Todd Steiner Enology Program Manager & Outreach Specialist Department of Horticulture & Crop Science The Ohio State University/OARDC Wooster, OH

Transcription

1 Todd Steiner Enology Program Manager & Outreach Specialist Department of Horticulture & Crop Science The Ohio State University/OARDC Wooster, OH 44691

2 THANK YOU! 2014 Michigan Annual Wine Conference Conference Organizing Committee Nancy Oxley Initial Contact Linda Jones Barb Mutch

3 GO BUCKEYES!

4 Wine # 1 White Wine Control: 2011 Pinot Gris

5 Wine # 2?

6 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

7 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

8 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

9 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

10 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

11 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 ppm SO 2

12 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

13 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

14 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

15 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

16 Wine # 3?

17 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)

18 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

19 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

20 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

21 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

22 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

23 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)

24 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

25 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

26 Wine # 4?

27 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

28 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

29 Addition of SO 2 to obtain.8 ppm molecular) ph Free SO 2 ph Free SO Source: C. Smith, Enology Briefs, Feb/March, 1982, Univ.. of Calif.., Davis

30 Free SO 2 (mg/l) Other role of SO 2 : Molecular SO 2 as anti-microbial ppm molecular 0.8 ppm molecular 0.6 ppm molecular Source: Dr. Gavin Sacks, 2014 Ohio Grape and Wine Conference Molecular SO 2 can be calculated from ph and free SO ppm (mg/l) molecular SO 2 typical rec for dry wines 2 ppm is approximate sensory threshold of molecular SO 2 ph

31 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)

32 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

33 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

34 Wine # 5?

35 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

36 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

37 Hydrogen Sulfide Factors responsible for H 2 S production High concentrations of insoluble solids Increased must ph Higher fermentation temperatures

38 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

39 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

40 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

41 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

42 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!

43 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

44 Wine # 6 Red Wine Control: 2010 Cabernet Franc Blend

45 Wine # 7?

46 Ethyl Acetate Aroma: Wines high in ethyl acetate express aromas of nail polish, airplane glue, varnish etc. Sensory threshold reported at mg/l Lesser concentrations can enhance wine complexity being an aromatic ester and aid in sweetness and richness on the palate

47 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

48 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

49 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

50 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

51 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

52 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

53 Wine # 8?

54 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

55 Geranium Taint Factors contributing to geranium taint Wines with some residual sugar may have sorbic acid added to prevent re-fermentation by yeast

56 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

57 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

58 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

59 Wine # 9?

60 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

61 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

62 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

63 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

64 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

65 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

66 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 ppm SO2

67 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

68 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

69 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

70 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?

71 Wine # 10?

72 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)

73 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

74 Cork Taint Always associated with 3 circumstances Phenolic material: wood Chlorination: Chlorine based compounds Methylation: Mold Source:

75 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%

76 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

77 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

78 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

79 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

80 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

81 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

82 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

83 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

84 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

85 THANK YOU! Todd Steiner Enology Outreach Specialist OARDC Dept. Of Horticulture & Crop Science Phone: (330)