Yeast Assimilable Nitrogen in Grapes and Wine

Transcription

1 Yeast Assimilable Nitrogen in Grapes and Wine February 27, 2014 Amanda C. Stewart, Ph.D., Assistant Professor Department of Food Science and Technology

2 Amanda Stewart Assistant Professor, Enology and FermentaIon Research (70%), Teaching (30%) Department of Food Science and Technology Blacksburg Campus Joined Virginia Tech in August 2013

3 Virginia Wine Regions

4 Virginia Tech Enology and ViIculture Faculty/Staff/ Student Dr. Tony Wolf Dr. Amanda Stewart Title Professor of Vi1culture, Director of Winchester AREC Assistant Professor of Enology and Fermenta1on Department Hor1culture Food Science & Technology Dr. Molly Kelly Enology Extension Specialist Food Science & Technology Dr. Bruce Zoecklein Tremain Hatch Professor Emeritus, Enology and Grape Chemistry Vi1culture Research and Extension Associate Food Science & Technology Hor1culture Ken Hurley Enology Analy1cal Services Lab Food Science & Technology Ann Sandbrook Enology Analy1cal Services Lab Food Science & Technology DeAnna D APlio Graduate Student, MS Hor1culture Cain Hickey Graduate Student, PhD Hor1culture

5 Enology Research, Specific Interests Nitrogen in wine and grapes: Impact of vineyard management prac1ces on nitrogen concentra1on and composi1on in fruit Impact of nitrogen composi1on and concentra1on in fruit on wine fermenta1on and flavor (endogenous and added) Outcome: Managing nitrogen to improve wine quality, meet stylis1c goals Service lab capacity building: Support analy1cal needs of the wine industry

6 The Role of Nitrogen in Wine Making WINE STYLE STARTING MATERIAL PROCESSING PLAN FERMENTATION STRATEGY NITROGEN MANAGMENT

7 Nitrogen - not the only yeast nutrient Sugar Vitamins Thiamin Pantothenic acid Bio1n Micronutrients Zn, Mg, Mn, K, P Oxygen

8 What is Yeast Assimilable Nitrogen? (YAN) Nitrogen that can be used by wine yeast during the fermenta1on process Amino acids (primary amino nitrogen) Ammonium ions Related terms: PAN, FAN, TAN Yeast need nitrogen in addi1on to sugar for growth and metabolism

9 Why Does YAN Ma^er? Lack of YAN can lead to stuck or sluggish fermenta1on 805 mg/l 267 mg/l 402 mg/l 17 mg/l 33 mg/l 66 mg/l hours Mendes- Ferreira, A., A. Mendes- Faia, C. Leao

10 ComposiIon of YAN Ma^ers Ammonium ion nitrogen (as in DAP) Is taken up preferen1ally by yeast Can repress uptake of amino acids High cell mass early in fermenta1on deplete N early Sluggish finish, simple wines can result Amino nitrogen Ac1ve transport through cell membrane Amino acids stored in intracellular pools

11 Yeast Nutrients Primary Amino Nitrogen and NH Nitrogen (mg/l) Product Number =DAP! Measured N from NH4+ Measured - Amino Nitrogen

12 How Nitrogen Affects FermentaIon Concentra)on of YAN affects fermenta1on rate Nitrogen composi)on affects yeast metabolism, too Balance of ammonium ions and amino acids Amino acid composi1on Impacts both fermenta1on rate and aromas produced by yeast Timing of Nitrogen addi1ons ma]ers

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14 Intracellular ph RegulaIon ph ~3 3.5 H + Amino acids H + ph ~6

15 Nitrogen Transport into Yeast Cell Ethanol makes the cell membrane leaky to H + As juice becomes wine (increasing ethanol), ability to transport amino acids into the cell is impaired Amino acid addi1ons must be done early to be effec1ve ph ~3.5 H + Amino acids H + ph ~6

16 Nitrogen Dynamics Too li]le nitrogen à stuck or sluggish fermenta1on Too much DAP at the beginning may lead to high yeast cell mass, early deple1on of nitrogen, and stuck fermenta1on Amino acids added late in fermenta1on will not be u1lized by yeast Understand nitrogen strategy and select products accordingly Or not

17 How much YAN is needed? Brix of Must Target YAN ConcentraIon mgn/l mgn/l mgn/l mgn/l Bisson and Butzke, 2000

18 YAN surveys West Coast Vi)s vinifera, US 40 mg/l to 559 mg/l (Butzke, 1998) 25 mg/l to 336 mg/l (Hagen et al. 2008) No survey of Eastern US No survey of interspecific hybrids or Vi)s labrusca

19 Wine Grapes for the Eastern US 90% of the world s grapes are Vi)s vinifera Problems for Vi)s vinifera in Eastern US Powdery Mildew, Downy Mildew Cold hardiness Pierce s Disease Bordelon, 2012, FS 470 class lecture, Vi)culture

20 Wine Grapes for the Eastern US Breeding against abio1c stress Breeding against pests and diseases

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22 Chemistry of Hybrids vs. Vi)s vinifera Known differences in: Disease resistance Acid, ph, Brix Phenolic composiion Flavor, varietal character What about nitrogen? Nitrogen concentraion and composiion impacts: FermentaIon rate Wine aroma and flavor

23 YAN Survey Collaborators Collaborator LocaIon AffiliaIon Anna Katharine Mansfield Geneva, NY Cornell University KaIe Cook Minneapolis, MN University of Minnesota Jennie Savits Ames, IA Iowa State University Brent Trela Lubbock, TX Texas Tech Andrew Perry, Brian Hosmer Traverse City, MI Leo Foot Charley Winery Nancie Corum- Oxley Paw Paw, MI St. Julian Winery Andrew Meggit St. James, MO St. James Winery John Metzcar Bloomington, IN Oliver Winery Keith Striegler Missouri Flint Ridge Winegrowing Jeanne Burgess Clermont, FL Lakeridge Winery (Stewart, 2013)

24 YAN Data Points by State State n AR 10 CA 51 FL 179 IA 71 IL 4 IN 327 MI 221 MN 171 MO 437 NY 193 SD 28 WA 25 total 1717 (Stewart, 2013)

25 YAN Survey Results: Average by Variety N = 1,451 Years: varieies Hybrids developed by U of MN V. rotundifolia, Florida (Stewart, 2013)

26 YAN Survey Results by Species (including APPLE) YAN (mg N/L) (Stewart, 2013) Hybrid ViIs aesivalis ViIs labrusca ViIs rotundifolia ViIs vinifera Apple

27 YAN by State YAN (mg/l) (Stewart, 2013) AR CA FL IA IL IN MI MN MO NY SD WA

28 YAN by Year YAN (mg/l) (Stewart, 2013)

29 600 Frontenac YAN (mg/l) IA IL IN MI MN NY SD (Stewart, 2013)

30 250 Cabernet Franc 200 YAN (mg/l) IN MI NY (Stewart, 2013)

31 250 Tramine^e 200 YAN (mg/l) IN MI MO NY (Stewart, 2013)

32 300 Riesling 250 YAN (mg/l) CA IN MI MN NY WA (Stewart, 2013)

33 Factors AffecIng YAN ConcentraIon and ComposiIon Nitrogen applica1ons Soil Foliar Soil water holding capacity Rainfall Cul1var Cover crops? Rootstock?

34 Bisson and Butzke, 2000

35 ComposiIon of YAN Ammonium ions and free amino acids Arginine and proline are the most prevalent amino acids in Vi#s vinifera wine grapes What about other grape species? Vi#s labrusca? Vi#s rotundifolia? Hybrids?

36 Amino Acid Profiles for Vitis vinifera SW Purdue Ag Center Vincennes, IN Washington Spayd et al (Stewart, 2013)

37 (Stewart, 2013) Vi)s labrusca hybrids

38 White Hybrid Varieties Developed by Cornell (Stewart, 2013)

39 Red Hybrid Varieties Developed by Cornell (Stewart, 2013)

40 (Stewart, 2013) Blanc du Bois

41 Vi)s rotundifolia (Muscadine) (Stewart, 2013)

42 So, HOW MUCH YAN IS NEEDED? Follow current recommenda1ons, based on Brix Balance of inorganic and organic nitrogen ALWAYS consider yeast strain requirements Guidelines require further inves1ga1on YAN for a given cul1var and yeast strain combina1on How much is too much? Balance of NH3+ and amino nitrogen? Effect on typicity??? Tailored strategies probably required

43 Determine AddiIon Rate First determine your target Measure YAN in star1ng material (juice or must) Subtract to determine actual deficiency Then determine how much to add Consider YAN contribu1on of nutrient product Understand DAP vs. Primary Amino Nitrogen Inorganic vs. Organic

44 How can I measure YAN? 2 measurements using Spectrophotometer Primary Amino Nitrogen NOPA Assay (Spectrophotometer) Ammonium Ion Concentra1on Enzyma1c kit (spectrophotometer) Ammonium ion probe (connect to ph meter) Formol 1tra1on using formaldehyde Not recommended due to waste disposal and safety issues Contract analysis lab

45 Primary Amino Nitrogen Primary Amino Nitrogen by NOPA Assay Chemical deriva1za1on of free amino acids (except proline) Change in absorbance measured by spectrophotometer Commercial kits available Or make reagents in- house (UC Davis Extension publica1on)

46 Ammonium Ion Assay Enzyma1c assay Commercial kits available Ammonium Ion probe requires careful calibra1on, but is a good op1on as well

47 When Can I Measure YAN? Photo credit, C. Butzke

48 YAN (mg/l) (Stewart, 2013) Interspecific Hybrids, Cornell VarieIes Sampling Point Noiret Cayuga White Corot Noir

49 YAN (mg/l) Interspecific Hybrids, University of Minnesota VarieIes Frontenac Gris LaCrescent Frontenac Marque]e MN Sampling Point (Stewart, 2013)

50 Interspecific Hybrids, Cornell VarieIes 500 YAN (mg/l) Sampling Point Vignoles Noiret Cayuga White Corot Noir NY Chardonel Valvin Muscat Tramine]e (Stewart, 2013)

51 What can I do about YAN? Be aware of the role of nitrogen in fermenta1on Be aware of YAN in your star1ng material Varies by cul1var, growing season, vineyard mgmt prac1ce Highly variable, need to measure each lot Add yeast nutrients DAP Complex yeast nutrients Or not

52 Photo credit, C. Butzke

53 ImplicaIons of Excess YAN? Promotes undesired microbial growth Flavor enhancing, savory/umami notes Maillard reacions during wine aging Amino acid + sugar à flavor acive compounds at µg/l Grilled meat, roasted, charred notes Alter varietal character? (Bea^y and Butzke, 2013)

54 Summary Yeast Assimilable Nitrogen (YAN) is required for successful fermenta1on YAN is variable in different star1ng material Understand nutrient products and make targeted addi1ons Timing of addi1ons ma]ers Recommenda1ons need refinement by cul1var and yeast strain tailored to overall stylis1c goals and fermenta1on strategy

55 Nancie Oxley Linda Jones Paul Jenkins Barb Mutch Brian Hosmer Drew Perry Dr. Greg Peck Dr. Tony Wolf Dr. Molly Kelly Dr. Bruce Zoecklein Dr. Joe Marcy Dr. Chris1an Butzke Dr. Bruce Bordelon Acknowledgments

56 THANK YOU!