MLF...

[BernardSmith]

I am planning to make my first batch of grape wine from whole grapes in a few weeks and am thinking about MLF. My batch size is likely to be about 6 gallons so I don't need a pack of bacteria that will make 60 gallons. WLP675 seems to be made for a wine maker like me... but is this a reasonably good strain of bacteria? How is it normally shipped - chilled or simply placed in an envelope and mailed? In addition, Whitelabs suggest that this strain is good with wine yeast nutrient but they recommend that one should pitch the WLP675 just prior to pressing, and so my thinking is that the nutrients will have been used up by the yeast. If so, has anyone with experience with these bacteria added more nutrient with their addition or is there enough nutrient in solution to take care of their needs? Thanks

 

[cmason1957]

I have never used the WLP675, so take this with somewhat of a grain of salt. Hopefully someone who has will comment.

The nutrients you add for successful alcohol fermentation to finish are much different than the nutrients for malolactic fermentation to finish. I always use Acti-ML to rehydrate the Malolactic bacteria and wake it up in a nice gentle way. I also add Opti-Malo Plus to the wine a day or so prior to adding the rehydrated ML Bacteria to the wine.

I believe that the WLP675 is in a liquid form and you can skip the Acti-ML step, but I see on the morewinemaking site these warnings - Free SO2 should be less than 10ppm (to me that means don't add any at crush) and White Labs recommends pitching this strain at around 5 Brix remaining sugar in your primary fermentation. MoreWine! recommends that you follow the manufacturer's suggestion in this regard, but that you still rack off your gross lees withing 48hr of pressing and that you continue to stir the fine lees twice a week until the end of MLF.

 

[BernardSmith]

I read - somewhere - that if I add the normal amount of SO2 at crush then by the time I am ready to press there should be not much more than 10 ppm in solution - assuming say 2 -3 days cold maceration and about a week to 10 days of fermentation... No?

 

[cmason1957]

I read - somewhere - that if I add the normal amount of SO2 at crush then by the time I am ready to press there should be not much more than 10 ppm in solution - assuming say 2 -3 days cold maceration and about a week to 10 days of fermentation... No?

If the grapes are in good condition, I generally don't add any KMeta at crush time. I believe (and I've never seen this published, so maybe I'm wrong), that both the free and total SO2 matter to most of the MLB and can cause issues with it. So, I tend to not use SO2, if I am going to inoculate. I don't know if this is the right thing to do or not and take it for what it is worth. The simple answer to your question is I don't know.

 

[BernardSmith]

OK but what is the temperature of your maceration? And how good a quality are the grapes you get? There is no concern for aceto bacter infections?

 

[cmason1957]

With the types of grapes that I get (almost all hybrid, Vinifera are cost prohibitive for me in Missouri, $2 and up per pound and my CFO says no go), and usually Chambourcin, Norton, and St. Vincent cold maceration isn't a required thing for wonderful extraction of color. I get very dark, almost inky black wine without it. I generally bring them home, crushed and destemmed, let them sit overnight in my cold basement, pitch the yeast the next day. So no, I don't worry about aceto bacteria infections.

As I said, I don't know how much SO2 will be left, but 10 ppm isn't very much at all, probably well below what the nose can detect.

 

[stickman]

It's actually more important to use SO2 for an uninoculated must, as the SO2 will suppress the more sensitive microbes and allow stronger yeasts to prevail. If you are intending to inoculate with cultured yeast, then the need for SO2 is reduced or eliminated. Damaged fruit is the main source for acetobacter and other microbes, so sorting through the fruit is important. Acetobacter is not affected by normal doses of SO2, so it should be understood that acetobacter will be in your wine at some reasonable cell count, and the primary control is minimizing oxygen after fermentation is complete. I use only low doses of SO2, around 30 to 35ppm based on the estimated juice yield, but that's because I don't get a chance to see the fruit before it's crushed. I have not had problems completing ML using these low doses. All of the SO2 added pre-fermentation will be bound, but as @cmason1957 indicated, at some concentration even bound SO2 will have an inhibition effect on the MLB. I've seen 100ppm total SO2 published for ML inhibition, but it's variable, because MLB are inhibited by a combination of parameters which are additive including low pH, high ABV, SO2, low nutrients etc.

Cold maceration is usually in the range of 40F to 50F, once you get to 55F you'll start to see significant activity from ambient cold tolerant yeast like Kloeckera which is resistant to 70ppm SO2 and can generate ethyl acetate and acetic acid; a little activity some feel is desirable, but too much will be a flaw.

 

[MiBor]

I used White Labs WLP675 malolactic bacteria on a batch of Cabernet Franc from grapes in 2018. It was the slowest and most problematic ML fermentation I ever experienced. Slow to complete and very temperature sensitive, it took about 12 weeks to bring the Malic acid level low enough (chromatography) where I was OK to stop it and add SO2. I promised myself to never use anything other than Viniflora CH16 or Lalvin VP41. It's up to you if you want to use it, but there are much better options out there, that would save you a lot of headaches. I know that the price of dry ML bacteria is higher, but believe me, it's worth paying the price to have peace of mind that your ML fermentation will complete quickly and without problems.

 

[BI81]

Here's a link to an article on Morewine discussing a lot of what you all have mentioned (SO2 at crush, etc.)

How to conduct a Malolactic fermentation (MLF) | MoreWine

It's interesting that there is no mention of adding nutrient after rehydration unless you run into problems. I've always added Opti-Malo prior to inoculating and use Enoferm Alpha and haven't had any issues finishing MLF.

The one item I'm curious about is stirring during MLF, Morewine recommends stirring, but my understanding is that by not stirring you're lowering the redox potential which limits diacetyl production (which I have an extremely low threshold for and hate in any style of wine).

I'm curious about your approach to stirring, and if there are any factors that change your protocol? For example stir in glass vs don't stir in barrel due to oxygen presence, etc..

 

[cmason1957]

@MiBor I had heard of issues with the WLP675 from others also, so you are not alone there. I did a quick check of some of the other Malolactic Bacteria Strains SO2 tolerance, EnoFerm Alpha and Beta are both < 60 PPM, CH16 and VP41 are both < 50 PPM. That's why I always use one of those, no matter how much I have to inoculate.

@BI81 I stir my MLF's, but ever so gently, as I explained it to someone else one time, spoon goes in, down to the bottom and two or three very gentle times around the bottom of the carboy, that's all. I haven't noticed a high level of diacetyl production. I don't have a barrel, so I can only comment on carboy usage.

 

[mainshipfred]

I used it in 2 different wines when I was first starting. In fact I put 3 vials in one and 2 in the other and nothing happened. To be fair this was before I knew anything about the SO2 or brix restraints. Frankly aside for @MiBor's seemingly successful experience I haven't heard of anyone who had any luck with it. I really have to agree with the others and use anything else even though the cost factor may make it a little harder of a decision.

 

[BI81]

@MiBor I had heard of issues with the WLP675 from others also, so you are not alone there. I did a quick check of some of the other Malolactic Bacteria Strains SO2 tolerance, EnoFerm Alpha and Beta are both < 60 PPM, CH16 and VP41 are both < 50 PPM. That's why I always use one of those, no matter how much I have to inoculate.

@BI81 I stir my MLF's, but ever so gently, as I explained it to someone else one time, spoon goes in, down to the bottom and two or three very gentle times around the bottom of the carboy, that's all. I haven't noticed a high level of diacetyl production. I don't have a barrel, so I can only comment on carboy usage.

Anyone else not stir and have positive results? Always curious to hear others approach/results.

 

[RonObvious]

For single-carboy batches, I've always used Wyeast 4007 and never had a problem. I do not stir.

 

[MiBor]

I stir gently once a week during MLF. It keeps things going at a good pace. When I don't stir, I've noticed that the bubbling slows down and the process takes longer. I like to complete MLF in a glass carboy and then transfer the wine to the barrel, well sulfited and protected from oxidation.

 

[stickman]

I don't stir and haven't had any issues with slow ML. I think stirring is just a process that helps to ensure the ML goes without trouble; even if some diacetyl was generated during the process, it will be metabolized if the wine remains in contact with the lees after ML is complete.