www.purdue.edu/research/labs/enology
Cork Taint Cause: Contamination of the cork is usually related to the cork batch Contaminant molecules infiltrate the cell structure and become trapped in the cell walls In the U.S. the incidence of cork taint is reported to range from 1 8%
Cork Taint Prevention: It is vital to develop an inspection plan to carry out quality control procedures of purchased cork The use of the Military-Standard ( Mil-spec ) system for cork quality control Inspection involves: Physical characteristics, aroma analysis and visual analysis
Cork Taint Sensory Analysis Involves Sample size Extraction media Contact time Number of analysis Distinction of normal wood and cork taint Sensory variations due to different washing mediums
Cork Taint Cork taint rejection criteria: 1) Acceptable-good, sweet, oaky cork wood, 2) Acceptable-samples with slight earthy or mushroom aromas not considered a defect 3) Unacceptable-samples with obvious TCA or other cork taint compounds
Cork Taint Tasting Room Information Not harmful If suspected, open second bottle for sensory evaluation This flaw is most likely related to individual cork batch and could be bottle dependent If second bottle exhibits same sensory flaw, confirm with tasting room manager, winemaker or winery owner May be beneficial in case of environmental TCA
Wine Flaws Tasting Room Overview Observe wine for 1) appearance 2) aroma 3) taste 4) aftertaste and 5) overall impression in performing sensory evaluation of wines prior to serving customers each day Limit perfume and cologne from affecting sensory evaluation of tasting room staff and consumers
Wine Flaws Tasting Room Overview Designate a sensory evaluation room separate from distractions and environmental smells with good incandescent lighting for proper sensory evaluation Keep training your palate by trying new varieties
Wine Flaws Tasting Room Overview Avoid varietal racism Consumers (Millenials) are willing to dry different varieties Don t turn customers away by your preferences Become familiar with key sensory descriptors for each variety Appear knowledgeable across all consumer palates Develop some winemaking knowledge and terminology
Wine Flaws Tasting Room Overview It is important to bring suspect flaws to the attention of the winery owner / winemaker since this can be a potential problem for further contamination in the cellar based on the specific defect Recognition of these flaws can also be important in control and prevention for future vintages
Wine Flaws Tasting Room Overview Tasting room staff represent the last quality control opportunity of wine prior to leaving the winery The quality of wine in the bottle directly affects the wineries perception
THANK YOU! Todd Steiner Enology Outreach Specialist OARDC Dept. Of Horticulture & Crop Science Phone: (330) 263-3881 E-mail: steiner.4@osu.edu