Adding K Meta into must before fermentation?

[Silva070]

I’ve read a few places that some will add kmeta to the must before fermentation to knock out any wild yeast or bacteria 24 hours before pitching yeast. Is this absolutely necessary? Are there any downsides to doing this or not doing this? I believe my last batch ended up a bit vinegary and I’m trying to prevent that with any measures I can take. I think the main culprit last time was headspace in the carboys but what is everyone’s thoughts on this?

thanks!

 

[winemaker81]

Adding K-meta ahead of time is not essential, but it does eliminate or greatly reduce a large number of wild yeasts and microorganisms. Commercial yeast in a good starter crowd out the competition, but K-meta eliminates most ahead of time. I've gone back-n-forth on the subject, but currently lean towards adding it.

If you had a large headspace for a long-ish period of time, that's probably the source of your previous problem. While it's impossible to verify, it's the most likely.

 

[VinesnBines]

I did not hit a batch of fig wine with kmeta before fermentation and I've regretted it because it has tasted vinegary from the start. The figs were frozen fresh and since figs split open on the tree, fruit flies apparently did their damage. If I do it again, I may hit the figs with kmeta before freezing and again when thawing for wine.
Like Bryan, I've gone back and forth but I'm not risking a batch with fresh fruit again.

 

[NorCal]

SO2 upfront is not only to keep the spoilage organisms at bay, but to also kill bacteria that could be present on the fruit. I see it as a way to have a clean starting point, before fermentation begins.

 

[Scooter68]

I'll definitely second NorCals comments. Unless you are dealing pasteurized or commercially prepared concentrates/fruits, K-Meta will help you avoid a bacterial infection of your wine must before the Alcohol level is sufficient to knock bacteria out. The three pillars of wine protection are the pH, Alcohol, and K-Meta/SO2. At the time you start your fermentation you only have the pH helping you so K-Meta addition as you prep a fruit based wine is an additional protection. You might not suffer without it but if you are making wine on budget, or making a large batch, ruining a batch is real kick in the head. I've lost 2 batches out of 50 and it's no fun.

 

[Silva070]

thank you all, it seems like based off of everyone’s experience it doesn’t hurt to do it and I might as well minimize the risk if I can. I started today with about 1/16 tsp per gallon and I’m waiting 24 hours before I pitch the yeast.

 

[Jovimaple]

The normal dosage is 1/4 tsp for 5 or 6 gallons, so you're a little high. I generally use 1 crushed campden tablet (the potassium version, not sodium) per gallon, and use 1/8 tsp of kmeta for 3 gallons. I find it easier to use the campden tablets if I am working with a gallon because I don't have anything smaller than 1/8 tsp and I am bad at guessing amounts!

 

[winemaker81]

1/16 tsp per gallon produces ~62 to ~75 ppm, whereas 1/4 tsp/5 gallons produces 50 ppm. The difference is not critical.

To avoid Campden, dissolve 1/4 tsp K-meta in 5 Tbsp water, then add 1 Tbsp to each gallon.

 

[CortneyD]

1/16 tsp per gallon produces ~62 to ~75 ppm, whereas 1/4 tsp/5 gallons produces 50 ppm. The difference is not critical.

To avoid Campden, dissolve 1/4 tsp K-meta in 5 Tbsp water, then add 1 Tbsp to each gallon.

Is there a reason one would want to avoid Campden??

 

[winemaker81]

Is there a reason one would want to avoid Campden??

No technical reason. They are a PITA to crush finely and are more expensive than powdered K-meta. I make very few small batches, so a bag would sit in a drawer for years.

A fair number of folks have posted that they are making numerous gallon batches, so making up a bit of solution and adding by the Tbsp is probably easier.

 

[barryjo]

I would say the difference between tablet and powder comes down to how much you would use in a years time. If you don't use much, tablets might be the way. And always put the purchase date on the container, regardless. This applies to all chemicals we use. They all have a shelf life.

 

[Rice_Guy]

I am surprised that no one has mentioned protecting flavor as a reason for adding meta/ Campden to white/ fruit musts. ,,, Red grape is pretty well protected, and I know a few people who never bother with meta on a red must.
Down side, commercial folks have a 200ppm maximum.

 

[balatonwine]

I’ve read a few places that some will add kmeta to the must before fermentation to knock out any wild yeast or bacteria 24 hours before pitching yeast. Is this absolutely necessary?

No, it is not necessary. It depends on the type of wine you want to produce.

The "natural" wine movement says to let the wine ferment "as is" given whatever microbiological community is on the grapes. Which I agree with if you have full control of the grapes from bloom to harvest.

If you do not have full control from bloom to harvest, then doing a natural ferment is fine if you fully know your grape source. And have some experience with natural ferment wine (it is more complicated than K-Meta wine which will mostly ferment with any added specific commercial yeast of your choice).

If you want to avoid issues, KISS (keep it seriously simple) or do not give a damn about this "natural ferment" stuff, then adding K-Meta at crush is perfectly okay.

I have done both. It does create a different wine. And getting the natural ferment right takes some experience. So wanting to do a natural ferment correctly, you may loose a few batches. But that loss may be worth it once you taste a natural ferment wine. It is up to you. You are the wine maker.

I like wines from both methods (and they are different). So I consider it a matter mostly of preference, ideology and taste.

Hope this helps.