Add KMeta on Third Racking?

[vinividivici]

I've got a couple of carboys of Carmenere and Malbec. On the second racking from the secondary to carboy on the Carmenere, I added 1/4 tsp of KMeta per rec of one of the posters here.

I'm getting ready to rack once more for another six months, so should I add more KMeta or was the previous 1/4 tsp enough?

Thanks,
Bob

 

[robie]

The previously added 1/4 tsp will get you through the next six months, but the SO2 level at the end is very likely to be very, very low. What you really need is a SO2 tester setup, so you will know for sure.

You didn't say when you added that 1/4 tsp of Kmeta.

If you can't test free SO2, if you recently added that Kmeta, I would wait for 3 months and add 1/8 tsp, not 1/4. By the end of the 6 months, you will be ready for another 1/8 tsp.

 

[shoelesst]

The previously added 1/4 tsp will get you through the next six months, but the SO2 level at the end is very likely to be very, very low. What you really need is a SO2 tester setup, so you will know for sure.

You didn't say when you added that 1/4 tsp of Kmeta.

If you can't test free SO2, if you recently added that Kmeta, I would wait for 3 months and add 1/8 tsp, not 1/4. By the end of the 6 months, you will be ready for another 1/8 tsp.

I don't agree that the SO2 will necessarily last six months, especially since he is racking. Racking can introduce a lot of oxygen depending on how it's done and this can deplete SO2 quickly.
Testing is always the best answer, but I think it' also safe to say that after introducing oxygen through an activity like racking, it is safest to sulfite.

 

[vinividivici]

So Shoe,

Would you add 1/8th tsp of KMeta before racking this last time? Again, it will be in the Carboy for another six months.

Thanks,
Bob

 

[winemaker_3352]

I don't agree that the SO2 will necessarily last six months, especially since he is racking. Racking can introduce a lot of oxygen depending on how it's done and this can deplete SO2 quickly.
Testing is always the best answer, but I think it' also safe to say that after introducing oxygen through an activity like racking, it is safest to sulfite.

If you are vacuum racking - there won't be much SO2 escaping out - as there is not a lot of O2 introduced..

 

[shoelesst]

If you are vacuum racking - there won't be much SO2 escaping out - as there is not a lot of O2 introduced..

Agreed , depending on how the racking is done the amount of oxygen introduced will be different. If racking by siphon and not by vacuum, then I would add 1/8 or 1/4 tsp of sulphite.

 

[altavino]

what is your ph?

above 3.7 I would add 1/4 tsp
3.6 or lower 1/8 tsp.

 

[vinividivici]

what is your ph?

above 3.7 I would add 1/4 tsp
3.6 or lower 1/8 tsp.

Don't know yet. I've got a new pH test kit and will use it for the first time with this racking. Thanks for the info.

Bob

 

[altavino]

is it strips or a meter? the strips are pretty useless for red wine.

if you haven't got acurate PH numbers , I would assume if your brix was above 24.5 you PH is also above 3.7 and add the 1/4 tsp.

if aging in a small barrel , which will eat up free so2 faster than a carboy , I'd go with 1/4 tsp

if you have an accurate means of measureing ph , then match PPM of so2 with PH.
and ignore the 1/4 and 1/8 tsp reccomendations.

here is an so2 addition calculator
http://www.vinoenology.com/calculators/SO2-addition/

then you can manage so2 like a pro, ph meter in hand.
Ph meters start around $60 bucks .

 

[vinividivici]

is it strips or a meter? the strips are pretty useless for red wine.

if you haven't got acurate PH numbers , I would assume if your brix was above 24.5 you PH is also above 3.7 and add the 1/4 tsp.

if aging in a small barrel , which will eat up free so2 faster than a carboy , I'd go with 1/4 tsp

if you have an accurate means of measureing ph , then match PPM of so2 with PH.
and ignore the 1/4 and 1/8 tsp reccomendations.

here is an so2 addition calculator
http://www.vinoenology.com/calculators/SO2-addition/

then you can manage so2 like a pro, ph meter in hand.
Ph meters start around $60 bucks .

I've got a meter/reagents for pH measurement. And thanks for that link, very helpful!

Bob

 

[vinividivici]

is it strips or a meter? the strips are pretty useless for red wine.

if you haven't got acurate PH numbers , I would assume if your brix was above 24.5 you PH is also above 3.7 and add the 1/4 tsp.

if aging in a small barrel , which will eat up free so2 faster than a carboy , I'd go with 1/4 tsp

if you have an accurate means of measureing ph , then match PPM of so2 with PH.
and ignore the 1/4 and 1/8 tsp reccomendations.

here is an so2 addition calculator
http://www.vinoenology.com/calculators/SO2-addition/

then you can manage so2 like a pro, ph meter in hand.
Ph meters start around $60 bucks .

I calibrated the digital meter, and the test reading is 3.09 at 62 degrees F.

I looked at the calculations on the vinoenology site, but not sure what to do next. I plugged values into the "SO2 Addition as Potassium metabisulfite (K2S2O5)" (5 gallons of must, .5ppm target addition) and wound up with .02 gms to add.

Is this an insignificant addition, meaning don't add anything as the juice is near the proper pH and SO2 levels?

Bob

 

[altavino]

do you mean 50ppm ?

 

[vinividivici]

do you mean 50ppm ?

No, the chart references on the site show a target of 0.5ppm mg/l. That's what I was quoting. Obviously, my problem is attempting to equate my pH with the required level of SO2 in the juice.

 

[shoelesst]

No, the chart references on the site show a target of 0.5ppm mg/l. That's what I was quoting. Obviously, my problem is attempting to equate my pH with the required level of SO2 in the juice.

That is Avery low pH. I would even say it is outside the normal range of 3.2-3.6. The lower the pH the less SO2 required. Since you are so low, that is the reason you are a very low input requirement of sulfite.

I have never dealt with a pH that low, so someone else may be able to assist you in dealing with it.

Wait a minute - I just read again, Altavinom is right, usually 50ppm is what is the goal. I'm wondering if there is a typo in there. Interesting. Not sure what to say.

 

[vinividivici]

That is Avery low pH. I would even say it is outside the normal range of 3.2-3.6. The lower the pH the less SO2 required. Since you are so low, that is the reason you are a very low input requirement of sulfite.

I have never dealt with a pH that low, so someone else may be able to assist you in dealing with it.

Wait a minute - I just read again, Altavinom is right, usually 50ppm is what is the goal. I'm wondering if there is a typo in there. Interesting. Not sure what to say.

Shoe, not sure what you're saying about the "very low pH"? My reading of 3.9 is HIGHER than the normal range of 3.2-3.6, meaning it's toward the base side, not the acidic side of the range.

Re the .5ppm SO2 target, I''ve taken that right from the web site (link) Altovino provided.

Hopefully he can clarify all this.

 

[GreginND]

Shoe, not sure what you're saying about the "very low pH"? My reading of 3.9 is HIGHER than the normal range of 3.2-3.6, meaning it's toward the base side, not the acidic side of the range.

Re the .5ppm SO2 target, I''ve taken that right from the web site (link) Altovino provided.

Hopefully he can clarify all this.

In your previous post you said the pH was 3.09 which is very low. If it actually is 3.9 I would consider an acid addition.

I can see how the website would be confusing. You need 0.5 ppm molecular SO2. That is not the same as the free SO2 which is a combination of molecular SO2 and bisulfite. The equilibrium of the two is related to the pH. At higher pH more of the SO2 is in the bisulfite form and less in the molecular SO2 form. Thus you need more free SO2 to achieve the protective level of molecular SO2.

For example, to achieve a molecular SO2 level of 0.8 mg/L in a wine at pH 3.5 you need 40 ppm of free SO2. In a wine of pH 3.9 you need free SO2 if about 100 ppm to get the same 0.8 molecular SO2.

I hope I haven't confused you more.

This PDF provides some more information: http://www.accuvin.com/pHSO2Links.pdf

 

[GreginND]

Let me add that I think when you calculated that you need 0.02 g of k meta to get 0.5 ppm so2 I think you were confusing molecular o2 with free so2. At your pH you need something more in the range of 50-75 ppm free so2.

Unless you have a way to test the actual free SO2 I would not complicate the situation. If I were you, given he high pH, I would add 1/4 tsp kmeta at each racking and call it good. I don't think it would be adding too much. If your nose or taste buds tell you differently I would adjust that lower.

 

[vinividivici]

Greg (and Shoe and Altovino),

You are right. The pH WAS 3.09. Too many damn numbers floating around in my 3-cell brain.

Okay, so now the pH is very low. Do I need to add bicarbonate or something to bring it into the desirable range before worrying about the SO2 level?

BTW, the juice is Carmenere if that helps.

I plugged in the correct pH of 3.09 into the calculator and it now shows a desired level of 10.03 mg/l SO2.

Thanks,
Bob

 

[GreginND]

I don't think I would try to adjust the acid by chemical means. How does it taste? Did this wine undergo mlf? It may be difficult if you have already added sulfite. You could try to cold stabilize it to drop out some if the tartaric acid.

 

[vinividivici]

I don't think I would try to adjust the acid by chemical means. How does it taste? Did this wine undergo mlf? It may be difficult if you have already added sulfite. You could try to cold stabilize it to drop out some if the tartaric acid.

It has a slight bite to it but I attributed that to it being six months old.

Re MLF, I didn't know that it needed that. That's another gray area for me.

Re kmeta addition, I was following the advice of a board member to add 1/4 tsp at final racking before bulk aging in the carboy, which is what I did. I'm now ready to rack once more, ergo the initial question of how much kmeta to add.

The carboy is in my wine cellar at ~ 58 degrees. Does that meet cold stabilization temp?

Thanks,
Bob