Sulfite adjustment issue

[ldmack3]

I’m having a problem (Ithink) adjusting sulfites. If I add the amount of sulfites as instructed fromwinemakermag, another program or with a calculator I get nowhere near theincrease in SO2 I am expecting. ​

​

For example; Ph 3.51, current so2 is 21. Per allcharts and software to achieve molecular of .8 it should be 41 and I need toadd .8 g of Kmeta powder. I add it, retest next day using same aeration/oxidationmethod and it has only increased to 25.6. I have more examples of this and itdoes not seem to matter what the Ph is, I never get the increase expected.​

​

I've tested juice with a known SO2 level and I read very close to that as specified so I trust my testing.​

I know about half getsbound up but would think the formulas would take that into consideration. I’mreally down to this theory as I have used fresh chemicals to no effect.​

Is that it? I just keepadding until I get the level I need? Sounds pretty scary to me!​

Les​

​

 

[JohnT]

I would validate the way you are testing for SO2. Make sure that your readings are correct.

 

[ldmack3]

I'm open to suggestions as to how to do that.
Thanks

 

[JohnT]

I use titrates (those little glass vials) and do 2 tests to be sure of my readings. Many others have had little success with them, but I feel they work well for me.

 

[ldmack3]

Is that the compare the color to the chart?

Thanks

 

[Chiumanfu]

All the calculators assume that a certain percentage of SO2 is bound immediately. Most calculators use a value around 57%. This value can vary a lot from real life due to several factors.

-Age and condition of the KMETA is a big factor. It has a shelf life and will last longer if stored in a cool, dark, airtight container.

-Condition of the wine. Is it oxidized prior to adding the KMETA.

When I do tests with the vinmetrica and fresh KMETA, the results typically come very close to the calculated prediction.

Also, I suggest letting the batch sit for a few hours before redoing the measurement. For some reason, if I try to retest right after adding KMETA, the results aren't always as expected... not exactly sure why.

 

[JohnT]

These are glass vials that are under a vacume. You draw a sample into the vial until there is a color change. You then read the total volume in the vial and this will give you S02 in ppm.

 

[ldmack3]

Chiumanfu

These are all new batches not oxidized. I usually wait at least overnight before rechecking. It sounds like I have old Kmeta. I keep it in a sealed apothecary jar in a cabinet that stays at 63F.

I'll pick up some new tomorrow and give it a try.

John T
That sounds better than what I originally tried. Mix it and wait 5 min then compare the color to a chart. Too hard to tell.
What's the cost of that set up?

Thanks all

 

[ibglowin]

I would also try some fresh H2O2 and NaoH. Check your connections for leaks. Which A/O rig are you using? More Wine?

 

[ldmack3]

Yes it is the More Wine.
Pretty sure my connections are good. When I am setting up my indication flask it calls for 3-4 drops of NahO to reach the color change. I do get the color change with 3-5 drops so I believe my chemicals are ok.

I spoke with them and they believe either I've got old Kmeta or its binding.

He gave me the formula to check my SO2 to check my tester and ultimately my Kmeta:
1gr of Kmeta in 1 ltr water.
Take 100 ml of this and dilute to 1 ltr.
This should test 100 ppm

If it's binding I should see a greater increase with each addition as less and less gets bound.

I picked up some fresh Kmeta this weekend but have not had a chance to do any of the above.

Thanks very much.
Les