MLF Experiment

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bluecrab

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This is a two-fer experiment. I tried simultaneous inoculation of MLB with the yeast. I also tried inoculating one fermenter with just oak cubes that were present during last year's MLF.

I've tried sequential inoculation and co-inoculation of MLB, in the past. This is the first year that I tried simultaneous inoculation. I added MLB VP41 right before pitching my yeast. Sounds crazy, right? These two references made me want to give it a try.

Lallemand’s “CO-INOCULATION OF SELECTED WINE BACTERIA” says,

“It is important that co-inoculation is done *within* 24 hours after yeast *inoculation*, otherwise alcohol and the competition from the actively fermenting yeast impacts on the inoculated MLF starter."
[https://www.lallemandwine.com/wp-content/uploads/2017/08/WE4-US2.pdf]

“Effects of Different Techniques of Malolactic Fermentation Induction on Diacetyl Metabolism and Biosynthesis of Selected Aromatic Esters in Cool-Climate Grape Wines” says,

“Our research focused on selected aroma compounds (diacetyl and its metabolic products, as well as selected ethyl fatty acid esters) synthesized during malolactic fermentation in white and red grape wines produced by three different methods of inoculation: (1) Coinoculation (COI), where the yeast and bacteria were *inoculated at the same time*; (2) sequential inoculation (SEQI), where malolactic fermentation was induced at the end of alcoholic fermentation; and (3) spontaneous malolactic fermentation (SPONT), where MLB inoculation was not performed.”

“It was found that the fermentation-derived metabolites studied were affected by the malolactic bacteria inoculation regime. Quantitatively, ethyl lactate, diethyl succinate, and ethyl acetate dominated as esters with the largest increase in content. The total concentration of ethyl esters was highest for the coinoculation technique, while the highest concentration of diacetyl was noted for the spontaneous technique. Controlled malolactic fermentation, especially using the coinoculation technique, can be proposed as a safe and efficient enological practice for producing quality cool-climate grape wines enriched with fruity, fresh, and floral aromas.”
[Effects of Different Techniques of Malolactic Fermentation Induction on Diacetyl Metabolism and Biosynthesis of Selected Aromatic Esters in Cool-Climate Grape Wines]

I originally planned to sprinkle the MLB on the must. Unfortunately, I ordered my MLB right before a warm spell in late spring. The MLB spent a week in a hot truck before arriving at my door. The ice pack probably only lasted a day. Was it still viable? I didn’t know. Time for another experiment. I rehydrated the MLB with what ActiML I had on hand (not enough) and pitched it into all of my fermenters, but one. When I bottled my 2019 wine, I saved the oak cubes, knowing I was going to do this experiment. I added 60g of frozen, wine-and-MLB?-saturated, oak cubes to each fermenter. I wanted to know if the fermenter with only oak cubes would go through MLF. If so, I can stop buying MLB going forward.

I pitched the MLB with the yeast on October 4. On October 17, all containers, except the experiment, were done. Apparently, the MLB survived the week in a hot truck during shipping. I have never had MLF results this good, this early. The experimental wine that only received last year's oak cubes, no MLB, was half-done. That's not bad and is typical of my results in previous years. On November 7, the experimental wine was either done or nearly done with MLF. So, I'm convinced that reusing last year's oak cubes to inoculate MLB is a viable, although slower, alternative to purchasing new MLB each year.
 
I also tried inoculating one fermenter with just oak cubes that were present during last year's MLF

reusing last year's oak cubes to inoculate MLB is a viable, although slower, alternative to purchasing new MLB each year.
This is exactly what I asked mainshipfred recently, so thank you for doing this experiment for me! I have put oak cubes onto wine that appears to have started a spontaneous MLF, hoped to just keep them in bottled wine for next year. I may buy a package of bacteria so that I am sure which type I have, but wasn't sure if this would work overall.
 
Nice!

I believe a lot of commercial wineries don't actually inoculate, rather they put their wines into barrels that have already had MLB in them.
 
This is exactly what I asked mainshipfred recently, so thank you for doing this experiment for me! I have put oak cubes onto wine that appears to have started a spontaneous MLF, hoped to just keep them in bottled wine for next year. I may buy a package of bacteria so that I am sure which type I have, but wasn't sure if this would work overall.
I just gave the oak a quick rinse in cold water, put it in a Ziplock bag, and threw it in the freezer.
 
sounds good. maybe i'll give it a go next year cause all my carboys have gone through MLF with oak cubes in them. i'll pluck them out after cold stabilization is complete. thanks for the tip
 
Thanks for sharing the experimental results. I do sequential innoculation and don't count on the existing flora population in the barrels to eventually get the MLF done. I prefer to get it done, get the sulfites added and then age in the barrels.

One experimental data point I'll add here is that when I ran my chromatography test this fall I also tested a batch of chilean carmenere that I've had in tank since spring. It was never given MLB and has been regularly dosed with SO2 but it clearly had a lactic spot on the chromatography paper. There was also a noticeable malic spot so it didn't complete MLF. Anyway, it shows that even under controlled and adverse circumstances that MLF can happen spontaneously.
 

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