Incomplete MLF

[keverman]

Looking for advice: It seemed like MLF was complete on my Marquette, tested complete with just those little test strips. I sent a sample to lab for full analysis for fun and to check my own testing skills on TA, etc.. Malic acid came back .5 g/l still, everything else looked good: 6.0 TA, 3.66 pH, low VA, residual sugar in dry range. An expert said I can either try and restart, or sterile filter before bottling and keep as is. Any experience or thoughts either way? (not sure how I would sterile filter...no equip for that) Interestingly Lodi lab gave me the same exact MLF reading on last years vintage. Wrong MLF bateria? (Alpha oenos)

 

[Ajmassa]

Alpha is legit. I used it with success. That’s weird. .5g/L is substantial (I think). I had a chroma last year show complete. But the strips showed about 30mg/L and 100mg/L. Never went farther. But as far as I was concerned if it wasn’t showing up on the chroma test then the malic left was minimal - regardless of what the mg/L were.
You trust their lab numbers? I’m suspect

 

[cmason1957]

.5 g/l is 500 mg/l, I had to go check, but that is as high as the malic acid test strips read. Which sort of sounds like no malic acid conversion. Is it possible that the malic acid test says .5 mg/l?? which I would consider a complete conversion, myself. Alpha is a good bacteria, I have used it also. Along with Beta, VP41, CH16, and CH Viniflora. They all worked just fine at converting, couldn't really tell much difference in the finished product.

 

[keverman]

Here is a clip of the Lodi Lab report: I was suspect too, especially since last year's sample read exactly the same on malic at 0.5 g/l and VA at 0.44 g/l. Seems scientifically unlikely that 2 different vintages are exactly the same on those readings?

The MLF seemed to progress very vigorously with LOTS of tiny bubbles for a good 2 weeks, then slowed but still there another 1 1/2 weeks.


Alcohol 13.18 %
Free Sulfur Dioxide
10 mg/L Total Sulfur Dioxide
14 mg/L Molecular SO2 0.14 mg/L
Residual Sugar 2.8 g/L
Malic Acid 0.5 g/L
pH 3.66
Titratable Acidity 6.00 g/L
Volatile Acidity 0.44 g/L


A2LA Accredited WI# 15 A2LA Accredited WI# 15 A2LA Accredited WI# 15 Calculation

WI# 15
A2LA Accredited WI# 15 A2LA Accredited WI# 15 A2LA Accredited WI# 15 A2LA Accredited WI# 15

 

[keverman]

Here is my strip....

 

[Ajmassa]

Heading down that rabbit hole now!
That’s a nice complete test you had done at Lodi. I did that once before to verify my ph meter. But the whole complete panel like yours woulda been expensive.
So your strip looks like 30mg to me— Or .03g/L — very similar color as the Chateaneuff du Pape strip I posted. And sounds like you had a textbook MLf visuals. I bet if you ran chromatography test it shows no malic too. Yet they say you’ve got .5g/L. U know what type of test was ran for the malic ? Usually they’re forthcoming. I know there’s multiple ways to get So2, RS, abv- but unsure about malic.
This is likely a bad suggestion, but if that was mine I think I would just continue on as if I never had the lab tests. You were on the gravy train until then. A trainee too scared to ask how the malic testing equipment works perhaps? Probably fills out .5g/L every time. And nobody has called him out yet. You know what you saw. And you see your strips. I’d go with my gut. Not the mystery lab work who claims your loaded with malic. They’re wrong. Not you.
In my opinion at least.—- <— my opinion and $2 will get ya a cup of coffee.

 

[keverman]

Thanks for the help! I'm feeling better about it. The Lodi test is a new one they have called "winescan". FTIR is the method listed and when I look that up, it's infrared scanning. $40 for the panel, which seemed like a bargain....perhaps for a reason?! I think I will trust the fact that it was looking like it was doing it's thing, and my strips look good, like you suggested.

 

[NorCal]

I was looking at historical time to completion of my mlf today. Around a dozen different wines over the past two years. Reds on CH16 took 45-60 days, whites with Beta took 90-115 days.

 

[Ajmassa]

Thanks for the help! I'm feeling better about it. The Lodi test is a new one they have called "winescan". FTIR is the method listed and when I look that up, it's infrared scanning. $40 for the panel, which seemed like a bargain....perhaps for a reason?! I think I will trust the fact that it was looking like it was doing it's thing, and my strips look good, like you suggested.

Infrared scanning? That’s cool. But $40 for all those tests would get me less than half the tests at my local lab done the ol fashioned way. So I’m still suspect. Especially because you did it last year too. And got the same exact numbers for malic and VA. Same grapes?
Please note that what I said could very well be terrible advice. I just wouldn’t want to create problems when there wasn’t one to begin with. Do you have access to chromatography? Not conclusive but would give another insurance. I would trust that more than anything at this point.
Did you pitch mlb during AF or after?

 

[keverman]

Same grapes and same ML bac. I know what you mean about the numbers matching. Seems unlikely. I pitched as soon as primary finished. I do not have access to chrome, I have also email lab and questioned them.

 

[Ajmassa]

At least your at a point where you can leave the wine sit while you figure it out.
Without a chroma then Waiting 2-3 months before racking and dosing So2 would be my move. Hell, I let one go an extra 4 months after chroma showed complete recently. Being topped up with a healthy ph there’s no reason to sweat the lack of So2 for that timeframe. Nothing to lose and would at least have peace of mind you didn’t prematurely stop your MLF.

 

[keverman]

Sounds like a good plan. Given my slight OCD (or is it dogged persistence? I'll keep poking around the issue to figure it out. Still waiting for some reply from the lab. I'll give a shout if I hear back from them. Thanks!

 

[Ajmassa]

Sounds like a good plan. Given my slight OCD (or is it dogged persistence? I'll keep poking around the issue to figure it out. Still waiting for some reply from the lab. I'll give a shout if I hear back from them. Thanks!

TBH I really thought there would be more members with experience chiming in with insight about this. I’m still pretty new myself. And I don’t know anything about that infrared technology. But I do trust chroma for progress and completion (to a degree). But yeah that’s what I think.

-With a complete chroma test- continue as you normally would

-without performing a chroma test— act as if MLf is still active for another 2-3months. Trying to keep temps up near 75°, stirring lees couple x a week, maybe even a half shot of opti-malo. Then maybe in January rack and dose with So2.

 

[Johnd]

Thought the conversations to date covered the topic pretty well, but my two cents: paper chromatography shows it complete, I’d wait 2-3 weeks, sulfite, and move on, regardless of the lab test. I trust my PC test way more than I do some lab tech mixing up samples or botching a test. PC don’t lie.

 

[sour_grapes]

TBH I really thought there would be more members with experience chiming in with insight about this. I’m still pretty new myself. And I don’t know anything about that infrared technology.

FTIR means Fourier Transform Infrared (spectroscopy). This a very common analytical technique in chemistry and physics. (My DW happens to be a world expert in this technique, but it is commonly applied in chem labs throughout the world.) It detects the presence of various molecules by shining an infrared light on a sample of your material, and quantitatively detecting how much infrared light is absorbed. The exact frequency of light that is absorbed reveals, with high specificity, what molecule is present, and the magnitude of the absorption tells you how much of that molecule is present. Under the correct conditions, it can be extremely sensitive. (In favorable cases, it is able to detect one part in ~10^8.)

I am not able to assess the relative reliability of the IR and chromatography results, unfortunately.

 

[stickman]

Most likely they are using this unit here https://www.gusmerwine.com/catalog/lab-equipment/winescan/

The lab is accredited for analysis using the FTIR unit, but I couldn't find anywhere the stated limits of detection for the listed parameters, which is the question that needs to be answered from lab personnel.

 

[keverman]

Thanks, all! I wanted to followup, since I did just hear from the lab. They just sent me the tech sheet for the winescan panel. I wish this would have been on the description page when I ordered it. Looks like the scan, while having good ranges for most of the tests, is limited in the malic acid test to the range of .5 - 5.0 g/l, so in both tests I was below the detection range. The lab tech described the test as having "poor resolution at the low end of malic acid and residual sugar".