Choosing ML Bacteria Strains for Wine Sensory Impact
Last updated: 7/2021
Applies to: Winemakers looking to learn how bacteria strain choice can influence wine sensory and compare bacteria strains sold by Scott Laboratories.
MLF and Wine Sensory
Malolactic fermentation (MLF) is more than a simple conversion of malic acid to lactic acid. Recent research, specifically trials done at The Australian Wine Research Institute, show that in addition to reducing acidity and stabilizing wine, malolactic fermentation can affect wine sensory characteristics in a positive way. With this information, strain choice of malolactic bacteria has become an exciting tool for winemakers to influence wine aromas and drive wine style. MLF is associated with a broad range of other metabolic processes that impact a wine’s sensory profile and common terms used to describe the effect on wine flavor are fruity, spicy, toasty, nutty and buttery.
There are 2 major variables that affect the sensory impact of MLF
- Timing of MLF inoculation
- Strain Choice
The timing of malolactic inoculation primarily impacts fruit expression and diacetyl production. Malolactic bacteria can be added just after the yeast so that the alcoholic and malolactic fermentation (MLF) occur simultaneously. This co-fermentation is referred to as co-inoculation. A co-inoculation with yeast and ML bacteria will result in wines that are fresh and fruity with very little diacetyl (butter) character. Alternatively, malolactic bacteria can be added towards the end or at the end of alcoholic fermentation. This is referred to as sequential inoculation. Sequential inoculation wine may have higher levels of buttery character (especially when using certain ML strains) and enhanced aromatic complexity.
We’ve been able to characterize the sensory impact of each of the strains carried by Scott Laboratories and they're each discussed in the next section of this article.
Bacteria Choosing Guide
Co-inoculation strain of Oenococcus oeni for fresh and fruit-forward wines (White, Red, Rosé)
ENOFERM BETA CO-INOC™ is recommended for fresh, fruit-forward red and white wines. This Oenococcus oeni strain was specifically selected by Lallemand Oenology for reliable malic acid consumption when added to juice/must 24-48 hours after yeast inoculation. BETA CO-INOC is not recommended for use in a sequential MLF.
For more information on how a co-inoculation can affect the production of diacetyl, read our article on the subject by clicking below:
Oenococcus oeni for aroma complexity and mouthfeel enhancement (White, Red)
ENOFERM ALPHA™ contributes to wine aroma complexity and mouthfeel in red and white wines. White wines have increased levels of pear, apricot and pineapple aromas. Red wines have more berry, cherry and plum aromas with a softer, rounder mouthfeel and decreased green and vegetative characters.
Oenococcus oeni for increased diacetyl production, fruit and floral expression, and tannin integration (White, Red)
ENOFERM BETA™ preserves and enhances varietal aromas, increases volume and softness, and can impact the diacetyl levels of wines. In white wines buttery aromas and flavors are produced. If the wine is left on the lees, the buttery notes are decreased and tropical fruit aromas like pineapple and mango are evident. In red wines, BETA is used to support tannin structure and red fruit flavors. Compounds such as beta-damascenone and beta-ionone are increased, contributing floral and berry notes.
Oenococcus oeni for enhanced fresh fruit, spice and tannin integration (Red)
LALVIN ELIOS 1™ is suited for Mediterranean, Rhône style and other warm climate red wines for enhanced red fruit aromas, spice, and tannin intensity. Wines have an integrated mouthfeel with good mid-palate intensity, decreased drying sensations and increased freshness. The perception of green and vegetative characters is reduced.
LALVIN (MBR) 31™
Oenococcus oeni for balanced sensory and color stability in low pH wine and low temperature ferments (White, Red, Fruit, Cider)
LALVIN 31™ is suitable for cool climate red and white wines, enhancing varietal characters, fruit flavors and promoting color stability. In white wines, it adds complexity due to its light buttery flavor. With lees contact the buttery notes decrease, elevating fruit flavors and mineral notes. In red wines, dark berry fruit flavors, color stability and mouthfeel are increased. Wines made using LALVIN 31 have good body and length.
Oenococcus oeni strain for strong fermentation, freshness and fruit expression (White, Red)
O-MEGA™ is suitable for fresh fruit expression in high maturity grapes. O-MEGA balances and complements ripe flavors in white wines by bringing freshness, mineral and citrus notes. In red wines it highlights red and dark berries like redcurrant, strawberry, blackcurrant and blackberry. Using this bacteria strain in red wines may help stabilize color due to its slow degradation of acetaldehyde. Although recommended for ripe grapes it does well in cold climate Pinot noirs.
O-MEGA has a late degradation of citric acid resulting in very low diacetyl and low volatile acidity. It should not be used in wine with herbaceous or vegetative notes as these will be amplified.
Oenococcus oeni for fast fermentation with enhanced spice, fruit and mouthfeel (Red, White)
PN 4™ is equally suited to red and white winemaking where it contributes to aromatic complexity, mouthfeel and balance. Red wines are described as having increased spiciness with elevated notes of nutmeg, licorice and pepper. General fruit notes of plum, cherry and berry are increased, structure is enhanced and herbaceousness masked.
In tank fermented white wines with minimal lees contact, varietal expression is increased. In barrel fermented white wines notes of honey and butter (diacetyl) are reported, mouthfeel is full and creamy and oak is well-integrated.
Oenococcus oeni for silky mouthfeel, aromatic balance and good oak integration (Red)
LALVIN SILKA™ is recognized for its positive impact on aromas and mouthfeel. SILKA accentuates aromas of chocolate, vanilla, and toast, balanced by aromas and flavors of red currant, blackberry and cherry. This malolactic bacteria is well-suited for wines fermented and aged on oak where it minimizes astringency and bitterness and masks herbaceous and green flavors resulting in well balanced red wines.
Oenococcus oeni for fast fermentation with enhanced structure and spice (Red)
SOLO SELECT is known to enhance dark fruit and spicy notes, structure and complexity. The production of diacetyl and volatile acidity are low due to the late degradation of citric acid.
All-purpose Oenococcus oeni for enhanced complexity and mouthfeel (Red, White, Rosé)
LALVIN VP41™ is appreciated for its ability to enhance aromatic complexity, richness and mouthfeel in red, white and rosé wines. Red wines have increased currant and berry flavors and aromas, with enhanced coffee and chocolate notes, and sweet tannins. White wines have elevated tropical fruit flavors, apple and pear notes and very low diacetyl levels.