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.

 

[Flying Penguin]

Just for the update, it has been 2 weeks since pressing and it still keeps on bubbling, though not vigourously as day one. I am seeing tiny bubbles like small dots floating steadily to the surface, as in MLF. Wine has a funky taste and smell which goes away after 30 secs of aerating. Meanwhile pH is 2.99 (I double calibrated the phmeter to check). It tastes very acidic, with no tannins and nearly no aroma. I was planning to blend it with Cabs that are on ferment now, but I see that this will only ruin the Cabs as well.

 

[Rice_Guy]

* a new wine should taste carbonic, bitter seltzer notes. You could degas as 50ml in a microwave for 30 seconds > mix > cool > taste. I would also check pH on this sample.
* with the low pH a second test would be 100ml in a small 100ml bottle in a fridge for one or two weeks. This will pull out potassium bitartrate.
* do you have the ability to test for TA? (pH meter, 0.2 or 0.1 normal sodium hydroxide, syringe or burette)

Acidic flavor is related to titratable acidity (total acidity) and is magnified by astringent flavor tannins. The pH is not the key, example coke soda with a pH of 2 isn’t excessively acidic. As a northern grower we deal with high acid all the time.

 

[MiBor]

Just for the update, it has been 2 weeks since pressing and it still keeps on bubbling, though not vigourously as day one. I am seeing tiny bubbles like small dots floating steadily to the surface, as in MLF. Wine has a funky taste and smell which goes away after 30 secs of aerating. Meanwhile pH is 2.99 (I double calibrated the phmeter to check). It tastes very acidic, with no tannins and nearly no aroma. I was planning to blend it with Cabs that are on ferment now, but I see that this will only ruin the Cabs as well.

If it's not a byproduct of a native yeast, I believe the funky smell may be hydrogen sulfide (would explain lack of aroma in your wine) and it would be wise to do a splash racking while the wine still has CO2 in it. You could also use a copper infused product like Reduless or something similar to treat the wine for H2S. Have you used a comercial wine yeast or just the local yeast that lives on the grapes? Native yeast would explain the slow fermentation as well...

As far as pH and TA, you have to test a degassed sample to get accurate results. Carbonation throws off the measurements quite a bit. Also TA is more representative for taste and pH for how long you can store the wine. If you plan on using calcium carbonate to reduce acidity, measuring TA and doing it in small increments with a few weeks between doses is the safe way to go about it.

 

[Flying Penguin]

Thanks for the replies, which have been very insightful for me!

I started using commercial yeast on most of the batch and native yeast on a small part (20 % of the total or so) , just to see and compare the result on two different techniqes. Commercial yeast (fresh package) was slow, meanwhile wild yeast was even slower (in snail speed actually). Assuming that native yeast batch is so sluggish that it may halt at the end, I mixed them during half of the fermentation process. I did not use Kmeta in order to enable MLF while racking.

The off taste and smell is more like sea moss, as it is in a dirty harbor, rather than a rotten egg or sulphur smell. It was not apparent until a few days ago, there was no off taste while racking. In any case, it is obviously no good and there is no need to take the risk of waiting for it to turn something that can not be solved by aeration, so splash racking and adding Kmeta will be my next step. It is still bubbling 15 days after racking by the way.

Great suggestions to measure pH and acidity by the way. I used "the degassing" method to see that pH increased to 3.05, with nearly the same harsh mouthfeel. I will check TA and pH after cold crashing on a small sample as soon as possible!

 

[Flying Penguin]

Cold crashing test significantly improved acidity, I could not believe that much would change. As the harsh taste of acidity improved, subtle aromas have become more apparent. It is still not a big tasteful bomb, but suitable for day to day consumption, and possibly better than what we get here in Turkey about 5-10 USD range. I guess heavy oaking may further improve this batch. Again, thanks for those great suggestions which helped me to assess the situation correctly.