Will adding 71B yeast reduce malic acid post-primary fermentation?

[Stella]

Brand new winemaker and I have about 8 gallons of various fruit wines that have just finished primary fermentation or will be finished soon.

If I don't want malolactic fermentation to occur, or if I want to decrease its effect, could I try putting some of the 71B yeast in there? If so will I need to add some sugar with it? If this were to work would doing it as a small additional fermentation be worth it?

(My abv% is around 10% so I can increase my alcohol a bit if need be. Also I didn't dilute anything so my apple and blackberry wines are 100% fruit based which makes me think there is a LOT of malic acid?)

For future reference would using 71B as my primary fermenting yeast be useful or would the effect on an undiluted apple wine be worth it?

Thanks for any help.

 

[CDrew]

Putting in more yeast now will not do anything. If fermentation is done, it's done.

If you want to prevent spontaneous MLF, you can add Lysozyme and then sulfite, which will kill the malolactic bacteria and keep MLF from happening.

 

[Stella]

Putting in more yeast now will not do anything. If fermentation is done, it's done.

If you want to prevent spontaneous MLF, you can add Lysozyme and then sulfite, which will kill the malolactic bacteria and keep MLF from happening.

Thank you so much! I'm about to place an order for more supplies and I will get some Lysozyme.

 

[winemaker81]

MLF only occurs if the wine has sufficient malic acid -- most fruit wines don't. A chart was posted on the forum a while back, listing the acids prevalent in various common fruits. Apples contain malic acid, but I cannot recall other fruits that do.

AFAIK, a sufficient K-meta level will inhibit MLF, possibly as little as 1/4 tsp K-meta per 5 US gallons. Lysozyme is used when a wine has undergone MLF and the winemaker wants to stabilize with sorbate prior to backsweetening, to avoid off-flavor problems the result from MLB with sorbate.

I don't believe lysozyme is necessary unless the wine has undergone MLF.

 

[Stella]

MLF only occurs if the wine has sufficient malic acid -- most fruit wines don't. A chart was posted on the forum a while back, listing the acids prevalent in various common fruits. Apples contain malic acid, but I cannot recall other fruits that do.

AFAIK, a sufficient K-meta level will inhibit MLF, possibly as little as 1/4 tsp K-meta per 5 US gallons. Lysozyme is used when a wine has undergone MLF and the winemaker wants to stabilize with sorbate prior to backsweetening, to avoid off-flavor problems the result from MLB with sorbate.

I don't believe lysozyme is necessary unless the wine has undergone MLF.

I really appreciate the info. It's just years ago I made some wine and gave some bottles as gifts and was embarrassed that they were still a bit unfinished so I'm really trying to make sure I understand when my wine is finished.

I do have an apple/pear wine and have used apple as a kind of base in two other wines, always undiluted fruit, so I felt like I had to address it. Preferably preventing the process but at least wanting to know if it has happened or if it's not going to happen.

Do you know if I can test for malic acid and if so is there a known threshold where it will likely undergo the process?

Thank you very much.

(I mean it is something to consider right? It can potentially have a significant effect right so that I should determine whether I want it to happen or not?)

 

[winemaker81]

The folks who intentionally inoculate with MLB, use chromatography to check the level of remaining malic acid.

You can search the forum for threads involving MLF. K-meta will inhibit it, the amount varies by MLB strain, but it's not high. Adding 1/4 tsp K-meta per 5 US gallons (~50 ppm) should prevent MLF.

I can't recall hearing of apple wine going through MLF without specifically being inoculated, so I don't believe you have anything to be concerned about.

 

[winemaker81]

Folks that want MLF intentionally, go with no or low k-meta to get MLF going. It seems somewhat difficult, so having it happen unintentionally is not likely

 

[Stella]

Great! Thanks so much. That would explain why with ALL that I've read and watched in the last few weeks it was only mentioned a couple of times, and not once among the recipes I found. So I'm just going to go forward with little to no concern lol. I think the term "buttery" was a source of my worry. It's not a trait I desire at all with the wines I am making. Honestly I can't think of a wine that I would care to try where "buttery" was a descriptor. Thanks again.

 

[Rice_Guy]

To the earlier post; yes 71B is rated as consuming 33% of the malic acid. This can be significant if you are fermenting apple or peach where malic acid is the dominant acid. It can be insignificant if you are fermenting citrus or raspberry which don't have much malic.

Like you I try to ferment 100% fruit juice and not add water. My fix on a finished wine usually is that if the total acids is high I can back sweeten to 1.010 or 1.015 to bring the flavors in balance. Now all that said a young wine risks turning into a bomb so I try to age over nine months before back sweetening. If you back sweetnen a young wine (yeast still floating in it) add potassium sorbate to keep the yeast from growing a second time.