When life throws you lemons, how new innovations and good bacteria selection can help tame the acidity in cool climate wines

Transcription

1 When life throws you lemons, how new innovations and good bacteria selection can help tame the acidity in cool climate wines Dr. Sibylle Krieger-Weber R&D Bacteria, Lallemand Germany VitiNord August 2 nd 2018 UNIVERSITY COPENHAGEN 1

2 Impact factors MLF in Cool Climate Wines Starter cultures for malolactic fermentation under low ph conditions An inovative approach to manage acidity in cool climate white wines 4

3 Electronic Tools Focus: ipad / iphone APP Electronic Wheels

4 SO 2 and MLF SO2 moléculaire (mg/l) The molecular SO 2 molecular is the most active form of the sulfuric acid with the highest antimicrobial activity. Molecular SO 2 = free SO 2 / ( 10 (ph ) + 1 ) SO2 libre : 10mg/l - 18 C ph 0 % v/v 13 % v/v SO2 (mg/l) ) The molecular SO 2 increases with a decrease in ph and increase of temperature and/or alcohol The lethal level for wine bacteria: 0.3 mg/l- 0.5 mg/l. molecular SO2 (mg/l) at 18⁰C added free ph 3.0 ph 3.1 ph 3.2 ph 3.3 ph

5 Malic acid tolerance / Lactic acid sensitivity Factors that impact MLF Easy Moderate Difficult Extreme Initial level of malic acid (g/l) or or >7 or <0.5 Organic Acids From practical experience: - wines with L-malic acid levels below 1 g/l not as conducive to MLF as are wines with L-malic acid concentrations between 2 and 4 g/l. - wines with levels of L-malic acid above 5 g/l start L-malic acid degradation, but do not always go to completion. Inhibition of the bacteria by increasing concentrations of L-lactic acid derived from the MLF itself? Acidification with the organic acids lactic acid, L(-) or DL malic acid, L(+) tartaric acid and citric acid is authorized by OIV and in many wine regions. => In collaboration with Lallemand, IFV (V. Gerbaux) in France has studied the influence of organic acid additions on MLF.

6 Impact of initial malic acid content Chardonnay 12.5%v/v ph=3.25 Malic acid = 2.6g/L Temp.= 16 C Duration of MLF of course increases with malic acid content. However: - Same latency phase duration for all conditions. - Speed of malic acid degradation increases with malic acid content. - Some strains little affected by an increase of malic acid content. Addition of D-malic acid (D,L malic acid) has no noticeable effect on MLF

7 Impact of addition of L-lactic acid before MLF Chardonnay 12.5%v/v ph=3.25 Malic acid = 2.6g/L Temp.= 16 C Bacteria population - Alpha 1,0E+07 log cfu/ml 1,0E+06 1,0E+05 Lactic acid 0 Lactic acid 1.5 Lactic acid 3.0 1,0E Time (days) Strong effect of lactic acid addition on bacteria population and MLF duration. Addition of 1.5g/L highly increases the time to achieve MLF. Addition of 3g/L induces a high loss of viability which leads to stuck MLF. Alpha seems to be highly sensitive.

8 Yeast Impact on MLF Study of yeast-bacteria interactions: a complex topic because of the number of parameters to take into account. Increasing knowledge of yeast strains properties help us to better classify yeast depending on their compatibility with MLF. SO 2 production by yeast is still of course a key parameter because SO 2 is one of the major MLF inhibitors. Best compatible are yeast strain with a moderate fermentation rate, low to medium nitrogen demand and no SO 2 production

9 MLF in Cool Climate Wines: Working at the Limit Impact factors Starter cultures for malolactic fermentation under low ph conditions An inovative approach to manage acidity in cool climate white wines 4

10 Understanding the biodiversity Grape Must AF MLF Aging Lactobacillus plantarum Lactobacillus mali Lactobacillus kefiri Lactobacillus lindneri Lactobacillus brevis Lactobacillus buchneri Lactobacillus kunkeei Lactococcus lactis Enterococcus faecium Enterococcus avium Enterococcus durans Enterococcus hermanniensis Leuconostoc mesenteroïdes Pediococcus parvulus Pediococcus damnosus (Oenococcus oeni) L. plantarum L. sanfrancisensis L. casei P. parvulus L. hilgardii... O. oeni 0-10% L. plantarum P. parvulus L. hilgardii O. oeni % (Lactobacilli) (pediococci) O. oeni Why O. oeni? The main LAB species during MLF Lactobacilli Pediococci (O. oeni) 10

11 Understanding the biodiversity Why O. oeni? O. oeni is not the good species in wine O. oeni is the best-adapted species Bacteria process of production plays a KEY role in resistance

12 Understanding the biodiversity 16 strains: - 4/ Burgundi white wine - 4/ Burgundi red wine - 4/cider - 4/ O. kitaharae ph Ethanol ph tolerance Cider > B white> B red > O. kitaharae % Ethanol tolerance B red = B white > cider > O. kitaharae 12

13 Selected LAB starter cultures for MLF Build-up-cultures (with reactivation): - Standard - Acidophil + Cultures with acclimatization step: 1-Step Cultures for direct inoculation: MBR

14 MLF in Cool Climate Wines: Working at the Limit Impact factors Starter cultures for malolactic fermentation under low ph conditions An inovativeapproach to manage acidity in cool climate white wines 4

15 Inoculation Regime Co-inoculation is the practice of inoculating selected wine bacteria early in the winemaking process.

16 Co inoculation under low ph conditions White wines Rosé wines young fresh red wines Advantages Adaption to limiting wine conditions Acclimatization throughout alcoholic fermentation Shorten length of AF+MLF Diacetyl management Can enhance fresh fruit characters No risk of VA production

17 A new species: Lactobacillus plantarum

18 A new approach Developed by a new production process that optimizes the activity of the malolactic enzyme system of the bacterial culture. This high activity of malolactic enzyme reduces the lag phase and allows a very quick malolactic fermentation Fast malic acid degradation due to a non-proliferating LAB biomass = MLF can be achieved during AF in high ph red wines Important malolactic enzyme pool Wine can be stabilized right after AF

19 ML PRIME IN WHITE WINE NEW APPLICATION partial MLF on whites Co-inoculation or post AF inoculation Partial Malic acid degradation : 20% (limiting conditions) - 90% (easier conditions) Window of Application ph: 3.05 Malic acid content: 8 g/l Temperature range: from 17 C to 22 C Total SO2 tolerance in must up to 5 g/hl Free SO2 tolerance in wines: less than 10 mg/l Experience : Austria / Alsace/ Loire Valley / Germany

20 ML Prime on white wines partial MLF AS17-38: partial or total desacidification on white wine(france) Objective: Evaluate the capacity of ML Prime to degrade malic acid in low ph/high malic acid white wine conditions, even partially, in the final wine. Compare with chemical desacidification(200g/hl K-bicarbonate) Initial wine analysis Gros Manseng post AF inoculation Initial wine post AF analysis Total acidity [g/l tartaric] 8,7 ph 3,36 Free SO2[mg/l] 11 Total SO2 [mg/l] 87 Tartaric acid [g/l] 1.1 Malic acid[g/l] 6,8 Glucose/Fructose [g/l] 2,0 Volatile acidity [g/l acetic acid] 0,36 Lactic acid [g/l] 0,0 Alcohol [% Vol] 12,3 They choose 100g/hL K-bicarbonate for the chemical deacidification

21 Experimental Set-up 3 tanks same wine end of AF: Comparison chemical treatment vs. biological treatments Dosage SO2, : tartaric, malic, lacticacids, ph, AT. A A : Biological deacification ML PRIME 10g/hL Constant temperature C. B B : Biological deacification ML PRIME 20g/hL Constant temperature C. C C : chemical deacidification 100 g/hl Potasium bicarbonate Check kineticsof MLF Dosage SO 2 : Tartaric, malic, lacticacids, ph, TA

22 ML Prime on white wines: partial MLF post AF inoculation - Temperature 20 C. Chemical composition after 10 days of ML Prime contact time: Treatmen t TA [g/l TH2] ph Free SO2 [mg/l] Total SO2 [mg/l] Tartaric Acid [g/l] Malic acid [g/l] Glucose/Fruc tose [g/l] VA [g/l acetic acid] Alcohol [% Vol] ML Prime 10g/hL MLPrime 20 g/hl 7,3 3, ,1 3,0 2,05 0,39 12,6 6,1 3, ,1 0,6 2,06 0,39 12,6 Control 8,7 3, ,4 2,07 0,37 12,6 Chemical deacidific ation 7,6 3, ,5 6,8 2,06 0,37 12,5 ML Primeat 10g/hL=> 56% of malic acid degradation ML Prime at 20g/hL=> 91% of malic acid degradation Better Deacidificationthan chemical compounds The sensory quality of the wines treated with ML Prime have really higher quality : more fruit expression more balance

23 Varietal: Chenin blanc / co-inoculation / direct inoculation / normal dosage Must Pot. Alc. (%vol) 11,1 Sugar (g/l) 187 TA (g/l) 6,6 ph initial 3,05 malic acid (g/l) 7,3 Malic Acid (g/l) Nitrogen (mg/l) Kinetics of malic acid degradation depending of the initial ph (intial malic acid 7,3 g/l) CHE1 (ph3.1) CHE2 (ph3.2) CHE3 (ph3.3) CHE4 (ph3.4) CHE5 (ph3.5) Time (days)) - At thishigh initial malicacidcontent - Maximum degradation3 g/l 3,5 g/l of malicacid(ca. 40%)

24 PRACTICAL CONSIDERATIONS Selected wine lactic acid bacteria adapted low ph wines are suited for vintages with high acidity and low phes A small de-acidification in the range of 1g can support the following MLF Co-inoculation can reduce the time of MLF and help wine bacteria acclimatization Careful selection of the active dry yeast strain, avoid SO 2 -producers, and respect a good yeast & bacteria nutrition Reflect about your SO 2 additions in case of low ph and healthy grapes less SO 2 is needed to have a good microbial security New approach L. plantarum for a rapid partial malic acid degradation

25 THANK YOU! For your attention & questions