malolactic fermentation

Feb 21, 2008 18 Replies

This is a subject that has come up time from time in this group. I think i have read up on this enough to know what it is, and how to work with it.



My bigger question is this. How many of you out there that re trying to make a quality dry red wine actually induce a Malolactic fermentation cycle.



Here is why I ask. I plan on getting 75 gallons of fresh crushed California Cabernet Sauvignon grapes this fall and want to take my wine making to the next level on both quality and quantity.



I am reading furiously and meeting folks who make a lot more wine than I do. Twice now, I have personally met winemakers that have been making wine for 50+ years and ask them a technical question about freee SO2 or PH levels, or Acid blends, and both times i get the same general response: An exhasperated "Wayne, I just smash the grapes. You are waaay over thinking it."



Not those words exactly, but close.



So my question is this. How many folks really do go out and buy the malolactic cultures like leuconostoc oenos and induce MLF? Is this common?


I would say 'yes - it is very common'. One of the main reasons for inducing MLF is to ensure that the subsequently bottled red wines don't spontaneously go into MLF while in the bottle. Another is to change the acid profile, thereby the taste profile (malic acid being a crisper, more tart taste, better suited to crisp, lively white wines).

Possibly you are overthinking things. Then again, possibly those two winemakers are underthinking things.

Do you use chromotography to monitor your MLF?

Paper chromatography, yes. But it is a once a year sort of deal. I test my reds to ensure that mlf is complete before I consider bottling. In my cellar, mlf usually gets going well soon after primary, but then stalls during the winter (temps in the cellar drop to anywhere between

56 and 59). Kicks in again in the spring. But I always test later in the year to be sure - before bottling.

I hate to keep bending your ear, but I will until you tell me to stop. ;)

When, relative to primary fermentation, do you innoculate for MLF? at start?

-or-

50% through? 75% through? 90% through?

This is the question that will likely generate some debate.

I used to innoculate soon after primary was underway, on the presumption that the ml bacteria would get a better start while the alcohol was lower. Then, some fellow winemakers who profess to knowing far more than I ever could suggested that I was risking some undesirable volatile acidity by doing so (I am still uncertain of the biologic basis for this). So I now innoculate late in primary - soon before press. Not sure it really makes a difference, but done this two years in a row now with no problems, so planning on continuing thus until better information convinces me otherwise.

How about you? When do you innoculate with ml bacteria?

When do I Inooculate? Let me quote a wise man: "So I now innoculate late in primary - soon before press."

:)

I've never done it. But read enough to know that I think i should be. BTW, everything I know about MLF I am reading in Philip Jackisch's "Modern Winemaking" book. In it, he states: "The ML culture can be added to red wines at the time of pressing, ordinarily at about 5 deg Brix. and should be 1-5 of the volume of the juice." That is from Chapter 5 "Microorganisms and Fermentation" Page 79.

So, sounds like the old timers were dead on.

Only thing I don;t understand there - "shold be 1-5 of the volume of the juice" ?? what does that mean?

I buy the small dried bacteria packets. I pitch them directly into the fermenting must. Some folks start it in water, much as we do yeast (for my reds, i figure it has a year or two to do it's thing, so I'm not too worried about making it start right away - but it always does!).

Sorry - potential Typo:

Should have read "1-5% of the total volume"

Very sorry.

Lum is much to modest:

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Look for: ferment sugar

Take Care, Steve Oregon

Nice read, Thanks Steve.

In reading from the

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web site about ML cultures I read this:

"Note: Malolactic bacteria added during the ferment will compete with the yeast for nutrients and are atagonistic to yeast, sometimes causing problems resulting in stuck or stalled fermentations. The best time to add an ML culture is after racking off the gross lees.."

With so many variables and so many opinions involved in winemaking, I am beginning to think it takes a pointy hat with moons and stars on it to make good wine.;)

Ok, just to muddy the waters a bit, I rarely induce MLF because most of my grapes are low acid to begin with. Proper sulfite levels can be used to prevent spontaneous MLF. It really depends on your grapes, if they are on the underripe side they will likely be high in TA, lower in pH and great candidates for MLF. Mine are usually the opposite. If you do this, I prefer later in the ferment too; the TA/ pH balance is closer to stable and you know where they ended up; the sulfite level has dropped to the point MLF can take off too.

As to cultures, once ML bacteria are in your winery space it just happens on it's own. I know that seems a little hard to believe, but I keep things relatively clean and get spontaneous MLF often if my sulfite levels dip. If the wine is a little high on TA I let it have at it. I'm either bringing it in on the must or it's in my winery. I never saw it before I bought a culture for some Chancellor so suspect the latter.

Joe

Joe

Joe ,

I don't add MLF culture and I can smell the MLF starting about half way thru the primary anyway. I would think adding MLF culture just before pressing would be wasting alot if a non bayanus strain of yeast that promotes MLF was used in the primary. I would use prisse de mousse on a red if I wanted to wait until after the primary to start MLF and also add MLF nutrients with the culture. JMO.

Bob

You either have a good nose, or MLF has a distinct odor. \ :) Can you describe the odor?

You either have a good nose, or MLF has a distinct odor. \ :) Can you describe the odor?

I think wines going through MLF often have a slight "sour cabbage" smell.

Lum,

I smell diacetyl. It's quite strong by the time I start pressing. I assumed that meant MLF was going. Am I correct to assume that or does that smell come from some other process during primary??

TIA

Bob

The red wines I ferment are eastern reds. They have much more Malic acid so I think the smell is stronger. I think if I remember correctly, your from SD and those grapes probably have less malic acid. The buttery smell has been pretty noticable about 1/2 - 3/4 way thru primary. I also see that "sparkle" type of fermenting when pressing which I associate with MLF. It's a different type of bubble action. It's tough to discribe except that I know it's MLF still going.

Bob

I think you are right Bob. I am in San Diego and local red grapes often contain less than 2 grams per litter of malic acid. So, mlf doesn't last very long or produce very much diacetyl. I know what you mean about mlf bubbles. They are different, but difficult to describe. Lum

Bob

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