Stopping an active mlf

[painterpat]

Hello everyone. Currently doing a malolactic fermentation for the first time. A Week in and everything going well. I plan to stop based on taste profile and not using a chromatography test (not in the budget for now).
Question is, can an active mlf be stopped with sulphites or pasteurization.
Pasteurization not being the preferred option, but there is a nice 5g lab grade heating mantle at auction today.
Wine is a blueberry, straw berry, black berry blend, lightly oaked. Tasted terribly astringent and harsh. A couple days into mlf it tasted better than the "award winning" wines my relative is always getting me to try. So I'd hate to over do it l.
I know I have a couple more weeks before it's close to being done but I've been looking for this answer for the past week and can't seem to find concrete information adressing my problem. Any information is appreciated!

I also read that mlf can begin eating other compounds after all the malic acid is depleted and produce off flavors. While other sources say it stop on its own. If anyone has experience with it I would appreciate the input on this as well.

 

[BarrelMonkey]

I would not recommend trying to stop MLF'. Once it's done you should be able to treat with KMBS/K-meta to prevent any restart. If you don't have the capacity to test for ML conversion I would give it at least 4-6 weeks before adding sulfites, assuming you're at a suitable temperature and pH for your ML bugs. Tiny bubbles can be a telltale sign of ongoing MLF, but it's not definitive.

I'm curious as to how much malic acid is in the fruits that you mention. I imagine there is a lot of citric acid which can lead to elevated levels of diacetyl (the 'buttery' component of malolactic conversion). As you say, this largely occurs late in the process; though it's not necessarily an 'off' flavor it may or may not be a desirable component of the flavor profile you're trying to achieve...

More on citric acid in winemaking here.

 

[Hazelemere]

Hello everyone. Currently doing a malolactic fermentation for the first time. A Week in and everything going well. I plan to stop based on taste profile and not using a chromatography test (not in the budget for now).
Question is, can an active mlf be stopped with sulphites or pasteurization.
Pasteurization not being the preferred option, but there is a nice 5g lab grade heating mantle at auction today.
Wine is a blueberry, straw berry, black berry blend, lightly oaked. Tasted terribly astringent and harsh. A couple days into mlf it tasted better than the "award winning" wines my relative is always getting me to try. So I'd hate to over do it l.
I know I have a couple more weeks before it's close to being done but I've been looking for this answer for the past week and can't seem to find concrete information adressing my problem. Any information is appreciated!

I also read that mlf can begin eating other compounds after all the malic acid is depleted and produce off flavors. While other sources say it stop on its own. If anyone has experience with it I would appreciate the input on this as well.

to stop mlf chill it and sulphite it

 

[cmason1957]

One way to stop malolactic fermentation is to add Lysozyme (and I may have misspelled that slightly) and probably sulphate at the same time.

 

[mainshipfred]

I find it hard to believe the MLB had any affect on the wine in a couple days. There has to be other factors making the wine less harsh in that short time. It could be very possible it was what you were eating when you tasted it. But to answer your question getting the sulfites up to 70 or so ppm should stop it.

 

[painterpat]

I find it hard to believe the MLB had any affect on the wine in a couple days. There has to be other factors making the wine less harsh in that short time. It could be very possible it was what you were eating when you tasted it. But to answer your question getting the sulfites up to 70 or so ppm should stop it.

I was surprised too. After looking over the strain info they're claiming mlf should be complete in 14 days! But I made sure to do a double test. And it was a definite improvement. Imagine bone dry, straight astringent over powering all other flavors. I suppose any improvement would seem like a vast one. I may be able to get a chomotography kit by the 14 day mark to be absolutely sure and test the manufacturers claim.

 

[painterpat]

I would not recommend trying to stop MLF'. Once it's done you should be able to treat with KMBS/K-meta to prevent any restart. If you don't have the capacity to test for ML conversion I would give it at least 4-6 weeks before adding sulfites, assuming you're at a suitable temperature and pH for your ML bugs. Tiny bubbles can be a telltale sign of ongoing MLF, but it's not definitive.

I'm curious as to how much malic acid is in the fruits that you mention. I imagine there is a lot of citric acid which can lead to elevated levels of diacetyl (the 'buttery' component of malolactic conversion). As you say, this largely occurs late in the process; though it's not necessarily an 'off' flavor it may or may not be a desirable component of the flavor profile you're trying to achieve...

More on citric acid in winemaking here.

Actually didn't consider this too much. I looked I to it and while there wasn't much info on malic acid content in strawberries. Without considering them the mix should be around 2-4,000 mg/l based on averages. While wine grapes can range from 0-8000 mg/l. Seems the blueberries are doing the heavy lifting though. I have some mustang grape wine going and there is 0% Info on the acid content and ratios for them lol I'll have to do get a chomotography test before trying them.

 

[mainshipfred]

I was surprised too. After looking over the strain info they're claiming mlf should be complete in 14 days! But I made sure to do a double test. And it was a definite improvement. Imagine bone dry, straight astringent over powering all other flavors. I suppose any improvement would seem like a vast one. I may be able to get a chomotography kit by the 14 day mark to be absolutely sure and test the manufacturers claim.

What bacteria did you use? I don't recall ever seeing a timeframe on any literature. My experience has been it takes months not weeks.

 

[painterpat]

What bacteria did you use? I don't recall ever seeing a timeframe on any literature. My experience has been it takes months not weeks.

My mistake. I used wyeasty 4007. Got it mixed up with another strain on the morewine site.
Oenos 1.0 is advertised as 14 days and apparently they have an oenos 2.0 that can finish in 10.
Wyeasty 4007 is advertised to finish between 1-3 months.

 

[cmason1957]

History from other folks is that the 4007 never really starts. I seem to remember that the maximum allowed SOw for it is incredibly low. But maybe you got lucky.

 

[Ohio Bob]

I’ve used 4007, but always kept a heat belt on the carboy to keep it at 75F-ish. I usually let it go 2-4 weeks, then sulfite at that racking. Never have done a test to see if MLF was completed. Given the issues people have reported it’s possible I have not been getting the most out of 4007.

I’ve tried other MLB and my process is the same, add the bacteria right around, or even earlier, SG of 1.000. Then heat belt the carboy and wait 2-4 weeks before racking and adding Kmeta.

 

[Rice_Guy]

There are wild lactic acid bacteria that can metabolize malic acid. Some species in this group will metabolize glycerol and produce bitter flavors.
Another factor that helps with control is reducing the pH, ,,, effects are synergistic, ie SO2 is more effective at lower pH.

 

[painterpat]

History from other folks is that the 4007 never really starts. I seem to remember that the maximum allowed SOw for it is incredibly low. But maybe you got lucky.

I try to only add it during the start and transfer to secondary while it's still a little vigorous. Just so I'll ha eve room to hit it with a larger does towards the end. So it shoukd be relatively low so2. I also used icv-d21 which is supposed to be a low so2 producer.

 

[painterpat]

I’ve used 4007, but always kept a heat belt on the carboy to keep it at 75F-ish. I usually let it go 2-4 weeks, then sulfite at that racking. Never have done a test to see if MLF was completed. Given the issues people have reported it’s possible I have not been getting the most out of 4007.

I’ve tried other MLB and my process is the same, add the bacteria right around, or even earlier, SG of 1.000. Then heat belt the carboy and wait 2-4 weeks before racking and adding Kmeta.

Like your style. I'll got it a month- month and a half before adding k-meta. House is kept at 69-72 depending ding on the time of day (texas heat swing the tempeture) on the floor so I'm sure it's warmer than ambient temp.

 

[painterpat]

Thanks for all the info everyone!

Update- came out amazing, stopped at 3 weeks. The wyeasty gave the wine a yogurt aroma and brought out some of the fruit flavors. Giving a berry parfait impression with the French oak giving a nice light oakyness at the end. Really looking forward to see this age, if I can forget that it's in storage. Will definitely be making more.