Malolactic Fermentaton?

Malolactic Fermentaton?

Post by GETaylo » Sun, 27 Sep 1998 04:00:00

What is it? What's the benefit?
What wines benefit from it?
How is it started and controlled?
How long?
Do I need to know(understand) to make champagne?
Anybody know any good references to help?



Malolactic Fermentaton?

Post by NomDeNett » Sun, 27 Sep 1998 04:00:00


An excellent description of Malolactic Fermentation (MLF) can be found in
section 20 of the FAQ for this newsgroup at:

Basically; MLF is not a fermentation at all; but is instead a process
whereby a bacteria culture is introduced into the wine which converts harsh
malic acid into milder lactic acid.  MLF is probably called a "fermentation"
because CO2 is one of its byproducts.  Chemically; here is what happens when
MLF takes place like:

MALIC ACID                                                         LACTIC
------------------                                                         -
H-C-H                   PLUS CO2
     |                       -------Leuconostic
H-C-COOH                     Bacteria--------->                H-C-COOH

To facilitate MLF a culture of Leuconostic (sic) bacteria is added to the
wine.  The bacteria synthesizes the malic acid (harsh "apple" acid) into
milder, creamier lactic acid and CO2.

The benefit of MLF is a less harsh, milder tasting wine.

In terms of wines to target for MLF, as Don has pointed out in the faq,
Pinot Noir tends to benefit.  Additionally; most wines made from grapes
which are grown in very cool climates (especially reds) will benefit from a

In terms of whites, there are split camps on the subject.  Chardonnay is an
excellent example; many robust "California" style Chards are send through a
MLF, while the great white Burgundies are not.

I would recommend experimenting (send a portion of your wine through the MLF
& see whether you like it over the non-MLF batch).

A culture of the bacteria can be purchased from your local wineshoppe (I
think that it costs about $8.00 US).  I know that Lalvin makes such a
culture.  The culture is usually introduced into the fermentation cycle near
the end of the primary fermentation (when both SO2 and *** are at
tolerably low levels).

In terms of the wine's acidity; MLF should reduce your TA by 0.1%-0.3%.
However; the perceived reduction in acidity is substantial.

With respect to Champagne; I don't know if MLF is recommended, but I would
doubt it as high acidity is regarded as a beneficial characteristic of a dry
sparkling wine.

Hope this helps.
"Wine is sunlight, held together by water..."
 -Louis Pasteur


Malolactic Fermentaton?

Post by NomDeNett » Sun, 27 Sep 1998 04:00:00

Sorry Guys:

The MLF formula didn't transfer over to the post very well.

Bascially; one of the dual COOH Karpotov groups of the malic acid is
synthesized into H + CO2.


"Wine is sunlight, held together by water..."
 -Louis Pasteur


Malolactic Fermentaton?

Post by Mr. Fred A. Droe » Mon, 28 Sep 1998 04:00:00

Additional thoughts:  Malolactic bacteria are inhibited by sulfur
dioxide levels over 30ppm.  It is also difficult to start after the
wine is cleared.  Most recommend inoculating the ML culture toward the
end of sugar fermentation to about 2 weeks after completion; certainly
before first racking.
Not recommended for wines with residual sugar that are going to be
stabilized with potassium sorbate.  ML bacteria metabolize the sorbate
with a resultant "geranium" nose.
Once started, it's best to let it finish, else it may start up again in
the bottle resulting in a fizzy wine.

Malolactic Fermentaton?

Post by GETaylo » Mon, 28 Sep 1998 04:00:00

Thanks for the info... it IS very beneficial!