1. Grape “Quality” Optimizing the Quality of Grape Cultivars By: Paul Gospodarczyk Des Moines Area Community College ptgospodarczyk@dmacc.edu paul@todayswineprofessional.com

2. What is “Quality?” Nobody knows! Easy to define what quality is NOT Hard to define what it IS Grapes are at the highest potential quality—winemakers maintain or detract from that potential

3. Most important factor: How does the wine TASTE? Nothing else matters.

4. ECON 101 Supply Demand Supply vs. Demand

5. ECON 101 Supply Demand Commodity Market

6. ECON 101 Supply Demand Specialty Market

7. Communication: -It’s up to you! -Push the winemaker

8. Goals Today Investigate attributes worth talking about Understand the importance of these attributes

9. Some basics…

10. Grape Ripening Time Amount Acid Sugar

11. Grape Ripening Time Amount Acid Sugar 1

12. Grape Ripening Time Amount Acid Sugar 12

13. Ripeness Effects Flavor Acid –pH –TA Color –Hue –Intensity

14. Ripening and Flavor Time Amount Acid Sugar 12 Flavor change!

15. Acid Expression Paradox of acid expression: –Titratable acidity: grams per Liter –pH: inverse logarithmic representation of the hydrogen proton concentration

16. TA vs pH Acid Expression

17. Ripening and Hue Low pH, 20-25% High pH, 10% Flavylium State Quinoidal State Most Anthocyanins colorless at wine pH

18. Ripening and Color Intensity Rim Variation I wanted to see this in a lab…

19. Wine A: High Color Intensity

20. Wine B: Low Color Intensity

21. Ripening and Color Intensity Wine A; Hue =.6; Intensity = 3 Wine B; Hue =.9; Intensity = 1.8

22. White Wine Tasting: Investigating Effect of TA Don’t finish the samples!

23. Monitoring Fruit It’s a sample! Striving for even ripening: –Dormant season pruning –Shoot positioning –Green harvest

25. Hungry? Want to use this plate?

26. Sanitation vs. Sterilization

27. Sulfur Citric Sanitation Requires: –200 ppm Sulfur; 2-3 tablespoons –< 3.0 pH; couple scoops Buying Potassium Metabisulfite Efficacy

28. Hungry?

29. Sulfur Dioxide Additions Inhibits enzymatic oxidation –Polyphenoloxidase –Laccase

30. Sulfur Dioxide Additions Calculating sulfur dioxide –Based on JUICE YIELD –Average 150 gallons juice/ton –Clean Fruit 30 ppm = 30 grams (1.06 oz.) –Rotten Fruit 75 ppm = 74 grams (2.65 oz.)

31. Hungry?

32. Lady Bugs Green, peas, peanuts, gross mushrooms Identification threshold is at PPT –1 trillion seconds = 31,546 years

33. Spray Records

34. Cellar Handling Chaptalization –$.75/pound C&H –$9.39/T ($.06/gal.) to raise 1 Brix Amelioration

35. Red Wine Tasting: Investigating Effect of TA Don’t finish the samples!

36. Correlation Comparison of 2 independent data sets R value explains variability –Low ‘r’ = no relationship –High ‘r’ = possible relationship (r > 85%) –R =.65 means 65% of variability is accounted for CAUSATION is not implied

37. Correlation Shark Attacks Ice Cream Sales R =.24 R squared =.0576

38. Correlation Shark Attacks Ice Cream Sales R =.89 R squared =.79 Not Causal!

39. Searching for a correlation… A model to predict ‘quality’ wines

40. Frontenac Project 11 Iowa Frontenac wines Chemical analysis performed in triplicate Sensory data from 3 panelists –Majority of panelists had completed VIN 150 sensory training –Assigned No medal, Bronze, Silver, and Gold

41. Frontenac Project R = 66.5% R = 60.6% Percentage

42. Frontenac Project

44. r = 68.3% r = 60 % r = 47% r = 63.5% r = 58.5%

45. Frontenac Project r = 78.8% Descriptor Frequency Intensity Rating

46. Red Wine Tasting: Investigating Effect of TA on Tannin Perception

47. Obviously, quality indicators of wine will be multivariate…

48. Suppleness Index Suppleness aka richness Relationship of alcohol, tannin, and acid Review: –Alcohol measured in percent –Acid measured in grams/liter In France it’s calculated as ‘Sulfuric Acid’ and not ‘Tartaric Acid’ –Tannin measured in g/L

49. Suppleness Index Alcohol – (Acid + Tannin) = Suppleness

50. Suppleness Index The equation: ETOH% - (T.A. + Tannin) = Suppleness > 5 = supple wine

51. Suppleness Index Cabernet examples: Wine 1: 12% Alc - (3.6 TA + 1.8 Tannin) = 6.6 Supple Wine 2: 10.5% Alc – (4.2 TA + 2.4 Tannin) = 3.9 Not Supple

52. Suppleness Index Frontenac examples: Sample 743: 12.73%–(7.45 TA +.5 Tannin) = 5.78 Sample 291: 11.5% – (6.6 TA +.5 Tannin) = 4.4 Sample 238: 11.9% – (16.2 TA +.5 Tannin) = -4.8

53. Correlation: Suppleness and Numeric Award: r =.52; 52% of variability accounted for Amelioration?!

54. Frontenac—Ordered by Suppleness SampleSupple (.5 tan.)AwardAward Num. 7435.78Gold7.11 2725.67Silver5.26 2915.40Silver5.18 7875.03Silver4.58 6624.97Silver5.26 5884.78Silver5.38 7814.77No Medal1.93 3744.40Silver4.93 4534.20Gold6.83 611.83Bronze3.03 238-3.82No Medal2.86 1. No 2. B- 3. B 4. B+ 5. S- 6. S 7. S+ 8. G

55. Suppleness: Key Lessons Acid reinforces bitter/astringent flavors High acid and high tannin are not good High alcohol and low acid required for elevated tannin levels

56. Suppleness in Perspective: Developed by Peynaud and Gayon Bordeaux wine production in the 50’s and 60’s High suppleness = riper fruit

57. Who is Hungry? …because lunch is in 15 minutes! Paul Gospodarczyk Des Moines Area Community College ptgospodarczyk@dmacc.edu paul@todayswineprofessional.com