Malolactic fermentation

I've had spontaneous ML occur occasionally - usually with no problem. Normally I inoculate for ML in well clarified juice, usually with culture at the beginning of the yeast fermentation but also with an ML+ barrel. I feel a lot safer putting stuff into the wine that I know should be there, and leaving behind other stuff that maybe shouldn't be there. BTW, I don't add any sulfite to healthy grapes at crush. The wine sees no added SO2 until ML is complete.

Tom S

Once a barrel has gone through MLF, the bacteria remain in the barrel. All of my red wines and Chardonnay are stored in barrels. I rack barrel to barrel, so all of my barrels are infected with ML bacteria. I add a new barrel or two each year, but the new barrels become infected the next time I rack. All of my wines stored in barrels go through MLF, but I haven't inoculated with bacteria for the past several years. Most of my red wines are high pH wines and preventing MLF in them is practically impossible. lum

Many commercial winemakers ferment using indigenous yeast in an attempt to achieve a desired level of complexity or terroir. However, under the conditions required for the use of indigenous yeast (often no SO2 at crush), indigenous ML bacteria may also become active. After tasting several "indegenous yeast fermented" wines (especially after a few years of bottle age), I have to say that I do not like the higher level of "funk" they sometimes have. I have a feeling that much of the unpleasant funk comes from wild ML activity and not wild yeast fermentation. I personally have adopted the use of Lysozyme at 100ppm - 150ppm in my reds at crush to prevent wild ML and innoculate with a clean strain toward the end of primary fermentation. If you want to ferment using indigenous yeast, I would suggest the use of Lysozyme, no SO2 at crush, and cultured ML strains.

CHEERS!

Aaron

All three (Lactobacillus, Pediococcus and Leuconostoc) can produce acetic acid. It is really dependent on the individual strain and environment as to whether it is a more likely to or not. More reliable MLB have a preference for metabolising malic acid over sugars, citric acid, etc - those are what we want.

So as to spontaneous/indigenous MLB, it really depends on what you have "growing" locally and the wine environment that they would grow in. Sometimes you are lucky to have a reliable MLB around and it manages to grow in a suitable wine environment, other times not.

A cultured strain will give you security, an indigenous one could give you more complexity (as many advocates of indigenous MLB/yeast use argue) or it could give you a funky/VA disaster (same as the indigenous yeast issue which Aaron mentioned). Until you try with your given fruit and wine it's not really possible to say which way it will go, so it just depends on how the individual winemaker feels about taking the risk.

That's my take, Ben

So, if I've been happy with the results of all the natural MLF that has occurred so far (which I am), can I assume that my indigenous bacteria are beneficial, or is this likely to change without notice? I don't grow my own fruit, but rather purchase it from a variety of places. I do use all my pressings and lees for compost, but I suppose it takes centuries, not years, for that to have any effect.

I think it's safe to assume so, unless some drastic change to the environment occurs (i.e. the environment of the winemaking, the grape growing, and the wine itself).

If you have been happy so far, the risk talked about before is significantly minimised.

Ben