Free SO2-Bound so2

[fygunes]

Hi Everyone

The wine in barrel ant tank I used potassium metabisulfite in Wine Making.I made a test , get the result of free so2 level. I added SO2 again, but I retested and the SO2 levels were the same.

I suspected that all the SO2 is bound up due to aldyhyde formation(oxidation of alcohol), spoilage microorganisms or introduction of solids.

I checked the VA, but did not see any risk.

I am reluctant to keep adding the Metabisulfite for fear of over concentrating. Any help would be greatly appreaciated.

What should I do now in order to save the wine and unbind the so2 (for free so2)?

 

[Turock]

You can't "unbind" the bound SO2. You are correct when you say a portion of it binds to micro organisms--and oxygen, acetaldehyde, yeast, and sugars. The remainder remains as "free."

What is the PH of this wine and how much free SO2 do you have?

 

[ibglowin]

How are you testing for SO2?

 

[fygunes]

pH TA SG
3,62 5,18 991

The free SO2 is less than 5ppm. I am using aeration/oxidation method to determine free so2

 

[SBWs]

How experienced are you at doing the aeration/oxidation test?

Things that stick out without knowing how much wine you and talking about and how much K-meta you have added so far are:

Are you sure you are using 0.01 normal Sodium Hydroxide (NaOH) and not 0.1 normal?

Have you done this test on a known sample with correct results?

Are all your chemicals fresh?

My experience is the first time I add K-meta about 1/2 can bind after that the amount that becomes bound is a lot less each time I add it about 90 to 120 days. If you were at 5ppm and you added K-meta and it tested 5ppm again I'd suspect the test results. That is unless it was a large volume of wine and very little k-meta added.

 

[fygunes]

Volatile acidity: 0,54
The wine volume:1350lt kept in 15hl tank. but I use generally nitrogen for removing oxygen from the top of the tank.

I began suspecting due to the borne-Microorganisms. I will rack the wine to a 11hl tank, and then the res will be taken to demijeans and barrels.


I am experienced in lab.

Do you suggest anyhing too?

 

[Turock]

With that PH, you need about 50-55 PPM of free SO2.