Stubborn Merlot

[terroirdejeroir]

I made five batches of wine from California grapes: Cab Sauv, Cab Franc, Merlot, Malbec, and Petit Verdot. After alcoholic fermentation was complete I started MLF on each batch using Viniflora Oenos with OptiMalo Plus and they all started nicely. Several weeks later both the Cab Franc and the Merlot got stuck, so I tried to restart with Lalvin VP-41. As I was concerned about providing too many nutrients for the nasties to snack on, I didn't add any additional nutrient. Neither batch restarted successfully, so I tried again with VP-41 and OptiMalo Plus. This approach was successful for the Cab Franc, but still no luck with the Merlot.

I think the problem with the Merlot is the ABV as the initial Brix was 25.9 and I didn't dilute the must. Is it too late to add acidulated water? Would it be a good idea to blend it with the Cab Franc (21.1 Brix) as I am planning on blending eventually? The pH of the Merlot is 3.52 and the ambient temperature is 72 degrees.

I would appreciate any suggestions.

 

[JohnT]

It could very well be that you ABV is too high. at 25.5 brix, your potential abv is 15.5. Vinifloro Oenos is tolerant to up to 15% abv.

You are, however, only slightly above the upper limit. I have found that the level of SO2 is more likely the cause of a stalled MLF. You make no mention of SO2. Do you know what level you are currently at?

 

[terroirdejeroir]

It could very well be that you ABV is too high. at 25.5 brix, your potential abv is 15.5. Vinifloro Oenos is tolerant to up to 15% abv.

You are, however, only slightly above the upper limit. I have found that the level of SO2 is more likely the cause of a stalled MLF. You make no mention of SO2. Do you know what level you are currently at?

John,

I can take a reading this evening, but I have not added any SO2 since the crush in late september. Thanks.

 

[ibglowin]

How are you checking for MLF completion?

 

[JohnT]

How are you checking for MLF completion?

good question!

 

[terroirdejeroir]

Chromatography


Sent from my iPhone using Wine Making

 

[terroirdejeroir]

Sent from my iPhone using Wine Making

 

[ibglowin]

Definitely looks about 50% at best.

Perhaps contact Scott Labs and see where you could pick up a 1-Step Starter Kit

 

[terroirdejeroir]

Definitely looks about 50% at best.

Perhaps contact Scott Labs and see where you could pick up a 1-Step Starter Kit

Ordered. Thanks!

In the meantime I am thinking about mixing a small amount of actively fermenting (MLF) wine with the merlot to see if I can get a culture going. Does that make any sense?

 

[ibglowin]

Sure, nothing to lose!

 

[manvsvine]

Merlot has a resistance to enzymatic break down more than most varietals , so mlf can take longer .

Adding more optimalo and stirring the lees into suspension should be your first intervention . If gently stirring it up once a week after that doesn't help it finish in another 5 weeks , you could pull a gallon of your successfully completed other wine and swap it for a gallon of the Merlot . This is often enough to overcome Merlots natural resistance to mlf .