Spontaneous MLF

[Flying Penguin]

Hi all. I usually avoid MLF, since I like a bit of acidity in wine and generally local grapes in Turkey have relatively low acidity due to hot climate. But this year having realized that Merlot grapes that I am fermenting has a too sharp acidic mouthfeel, I decided making MLF and ordered malolactic culture at the last minute. It's been three days after pressing at 0.990 density, spontaneous MLF has started vigorously and I just received MLF culture today from cargo. Does it make a sense from now that I pitch the culture, or should I wait until MLF is completed while checking for off tastes meanwhile?.

 

[MiBor]

How can you tell if you have a spontaneous MLF fermentation right after pressing, or you had uncrushed berries that broke when you pressed and now the sugar from those grapes is fermenting?

In my opinion, if you see vigorous signs of fermentation, that is not MLF. Also, Merlot is notorious for how hard it is to start and complete malolactic fermentation, so spontaneous MLF right after pressing would not be my first guess.

I would let that last bit of sugar ferment dry, taste the wine after the gross lees settled and decide at that time if MLF is needed or not. You can induce MLF at any time after pressing, before adding SO2 to the wine.

We use a method called paper chromatography here in US, to establish if malic acid is still present in wine or if it has been converted to lactic acid, but that may not be available to you. That or laboratory tests are the only methods I know to establish if malic acid was converted or not.

Here is a link to one of these kits:
https://morewinemaking.com/products/chromatography-test-kit-wine-making.html

 

[Rice_Guy]

welcome to WMT
Agreed, you can not say that MLF has started unless you test for it. It is normal for fermentation to occur as successive waves of organisms. Yeast will consume sugar, Oneococcus can consume malic acid, Acetobacter can consume alcohol if oxygen is present. ,,,
There are other families of organisms which can also grow which fall into the group called lactic acid bacteria, especially if the pH is above 3.5. Do you know what the pH is? (pH 3 to 4 test paper is inexpensive)

Flavor wise, the TA (titratable acidity) related to acidic taste. This reflects the number of acid molecules that are in the mouth. Tannin will also magnify the sensation of acid, if you have high tannin you can feel high acid.
Again what is the pH? Wines above 4.0 will likely get a wild infection. Below 3.5 they are quite stable.

 

[Flying Penguin]

Thanks for the answers and for the welcome . I am afraid chromatography test kits suitable for home winemakers are unavailable in my country. So my only option for MLF is to pitch the culture, check for bubbles, wait 4-6 weeks and hope for the best.

Actually I pressed the wine 3 days ago, let the must rest and settle for one day, and then racked to carboys getting rid of gross lees. Before pressing, density was 0.990. I was unaware that uncrushed berries might add sugar to the must, so did not recheck after pressing / before racking. Today i checked again finding out that density is 0.990. So it is completely dry at the moment. There is no off taste or smell indicating a spoilage. The vineyard owner had informed me before buying the grapes that the initial pH of the unfermented must was 3.4 (which was measured the same day by a winemaking company's expert, responsible for checking grape's condition before purchase). I will get a pH meter as soon as possible, but due to the acidic taste, I highly doubt that it is over 4. One thing to add is that fermentation has been extremely slow, it took 17 days to get to 0 brix from 24.5 brix. Temperature was 74 - 77 F. I am also sending a quick video, although I understand that there is no certain way to know it is MLF without chromotography.

So I am going to wait a few more days, see if it is still bubbling to be sure that it is not degassing, checking ph meanwhile, taste and decide whether to let it go or stop it by adding Kmeta.

Thanks for the help!

 

[mainshipfred]

In my opinion the wine is off gassing. The bubbles are too aggressive to be going through malo.