How do you measure malolactic fermentation

[wood1954]

Say what? It is common to adjust the pH of must or wine with tartaric acid, no doubt, but your statement here is misleading. Even with "hot climate (red) grapes" (which are basically all red grapes/wine in California), still need to go through MLF to assure stability. And honestly, even if not deliberately inoculated, the majority of wines are going to go through MLF eventually anyway, since MLB is present on grape skins. So it's best to control this aspect of wine making. The green apple taste of malic acid is another issue too. It just isn't desirable in red wine.

I'll make a blanket statement that is correct 99% of the time:

All red wine needs to go through MLF.
In white wine making, MLF is a stylistic choice.

Anyway, the pH and ability of a given level of SO2 to protect the wine is a different issue than whether or not a wine should go through MLF. For practical reasons and to keep sulfite levels in check, it is helpful to treat white wines with lysozyme to prevent MLF, if MLF is not desired.




Even in this described circumstance it is still helpful to do MLF. The pH and whether MLF is desirable are completely unrelated issues. The taste of malic acid is not appropriate in red wine. There may be rare exceptions but I can't think of one. Adjust the pH and acid levels as much as you like with tartaric acid.

I agree, malic is too harsh for red wine,

 

[winemaker81]

All red wine needs to go through MLF.
In white wine making, MLF is a stylistic choice.

Nope.

And not all reds undergo MLF spontaneously. The difficulty folks have with intentionally getting MLF to initiate and/or run to completion is good evidence of that. A heavy red is not a good environment for MLF, especially with the addition of K-meta. According to the Scott Labs FAQ I posted above:

An optimum environment for malolactic bacteria includes a temperature between 20-25°C (68-77°F), alcohol below 13% (v/v), total SO2 below 25 ppm, pH above 3.4, little or no oxygen, low levels of short and medium chained fatty acids, low levels of organic acids and low levels of polyphenols.​

My heavy reds are far from an optimum environment for MLF in general, and I have never inoculated.

 

[CDrew]

And not all reds undergo MLF spontaneously.

I don't think I said that they do. I said they usually do. But because of that, there is your reason to control the situation. There are 2 main reasons to do MLF. The first, is stability of the wine. Wine with malic acid may go through MLF in the bottle, and thus result in a fizzy wine at best or a bottle bomb at worst. SO2 may help control that for a time, but SO2 declines over time setting your up for MLF in the future. It's best to avoid that whole scene and have your red wine go through MLF. The second reason, is that malic acid tastes like green apples. Can you think of a time when you want that taste in a red wine? Again, better to control this whole situation and deal with a known issue up front.

From the tone of your post, I suspect you are not testing your finished product for the presence of malic acid? If not, run a few chromatography tests and see what does or doesn't undergo MLF. The results will likely confirm what I'm talking about. If you are using barrels, the barrels themselves are likely the source of your MLB fermentation. I think that's pretty cool and I know that in France MLB are rarely added, yet the wine undergoes MLF anyway, often in the spring after the fall fermentation.

My heavy reds are far from an optimum environment for MLF in general, and I have never inoculated.

Not sure what to make of this except that you are burying your head in the sand. It's always better to know what you are dealing with, and approach it with careful thought and testing. Maybe if you are talking kit wine, this is a reasonable approach, but you really need to consider the possibilities when making red wine from grapes.

White wine is a whole different thing, and the malic acid taste can be a welcome part of the taste profile. But it too will undergo MLF most of the time without a control of some sort like lysozyme.

 

[winemaker81]

But because of that, there is your reason to control the situation. There are 2 main reasons to do MLF. The first, is stability of the wine. Wine with malic acid may go through MLF in the bottle, and thus result in a fizzy wine at best or a bottle bomb at worst.

I've made a lot of wine over the years, have never inoculated for MLF, and the only times I've had a fizzy wine was early on because I didn't let fermentation complete. This is not a problem in my experience. I've also not had a problem with red wine tasting like apples.

From the tone of your post, I suspect you are not testing your finished product for the presence of malic acid?

Never saw the need.

Not sure what to make of this except that you are burying your head in the sand. It's always better to know what you are dealing with, and approach it with careful thought and testing. Maybe if you are talking kit wine, this is a reasonable approach, but you really need to consider the possibilities when making red wine from grapes.

No offense, but it seems like you have a solution in search of a problem.

It is possible MLB is in the barrels. I'm going to ping the original owner and ask if they inoculated.

A few things make be believe it's not, one of which is I put FWK in the barrels in fall 2021, and evidence is that kits are unbalanced by MLF, but both wines taste fine. We compared the topup to the barrel wine, and they were different in tannin and fruitiness, which is expected from barrel aging.

Second, we just taste tested the topup vs barrel for the Tempranillo, and while the tannin and fruitiness were clearly different, acid levels tasted about the same.

 

[HoCo Al]

I've been studying up on MLF recently since I'm still pretty new at winemaking. A commercial vineyard owner whom I know posted a link on another wine forum to an excerpt from a Lallemand book on MLF that was a real eye-opener. (Link below.)

It seems that there has been a lot of activity in the last 15 or 20 years or so on studying the various species and strains of lactic acid bacteria (LAB) and the complex chemistry associated with MLF. As a result, it appears that there are various "organoleptic" effects of MLF, both positive and negative, that occur as a result of MLF. These effects can differ due to the specific type of LAB -- intentionally inoculated or not -- that acts on the wine during MLF. They can also differ -- sometimes in significant ways -- with the same strain or species of LAB at low pH vs. high pH, and can differ depending on the alcohol level.

It seems that commercial winemakers are now experimenting with MLF both in red and white wines to help "sculpt" the flavor profile. In the case of reds, for one example, the specific species or strain of LAB chosen for the MLF inoculation can have the effect of either masking or bringing out more fruit character; and the same can happen for other flavor characteristics. As for white wines, in addition to being used sometimes in white wines other than Chardonnay mainly to reduce acidity in wines from cold regions, different cultivated strains of LAB are now being used to change, sometimes significantly, the "organoleptic profile" of white wines. As a result it is now being suggested to select the specific type of LAB according to both the type and characteristics of the particular wine and the end result the winemaker wants to achieve. In any case it sounds like it is definitely not a good idea to leave it to chance and risk an MLF that is conducted by an indigenous LAB of the wrong type that may have a negative effect on the flavor of the wine.

Anyway, I'm finding this fascinating. I didn't realize there was so much to learn, and so much new research being done, regarding MLF. Here is the link to the Lallemand book excerpt:

MALOLACTIC FERMENTATION- IMPORTANCE OF ...Lallemand Winehttps://www.lallemandwine.com › 2015/10 › La...

Note: I was told on another thread that the correct abbreviation for malolactic bacteria is MLB, not LAB. This Lallemand book excerpt in fact uses both LAB and MLB; however the vast majority of the references to the malolactic bacteria in the book use the LAB abbreviation, so I settled on LAB in this post for that reason.

 

[Rice_Guy]

@HoCo Al excellent insight. I was bottling two apple based wines last week and scratching my head. Starting apple juice is 3.3 or 3.35 and this cyser and mixed fruit were at 3.8 and 3.91. With the mixed fruit the flavor was muddy/ dirty and improved when I pulled the pH down with phosphoric acid. ,,, excellent!

I do not like “LAB” because to me you are opening the field up to organisms which I would use in sour kraut or silage for cows. “LAB” is a term used when taking microbiology at Wisconsin or a course in making dairy products (yoghurt/ cheese) at Wisconsin, if these families were found in wine it would imply an infection.

 

[HoCo Al]

@HoCo Al excellent insight. I was bottling two apple based wines last week and scratching my head. Starting apple juice is 3.3 or 3.35 and this cyser and mixed fruit were at 3.8 and 3.91. With the mixed fruit the flavor was muddy/ dirty and improved when I pulled the pH down with phosphoric acid. ,,, excellent!

Not really my own insight, so I won't take credit for it. Reading the Lallemand book excerpts lit up a light bulb for me on things that I need to pay attention to and consider -- and that I had no idea were important or even relevant -- to maximize my chances of making a good wine.

I do not like “LAB” because to me you are opening the field up to organisms which I would use in sour kraut or silage for cows. “LAB” is a term used when taking microbiology at Wisconsin or a course in making dairy products (yoghurt/ cheese) at Wisconsin, if these families were found in wine it would imply an infection.

I'll speculate that one reason "LAB" is being used, at least in some of these articles and writings, is that there is a relatively new and tantalizing realization that there are many different strains of bacteria -- in some cases different species and even different genera other than the presumptive favorite O. Oeni MLB -- that can be used for MLF with favorable results. So it may be a way on the part of the authors of bringing attention to the broadening of the classes of organisms that can and can and are being used successfully for MLF.

 

[Raptor99]

Here is a fairly technical discussion of the use of LAB for MLF: Lactic Acid Bacteria Contribution to Wine Quality and Safety Much of this article is over my head, but I can pick out a few useful tidbits by skimmig through the article.

Different species of LAB (Lactobacillus) are used to produce yogurt, sauerkraut, kimchee, or MLF in wine. Many eat carbohyrates to produce lactic acid. Some eat malic acid, which are the ones used for MLF.

 

[HoCo Al]

Here is a fairly technical discussion of the use of LAB for MLF: Lactic Acid Bacteria Contribution to Wine Quality and Safety Much of this article is over my head, but I can pick out a few useful tidbits by skimmig through the article.

Different species of LAB (Lactobacillus) are used to produce yogurt, sauerkraut, kimchee, or MLF in wine. Many eat carbohyrates to produce lactic acid. Some eat malic acid, which are the ones used for MLF.

Thanks, Raptor. Having already read most of the Lallemand book excerpts made it easier for me to read and at least partially understand the article you linked to. For me some of the most important information in the Lallemand book related to the contribution that LAB can make, or not make, to volatile acidity (VA), depending both on the particular LAB type chosen for the MLF, but equally important the conditions into which it is introduced when you inoculate.

The Lallemand book discusses in some detail the effects of the variation in timing of when the LAB is introduced; not just co-fermentation vs. sequential, but also, for co-fermentation, exactly when -- i.e., at what stage of the progress of the AF -- you inoculate. The way I read it (though I may have gotten it wrong) is that it is generally not a good idea to inoculate for co-fermentation be simultaneous of immediately after inoculating with the yeast. Rather, the LAB should be introduced later during the alcoholic fermentation; and even there there are pros and cons as to exactly when, esp. wrt production of VA, which we want to avoid. pH is also critical, as well as temperature. The bottom line is that the chemistry of the LAB acting on the wine during MLF can differ depending on the conditions and so the MLF can cause the wine become better or worse in terms of flavors and aromas, depending on those conditions, in part depending on the specific types of yeast and LAB used.

Complex subject, but according to my commercial winemaking friend from the other forum who put me on to the Lallemand document, he has been able to significantly improve his wines, reduce VA, and win more "Golds" for his California wines in part by modifying his approach to MLF. One very specific thing he mentioned was that his winery is now co-fermenting all of their reds "whenever possible" so as to "leave nothing to chance". That, he said, was because through testing they found that in about 33% of the reds MLF had already started during AF even though they had not yet inoculated for MLF. So the implication is that the LAB that had spontaneously begun the MLF during AF may not have been a desirable one.

P.S. I liked what I saw in the Lallemand excerpts that I wound up ordering the whole book from someone on Ebay that was selling it for $17. The only other way to get it is directly from Lallemand, and I'm guessing you might have to be a commercial winery to get it from them, at least for free.

 

[BarrelMonkey]

That, he said, was because through testing they found that in about 33% of the reds MLF had already started during AF even though they had not yet inoculated for MLF.

Interesting... I'm pretty sure that's what happened to my 2023 syrah. Went through AF, pressed out to barrel and keg and then inoculated with MLB. I actually used 2 inoculations because the first didn't seem to work, but the second was just as anemic. But, several weeks later my chromatogram showed robust ML conversion. I didn't have the presence of mind to save a 'before' sample for comparison.

Based on how I was taught I've always waited until wine was bone dry before pitching MLB (due to concerns about VA production) but I might just try coinoculation this year.

 

[Rice_Guy]

the chemistry of the LAB acting on the wine during MLF can differ depending on the conditions and so the MLF can cause the wine become bitter or worse , , , . So the implication is that the LAB that had spontaneously begun the MLF during AF may not have been a desirable one.

reading in this area I pick up
* The family of LAB is fairly large, the current article lists 44 types of LAB found in 254 samples of juice which were collected in that grape region. O. oeni (our commercial type) was just one and with that the authors detected 53 strains. Genetic testing is letting them look at the world in more depth than when i was taking micro.
* a starting juice will have between 1000 and 10,000 colony forming LAB organism per milliliter. At the end of alcoholic fermentation the count is down to 100 per ml. Most families can not survive in the must pH , and with SO2, and with alcohol in the wine,
* bitter flavor notes are attributed to four of the species, glycerol is decarboxylated to produce acrolein which in quantity will cause cancer in rats, ,,, we really want to avoid it
* bactiless could be used to prevent many lactic acid bacteria families as well as VA. Lysozyme will prevent many LAB families but not VA.
* There is a lag phase between when yeast do reproduction and when LAB start actively reproducing. Malic may start decreasing with wild types at two days.
*. As HoCoAl noted it is complicated with many different carbon sources metabolized and a variety of end products.
* In my situation Lallemand tech service suggests I could add bactiless at the beginning and have a stable pH. One implication on white grape is that bitter flavor notes could also be prevented by adding bactiless or lysozyme.

This is an interesting rabbit hole, the technology has evolved a lot in the last ten years. Expect more in the next ten.

 

[HoCo Al]

reading in this area I pick up
...
* bactiless could be used to prevent many lactic acid bacteria families as well as VA. Lysozyme will prevent many LAB families but not VA.
* There is a lag phase between when yeast do reproduction and when LAB start actively reproducing. Malic may start decreasing with wild types at two days.
*. As HoCoAl noted it is complicated with many different carbon sources metabolized and a variety of end products.
* In my situation Lallemand tech service suggests I could add bactiless at the beginning and have a stable pH. One implication on white grape is that bitter flavor notes could also be prevented by adding bactiless or lysozyme.

Interesting that you mention Bactiless. In the same thread on the other winemaking forum I alluded to above, my California winemaking friend said the following:

"We started using Bactiless on everything- white, rose and red. The benefits are worth every penny. We've seen lower VA (acetic) numbers across the board. Granted, it does not reduce VA, it helps prevent it from occurring from bacterial infection."

In another post on the same thread he added:

"We add it [Bactiless] to reds as soon as MLF is done in the barrel and then rack. This is a racking that would likely happen regardless. Whites get it right after AF is done.

The use of bactiless only lessens [the] bacterial load. It is not a substitute for all the protections offered by SO2. .4 is a little low especially when you consider how fast it can be consumed/bound. We shoot for .5+ and try to catch it so it does not go lower than .3 on reds."

So I am now trying to decide whether to buy a 500g bottle of Bactiless now to add to all of my wines that are currently in bulk aging, or just wait until next season and start fresh with the new wines. I believe it has a relatively short shelf life, perhaps a year or less. One way or the other, though, I've decided that I will be using Bactiless going forward.

 

[HoCo Al]

I looked into the Bactiless shelf life. The mfr. -- Lallemand -- says the following:

STORAGE & SHELF LIFE
Store in a dry and cool place.
Shelf life: 4 years in original sealed packaging.

It will have an expiration date on the label. According to Scott Labs it must be kept at a temperature below 25 °C / 77 °F.

So I assume if I buy a new bottle now from a retailer it will probably be good for at least 3 years. However if I use only a portion, it is no longer guaranteed through the expiration date since the package will no longer be sealed.

The plan: I'll buy a 500g bottle now, use as much as I need this year, probably 100 - 200 g, based on their recommended dosage of 20 - 50 g/hL. Transfer the remainder to one or two small amber glass jars that can be tightly sealed with Teflon-lined caps, and store them in the wine cellar at 56 °F or so until next season.