MALOLACTIC BACTERIA

P.O. BOX 4559 • 2220 Pine View Way Petaluma, CA Tel: (707) 765-6666 • Fax: (707) 765-6674 • www.scottlab.com950 Brock Road South • Unit 1 • Pickering, ON • L1W2A1 • Canada • Tel: (905) 839-9463 • Fax: (905) 839-0738 • www.scottlabsltd.com

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MALOLACTIC FERMENTATION

EVALUATING CONDITIONS

Malolactic fermentation (MLF) not only converts malic acid to lactic acid, but also has a direct impact on wine quality. Uncon-trolled spontaneous malolactic fermentations or wild lactic acid bacteria can result in diminished varietal and fruit �avors, reduced esters, masked aromas and o�-characters. The importance of choosing a selected strain has increased due to evolving winemaking preferences (e.g. higher pH levels, lower S02, higher alcohol, etc.), as well as concerns such as biogenic amines. The use of selected malolactic strains can contribute postitively to wines while minimizing risks.

It is very important to know the status of the wine prior to inoculating with ML bacteria. Analyze the wine for pH, S02, VA, malic acid and alcohol level. Note: The limits shown on the chart below are individually stressful. In combination, stresses are increased. Other aspects such as nutrition can also be critical.

MLF FEASIBILITY

Predicting the feasibility of malolactic fermentation is very important, since many conditions in�uence the activity of ML bacteria in wine. MLF that is spontaneously triggered too early or too late can result in loss of wine quality. The key points to consider are: interactions between pH and S02, alcohol and temperature interactions, the initial malic content, the development of alcoholic fermentation, and the timing of inoculation. The chart below can help evaluate the conditions for MLF in a speci�c wine.

CO-INOCULATION

Inoculation of malolactic bacteria in the must, together with or shortly after yeast inoculation (co-inoculation) has been proposed as an alternative inoculation technique in low pH wines without increasing volatile acidity. Co-inoculation of MLB with yeast has also been advocated for red wines, or potential high alcohol wines, giving the bacteria a better chance to grow and acclimate in the absence of ethanol.

Early co-inoculation with commercial MLF starter cultures 24 hours after the yeast, proved very e�cient in various studies. Co-inoculation �nished alcoholic fermentation and malolactic fermentation within a short time frame, which can be positively applied to cellar productivity. All combinations of this co-inoculation strategy produced less biogenic amines than other treatments. Co-inoculating with 1-Step cultures under high pH conditions can be used with a short rehydration step in water (with the activator added for best results).

When using appropriate yeast and MLB combinations, and applying best manufacturing practices, co-inoculation of bacteria with yeast did not a�ect AF kinetics. No signi�cant di�erence in the volatile acidity levels was found, even under high pH red wine conditions.*

*Krieger-Weber, S. 2012. “Economic Yeast and Malolactic Bacteria Co-Inoculation in Red Wine.”

<13 - Favorable 13-22 - Mediocre 23-40 - Di�cult >40 - Extreme

Choose the bacteria adapted to your wine. A speci�c bacteria nutrient may be necessary.

Give preference to a 1-STEP® bacteria adapted to your wine. Adjust conditions to optimize MLF: temperature, bacterial nutrition, etc.

Run a quick test or consult a technical representative. Decrease the obstacles before inoculating: blending, deacidi�cation, temperature, nutrition.

Pay attention to the development of indigenous �ora (Brettanomyces, contaminating bacteria, etc.) Inoculate rapidly with selected bacteria.

1-STEP CULTURES

1-Step® cultures are new and improved versions of an old concept. The purpose is to provide winemakers with a product which combines the economy and activity of standard strains with a degree of the convenience associated with the direct inoculation strains. In lieu of direct inoculation or prolonged build-up, a simple 18-24 hour acclimitization step is required using a culture of Oenococcus oeni and an activator (included in the kits). 1-Step cultures are good choices where e�ciency and cost management are essential.

1-Step Cultures Available:• 1-Step Alpha - Adapted to high alcohol, enhances mouthfeel, considered an “All-Arounder”• 1-Step VP41 - Adapted to high alcohol, low diacetyl producer

DIRECT INOCULATION CULTURES

Since wine environments can be hostile, direct inoculation starter cultures must be conditioned to this environment during their production. The direct inoculation process was developed to prepared the cell membrane in advance for these di�cult condi-tions. The result is highly active cultures which are ready for easy and quick inoculation of wine. Proper nutrition can help enhance performance, especially in a harsh environment. All Lallemand direct inoculation strains are produced with the MBR process. The MBR form of malolactic bacteria represents a Lallemand acclimitization process that stresses the bacteria, enabling it to withstand the rigors of direct inoculation. The conditioned MBR bacteria can conduct a more reliable MLF.

Direct Inoculation Cultures Available:• Alpha - Adapted to high alcohol, enhances mouthfeel, considered an “All-Arounder”• Beta - Enhances berry fruit in co-inoculation, high diacetyl producer in sequential inoculation• ICV Elios 1 - Adapted to high alcohol, contributes to tannin and mouthfeel intensity• MBR 31 - Adapted to low pH, enhances fruit character• PN4 - Adapted to di�cult conditions, high diacetyl producer, considered “The Rocket”• VP41 - Adapted to high alcohol, low diacetyl producer

P.O. BOX 4559 • 2220 Pine View Way Petalum a, CA Tel: (707) 765-6666 • Fax: (707) 765-6674 • www.scottlab.com950 Brock Road South • Unit 1 • Pickering , ON • L1W2A 1 • Canada • Tel: (905) 839-9463 • Fax: (905) 839-0738 • www.scottlabsltd.com

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FREQUENTLY ASKED QUESTIONS

Check the wine parameters (free and total S02, alcohol, pH, VA, malic acid and temperature) to determine if there is an obvious reason the fermentation is not completing. Pesticide and fungicide residue, juice concentrates and preservatives in juice or wine can also inhibit malolactic bacteria.

S02 www.scottlab.com for more information.

How do I choose the correct strain of bacteria for my wine?

S02 levels, pH, alcohol, temperature constraints, as well as malic acid concentration.

USING MLF TO DETERMINE WINE STYLE

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Certain strains of O. oeni consistenly enhance the fruity-berry characters in red wine.

What sensory outcomes can MLF regulate?Sensory impressions such as buttery, vanilla-like, nutty, spicy, fruity, vegetative, toasty, fuller and rounder are used to describe

MLF and winemaking variables which can be used to modulate sensory attributes: • Choice of bacterial strain • Timing of MLF inoculation • Sequential (after alcoholic fermentation) • Simultaneous with yeast (co-inoculation)

Sensory attributes which can be modulated via MLF and bacterial metabolism: • Buttery character • Fruity character • Mouthfeel

Diacetyl Concentration During WinemakingLess More

VP41 Elios 1 Alpha Lalvin 31 Beta PN4Only attacks citric acid after completion of malic acid

Medium producer Medium producer Medium to low producer

High producer when used in sequential inoculation

Early attack of citric acid

O-MegaVery low producer