Quick malolactic question

Would malolactic fermentation happen all the time unless it was stopped by human intervention or does it have to be started once in a while?

Jon, Hi....

In many older wineries the lactic bacteria required for malolactic fermentation (secondary fermentation if we will) is naturally present. In some cases, where malo is desired those natural bacteria are enough - in others lactic bacteria are added. In newer wineries, malolactic fermentation is almost always started after the first fermentation by the addition of lactic bacteria. Under no circumstances will malolatic fermentation take place in the absense of these bacteria.

In either case, when malo does not finish on its own the bacteria can be quite easily done away with by the addition of sulfites to the wine.

Best
Rogov

...In either case, when malo does not finish on its own the bacteria can be quite easily done away with by the addition of sulfites to the wine...

Other forms of human intervention to prevent M-L are sterile filtration and pasteurization. On the non-human intervention side, M-L will not take place if there is too much acid - low pH and high TA, which is one of the reasons M-L seldom takes place in Riesling. Nor does it take place (to my knowledge) in sparkling wines, where the TA is temporarily raised due to the presence of CO2 dissolved in the wine.

I’ll agree with Daniel, besides lactic acid bacteria (LAB) naturally occurring in “older” wineries they could also be present on the grapes themselves. If the conditions (SO2 concentration, temperature, pH, nutrients present, concentration of malic acid) are right they might just do their thing at some time after alcoholic fermentation.

Salute

Is malo more likely to happen naturally with reds?

I have a vague memory of someone saying that a long time ago, and that it was related to reds fermenting at higher temps - so the malo normally kicked off immediately after the main fermentation. While whites had to have their temperature deliberately raised to initiate the malo.

Is malo more likely to happen naturally with reds?

I have a vague memory of someone saying that a long time ago, and that it was related to reds fermenting at higher temps - so the malo normally kicked off immediately after the main fermentation. While whites had to have their temperature deliberately raised to initiate the malo.

Regarding malo in general, what Daniel Rogov said--an excellent summary of the process.

The bacteria involved in malolactic fermentation most definitely require higher temperatures than your typical French cellar in Burgundy has during the winter months. Typically in Burgundy malolactic fermentation, for reds or whites, starts up in March or April after the vintage. Some Burgundy estates have heaters in the cellars so that they can better control the process. I doubt if this is a problem in warmer wine-growing regions such as California. In those warmer climates, it probably does kick off immediately after the main fermentation.

-Paul W.

read between the lines here to note that sulphur levels must fall dramatically for the ML bacteria to start at all. this leaves the wine defenseless against all kinds of bacterial and other attackers. AND, if you have the wrong type of ML bacteria, the wine can have some very bad flavor compounds develope. Its not something you want to do unless you think you have to.

I don't know all the particulars, but while visiting Chateau Lagrange (St. Julien, Bordeaux) last year they told us that they had developed a technique whereby they can have the alcoholic fermentation and the malolactic fermentation take place simultaneously. They viewed this as an economic issue that would save a racking, as I remember. Obviously not a time savings. Interesting concept. We will see if it will (or can, for intellectual property reasons) be adopted by others.

Thank you all; your information filled in some gaps in my understanding. I'm presenting a 101 level wine tasting seminar and was trying to anticipate some questions.

Just as “desirable” wine yeast strains are selected from wineries or vineyards, “desirable” LAB species are selected.

Salute

I don't know all the particulars, but while visiting Chateau Lagrange (St. Julien, Bordeaux) last year they told us that they had developed a technique whereby they can have the alcoholic fermentation and the malolactic fermentation take place simultaneously. They viewed this as an economic issue that would save a racking, as I remember. Obviously not a time savings. Interesting concept. We will see if it will (or can, for intellectual property reasons) be adopted by others.

Richard, I doubt IP issues would be involved since simultaneous fermentations aren't a new thing. Most wineries prefer to wait until very close to the end of primary fermentation or after it altogether because there are risks involved in ML fermentation going on in the presence of sugars. I'll leave the biochemical details to others more knowledgeable but from what I've read, ML bacteria can metabolize sugars into acetic acid. It's hard to know if Lagrange's "simultaneous" means both fermentations actually start at the same time or if they mean ML when primary fermenation is not quite complete, in which case their practice would not be unusual at all. Most winemakers prefer to wait until just after primary fermentation is actually complete because conditions then are most favorable: no sugar and therefore minimal risk of VA from ML fermentation and a high CO2 environment, which ML bacteria also like.

Thank you all; your information filled in some gaps in my understanding. I'm presenting a 101 level wine tasting seminar and was trying to anticipate some questions.

WRT M-L fermentation, malo-lactic fermentation generally takes place spontaneously, in conjunction with alcohol fermentation, during carbonic maceration, which is the whole cluster fermentation technique used to make Beaujolais Nouveau.

After or just before the end of alcoholic fermentation, the dying yeast cells provide nutrients for a growing colony of LAB. Personally I do not believe it is a good idea to have the “desired” wine yeast strain and “desired” LAB competing for nutrients. Here’s a nice article from our friend Ben Rotter:
http://www.brsquared.org/wine/Articles/MLF/MLF.htm

Salute

Is malo more likely to happen naturally with reds?

I have a vague memory of someone saying that a long time ago, and that it was related to reds fermenting at higher temps - so the malo normally kicked off immediately after the main fermentation. While whites had to have their temperature deliberately raised to initiate the malo.

Regarding malo in general, what Daniel Rogov said--an excellent summary of the process.

The bacteria involved in malolactic fermentation most definitely require higher temperatures than your typical French cellar in Burgundy has during the winter months. Typically in Burgundy malolactic fermentation, for reds or whites, starts up in March or April after the vintage. Some Burgundy estates have heaters in the cellars so that they can better control the process. I doubt if this is a problem in warmer wine-growing regions such as California. In those warmer climates, it probably does kick off immediately after the main fermentation.

-Paul W.

I know several pinot noir wineries here in Oregon just have a warm room for malolactic fermentation.