Kmeta

[cuz]

Sometimes I buy pasteurized juice from Festa. They include Kmeta in a 3.5g. packet. Since they provide kmeta premeasured in 3.5g packs, I figured that's the correct amount. So I measured 3.5g and added it to 6 gallons of fresh juice I am aging. Then I remembered that the rule of thumb is 1/4 of a teaspoon per 6 gallons. I converted 3.5g to teaspoons and it comes to about .8. So I think I put about 3x too much kmeta in my wine. It is still in carboys.

Two questions:

Did I put too much Kmeta?

Will it dissipate over time?

 

[Ajmassa]

hey cuz. looks like you pretty much answered your own question. Fermcalc says 3.5grams adds about 90ppm. still under the taste threshold. and the higher the ph the faster it will bind up and lower the so2 level. Tho high ph also means the higher minimum so2 ppm needed to protect the wine.

 

[cuz]

So I think what all that means is wines that have more acid (lower ph) need less kmeta? Or is it the other way around?

Either way will the so2 go away with time before bottling.

 

[NoQuarter]

I have not used this brand of juice before but have used others as well as Winexpert kits. Most kits I have made have a 3.5g packet that contains k-meta and sorbate in one pack. Not sure about pasteurized juice from Festa. Just a thought.

 

[cuz]

Interesting - the Festa packet is labeled KMS and the directions say it is potassium metabisulphite. I wonder if it is a combination of k-meta and sorbate in one pack. I am going to email them and ask

 

[user 36973]

So I think what all that means is wines that have more acid (lower ph) need less kmeta? Or is it the other way around?

Either way will the so2 go away with time before bottling.

Yes, wines with lower pH require less 'free SO2' to be effective. As @Ajmassa said, the sulfites tend to become bound to other compounds in the wine, removing them from the 'free SO2' group.

The sulfites will reduce in time as they do their job absorbing oxygen, binding up, or volatilizing. The chart above should be viewed as the minimum level of sulfites in your wine at all time. Redosing with sulfites at racking and prior to bottling to meet this is typical.

A rule of thumb I heard somewhere is that the sulfites drop by about 10ppm a month while aging and lower by about that much with each racking. If you have the equipment to measure free SO2 that is best, but rules of thumb work if you don't.

 

[cuz]

I started checking PH and SO2 levels a couple of year ago but gave it up. I think wine making should be fun and not feel a chemistry class (which I failed in HS). So if some of us are getting juice buckets (not fresh crushed grapes but refrigerated juice from vineyards), is it safe to say: 1/4 teaspoon of Kmeta for 6 gallons of wine, every three months is sufficient - without testing the PH.
Or maybe a different regiment. Say 3.5g on the first dose and then 1/4 teaspoon every 3 months.

 

[user 36973]

Yep, definitely some chemistry involved when you look under the hood. But rules of thumb can be applied so you don't need to make pH or acid measurements.

is it safe to say: 1/4 teaspoon of Kmeta for 6 gallons of wine, every three months is sufficient - without testing the PH.
Or maybe a different regiment. Say 3.5g on the first dose and then 1/4 teaspoon every 3 months.

Yes. The 1/4tsp in 6gal is about 30ppm, which is fine added every 3 months to maintain sulfite levels. Your first sulfite addition after fermentation should be double that amount.

 

[Ajmassa]

Interesting - the Festa packet is labeled KMS and the directions say it is potassium metabisulphite. I wonder if it is a combination of k-meta and sorbate in one pack. I am going to email them and ask

If that contained sorbate and they didn’t let u know that would be messed up. They say the combination of MLF and sorbate can ruin a wine. makes sense for kits since they don’t benefit from mlf. but juice pails do.
remember too the 3.5g of KMS might nit be all kmeta. camden tabs are kmeta but when measured after crushing they don’t equal the powder and probably contain some filler. Does the KMS packet fizz when added to the wine?

Festa one of the only one that adds yeast to the buckets too i read. or at least the only one transparent about it. Most of them are pre balanced for everything too. Brix, color, taste, acid/ph so no real need to get fancy with the chemistry on juice pails.

 

[cuz]

AJ-
The KMS packet does fizz when added to the wine. So far I can't contact Festa. I have enclosed the directions for Festa.

 

[user 36973]

You might be better off just buying the metabisulfite separately. Campden tablets or powdered meta is cheap and that way you know exactly what's in it. Same goes for buying sorbate rather than relying on purchased fpacs or wine "conditioner".

 

[swv]

KMS is Potassium-Metabisulfate.
https://fullforms.com/KMS/Potassium-Metabisulfite/10783

 

[mainshipfred]

As @Ajmassa mentioned 3.5 grams according to Fermcalc is 90 ppm in 6 gallons. My first dose after MLF I normally take it to 50 or 60 ppm. On another note I just weighed 1/4 tsp of K-meta and it averages about 2.3 grams which is equivalent to 60 ppm in 6 gallons. I was recently told that 1/2 of the dose gets bound immediately which one of these days I'm going to check for myself.

 

[Ajmassa]

AJ-
The KMS packet does fizz when added to the wine. So far I can't contact Festa. I have enclosed the directions for Festa.View attachment 70496

interesting. the stuff they supply could be a version of evervescent so2. Amount weighed out for a target ppm does NOT equal amount from powder form. They add K-bicarbonate which makes it dissolve on its own like Alka Seltzer.

Who knows. Instructions are nice if you know nothing. But IMO youve made enough wine where you’re probably better off tossing that paper and making it the way you’re used to.