Timeline for wine spoilage

[RottenGrapeJuice]

My Pinot noir is currently undergoing MLF, for which it will need to remain without sulfites for probably a couple months. I was wondering, if we assume you’re at a pH of 3.6 and 13ish percent alcohol, what kind of timeline are we talking for wine to start to spoil? Is it on the order of a few months or a few years? I’m sure it depends on your sanitation practices, but let’s assume the wine got infected. Basically I get worried whenever I do MLF that something will go wrong knowing that if I start to smell something, it’s may already be too late

 

[CDrew]

Spoilage for most intents and purposes, will depend on your ability to exclude Oxygen. The really bad spoilage organisms require Oxygen to make acetic acid or acetylaldehyde, and in it's absence, the acetobacter cannot grow. I'd be surprised if your MLF takes 2 months. So test starting at 2 weeks and get an idea. I'll bet you're done in 2-3 weeks if you inoculate during fermentation.

 

[mainshipfred]

Post fermentation MLF does take 2 months or so. I let mine go 2-3 months no matter what the chromatography says. The key is to keep the carboys topped up. My space is heated so the volume doesn't change with temp swings. I leave a 1/2 inch air space and never had oxidation issues.

 

[winemaker81]

As @Rice_Guy is (rightly) fond of saying, wine is a preservation system. As already noted, if you are using good hygiene and limiting O2 exposure, the timeline for wine can be years without sulfite. Sulfite is not strictly necessary.

However, I am not advocating no-sulfite unless one of the drinkers is allergic. Without K-meta the wine will oxidize sooner and spoilage organisms are more likely to hit. But in the short term, to promote MLF, the wine should be fine.

 

[Rice_Guy]

@RottenGrapeJuice, your post should be separated into tow questions 1) how long does microbial spoilage take? and 2) how long do changes in the chemical soup take to taste bad?

First, microbial spoilage can be totally eliminated by good sanitation and maintaining fences that prevent growth as alcohol and pH and low oxygen. Industrially we can be more sloppy and use only one fence as just filter at 0.45 micron or only pasteurize. . . . ie your microbial life can be measured in centuries/ how long till an event where the bottle busts.

Next oxygen is the enemy of alcohol. Wine can oxidize if it microbiologically sterile, if it is frozen, if it is contaminated with metals, and if it is treated with metabisulphite or SO2. Again oxygen is the enemy since it is one source of peroxide which promotes reactions where the soup is changed from reduced high energy molecules to more oxidized molecules. (We can measure the redox potential to put a number on the ratio of high energy molecules) Some companies have the technology where they press grapes under CO2 and flush hoses and tanks with nitrogen and package under a vacuum so they can build decades of shelf life without adding metabisulphite. I (and likely you) don’t have most of these technologies (I can vacuum package) so I would put the shelf life in weeks or number of times when the carboy was opened times the volume of oxygen which is introduced.
If you smell a defect it is too late! If the defect is below threshold level the redox potential tells me it is there and I could predict rate of change till an average consumer would smell it.
Your original post is looking for a number, ,,, YUP you should get months if the oxygen and copper and iron are excluded. The best number is months at a few times opening the carboy if you have minimal/ no oxidative headspace (use inert gas or 1cm ullage or vacuum) or one time opening the carboy if you have ullage at the shoulder of the carboy and fill it with air.

If you want to look more at the science I have posted what some of the experts say in the thread “a course”

This post evaluates ten webinars,, “BOOK REVIEWs” related to air exposure (AKA redox potential) while making wine. Negative as well as favorable quality changes are described for introduced oxygen. The selections are intended to present info about how and why flavors changes and what industry does (home winemakers could consider) to improve quality. .
- - - - - - - - - - - - - - - - -
An excellent first look at the effect of oxygen in a wines quality. It covers effects from a wide range of practices as tannin addition , splash racking, dissolved oxygen, temperature effects, gas/ nitrogen flushing and tools as oxygen transmission rate or the redox meter used to find where damage is happening, and what the change means on the finished wine’s flavor. Scott Labs like AWRI point at dissolved oxygen as the main culprit for loss of shelf life. A long video but the explanation to what can be improved; 1 hour, 38 min.
https://www.youtube.com/watch?v=ETuExGmNgzE * The Basics of Oxygen Management to Preserve Wine Quality: We are excited to announce the next episode in our new Scott Labs webinar series hosted by our very own Darren Michaels. Join us for a short presentation and Q&A with special guest speaker Luke Holcombe where we will be discussing the other side of finished wine quality: oxygen management. Topics will include: - What could go wrong? Oxygen-Related Faults - Bottling and Packaging Concerns - Oxygen Management Concepts and Techniques
- - - - - - - - - - - - - - - - - - -

This is a second look at oxygen exposure and risk analysis, again excellent. I found it interesting to have data which gave examples of what level of oxygen could be picked up in processes as racking or with a variety of closure types. I lust for one of the DO meters pictured. A final theme- we can extend wine quality into years by fixing at how much life we lose early in the winery processes. 1 hour, 7 minutes
https://www.youtube.com/watch?v=sn7Lxq4ynN4 * Dissolved Oxygen: Why it’s Important and how to Implement a Management Program: Luke Holcombe, Scott Labs Field Sales Rep., Dissolved oxygen is the driver behind many of the most common stability and spoilage issues facing winemakers. Its negative synergistic relationship with sulfur dioxide, the role it plays with volatile sulfur defects, and microbial interactions make it worthy of attention. In this webinar, we will discuss its effects, easy to implement mitigation and removal strategies, and discuss “bottle shock” as well as “barrel shock”.
- - - - - - - - - - - - - - - - - - - -

 

[Rice_Guy]

bacterial metabolism is dependent on the temperature, if the temp is marginal/ below 60F it can take till late spring when it warms up again.

. . . I'd be surprised if your MLF takes 2 months. .

 

[RottenGrapeJuice]

@RottenGrapeJuice, your post should be separated into tow questions 1) how long does microbial spoilage take? and 2) how long do changes in the chemical soup take to taste bad?

First, microbial spoilage can be totally eliminated by good sanitation and maintaining fences that prevent growth as alcohol and pH and low oxygen. Industrially we can be more sloppy and use only one fence as just filter at 0.45 micron or only pasteurize. . . . ie your microbial life can be measured in centuries/ how long till an event where the bottle busts.

Next oxygen is the enemy of alcohol. Wine can oxidize if it microbiologically sterile, if it is frozen, if it is contaminated with metals, and if it is treated with metabisulphite or SO2. Again oxygen is the enemy since it is one source of peroxide which promotes reactions where the soup is changed from reduced high energy molecules to more oxidized molecules. (We can measure the redox potential to put a number on the ratio of high energy molecules) Some companies have the technology where they press grapes under CO2 and flush hoses and tanks with nitrogen and package under a vacuum so they can build decades of shelf life without adding metabisulphite. I (and likely you) don’t have most of these technologies (I can vacuum package) so I would put the shelf life in weeks or number of times when the carboy was opened times the volume of oxygen which is introduced.
If you smell a defect it is too late! If the defect is below threshold level the redox potential tells me it is there and I could predict rate of change till an average consumer would smell it.
Your original post is looking for a number, ,,, YUP you should get months if the oxygen and copper and iron are excluded. The best number is months at a few times opening the carboy if you have minimal/ no oxidative headspace (use inert gas or 1cm ullage or vacuum) or one time opening the carboy if you have ullage at the shoulder of the carboy and fill it with air.

If you want to look more at the science I have posted what some of the experts say in the thread “a course”

Thanks for the info. I checked the MLF progress today with chromatography and essentially all malic acid was gone. Though, I still see many small bubbles rising to the surface. Should I wait until all bubbles stop before stabilizing?

 

[mainshipfred]

I would recommend waiting at least another 2 weeks after chromatography shows no malic. Chromatography is only a guideline and will show no malic even though it is still present. I don't remember the ppm that still may be present when malic is no longer showing up on the test.

 

[Rice_Guy]

Yes if you are satisfied with the taste after the MLF add metabisulphite, ,,, note! there is no one answer since you can be successful either way since the whole process is based on flavor.
Second note, the malic paper chromatography test has a detection level of (?) percent, “many” bubbles would indicate that it is actively out gassing, which suggests that a ferment is still happening. MLF and out gassing is very temperature dependent, and northern winemakers sometimes find that the tank shuts down till spring and warm temperatures, so we learn patience. ,,,, Again taste should be part of your decision point.

Thanks for the info. I checked the MLF progress today with chromatography and essentially all malic acid was gone. Though, I still see many small bubbles rising to the surface. Should I wait until all bubbles stop before stabilizing?