The application of malolactic fermentation process to create good-quality grape wine produced in cool-climate countries: a review

Małgorzata Lasik

doi:10.1007/s00217-013-2083-x

Abstract

The work presents the essence of the secondary fermentation occurring in the course of grape wines production—malolactic fermentation (MLF). The selection of wine yeast and bacteria preparations, scenario of malolactic bacteria inoculation as well as control system of the process conditions are proposed to create the specific character and style of grape wines produced in cool-climate countries, in which the acidity of grape must is often significantly enhanced and the concentration of aroma compounds is considerably low. The role played by appropriately run MLF is presented, along with the advantages and disadvantages of the process, benefits, and technological drawbacks resulting from the introduction of this procedure to the vinification process. Moreover, methods to initiate and run MLF as well as interactions occurring between microorganisms used in wine production, i.e., wine yeasts from the genus Saccharomyces and wine bacteria from the genus Oenococcus, are also presented and discussed.

Highlights

A cool climate and potentially disadvantageous conditions for grape vine growing do not have to exclude the wine production potential of a given region, while in many countries, they have proven to promote, rather than prevent, in European countries with a cool climate, it is possible to produce wine with an original, regional character, exceptional in the mass scale production of imported wines
An ideal solution for processing of such raw material is provided by secondary fermentation, initiated usually toward the end of alcoholic fermentation, i.e., the so-called malolactic fermentation (MLF)
Only in countries with high public awareness of winemaking techniques, almost all red wines, most sparkling wines, and a portion of white wines are subjected to secondary fermentation

Summary

The essence and role of MLF in winemaking process

The primary and most significant process during wine production is ethanol fermentation, i.e., enzymatic decomposition of sugars to ethanol and CO2 under the influence of yeast activity in anaerobic conditions. Bacteriocin-like inhibitory metabolites of Oenococcus due to the narrow range of activity should not influence metabolic activity of wine yeasts They may prove to be an effective tool in the control of lactic acid bacteria responsible for the production of metabolites deteriorating wine quality, mainly polysaccharides, diacetyl, acetoin, acetic acid, or acetaldehyde [12, 13, 18,19,20,21]. The process itself is not controlled, but rather only observed and in the case of any signs of adverse changes, young wine is immediately decanted from above the lees and it is sulfitated in order to completely stop fermentation Such an uncontrolled process is highly risky and may cause disqualification of the produced wine as a result of accumulation of adverse metabolites of lactic acid bacteria. There is a risk that undesirable compounds may be produced, which detract from the quality and acceptability of the produced wines [48, 49]

Principle of MLF initiation and management

Prior to completion of alcoholic fermentation

After alcoholic fermentation

Findings

Interactions between yeasts and bacteria