Need to rack after adding tartaric?

[Ajmassa]

A couple quick acid questions that I couldn't find online.
1. Up until now any time I've corrected acid levels it has been leading up to a different points of the process that always involved a transfer soon after. If tartaric is added is it beneficial to rack off the sediment or ok to let it be if not transferring otherwise?
2. When testing for TA using .1 sodium hydroxide, I use 5mL sample and dilute with 10-15mL distilled water. But the pH drops .1 after diluting. Isn't the pH supposed to remain the same, and does this mean my tests are not the true levels? (My meter is just 1 decimal point)

 

[cmason1957]

Distilled water doesn't mean it has 0 Hydrogen Ions, it has a molar concentration of 10xx-7 ( as in 10 to the -7). So if you were really at 3.34 ph, I could see it bumping it up to read 3.4. It is why I have a 3 decimal point meter and ignore the last two, usually. But the difference between 3.3 and 3.4 is small enough to consider to be the same for winemaking (that right there is an opinion statement, not a fact YMMV).

And no, I don't always rack after adding, but I do mix the additions into some wine or water before adding and stir well.

 

[Ajmassa]

Ok Thanks. That's what I suspected. I didn't know if that was common for other people testing TA same way or not.

 

[ibglowin]

pH and TA are not the same measurement. You are using the same instrument to detect the same thing however (pH). With TA you are using your pH meter to read the endpoint 8.2 which is where all of your Titratable Acid has been reacted with your titrant (NaOH). So in theory if you want a more accurate TA result you should use water that has been adjusted to pH 8.2 (your TA endpoint). The reality is your only talking about ~one drop of NaOH to get your water to 8.2 (adjusted) depending on your water's pH. Your more likely to have that much (or more) error in your addition of NaOH trying to get to a perfect 8.2 pH and going over or under or not reading your syringe correctly. Bottom line adding distilled water to wine will change the pH of the wine and that is why you would not do that if you are interested in a wines true pH but you don't care about it when your running a TA analysis.

If you add Tartaric you should always wait to rack as you are adjusting the wines chemistry and you could have a resulting precipitate form and then drop out at some point so you don't want to be in a hurry to bottle after adjusting your wines TA or you could end up with a fair amount of precipitant (acid) falling out in a short amount of time.

 

[Ajmassa]

pH and TA are not the same measurement. You are using the same instrument to detect the same thing however (pH). With TA you are using your pH meter to read the endpoint 8.2 which is where all of your Titratable Acid has been reacted with your titrant (NaOH). So in theory if you want a more accurate TA result you should use water that has been adjusted to pH 8.2 (your TA endpoint). The reality is your only talking about ~one drop of NaOH to get your water to 8.2 (adjusted) depending on your water's pH. Your more likely to have that much (or more) error in your addition of NaOH trying to get to a perfect 8.2 pH and going over or under or not reading your syringe correctly. Bottom line adding distilled water to wine will change the pH of the wine and that is why you would not do that if you are interested in a wines true pH but you don't care about it when your running a TA analysis.

If you add Tartaric you should always wait to rack as you are adjusting the wines chemistry and you could have a resulting precipitate form and then drop out at some point so you don't want to be in a hurry to bottle after adjusting your wines TA or you could end up with a fair amount of precipitant (acid) falling out in a short amount of time.

The fact that the end result is barely affected answers my question. Originally using the term "true levels" was a mistake. I just wanted to make sure I wasn't getting faulty TA numbers since pH drops by ~.1 after diluting. I use a meter to 8.2 but still dilute for a bigger sample, as per morewine instructions here:
http://morewinemaking.com/public/pdf/W501.pdf

And as far as tartaric precipitate, i did intend on waiting. Racking or bottling too soon I understand. But I was concerned leaving the wine on that tartaric sediment for 2-3 months before the scheduled racking. And was just making sure that wouldn't negatively affect the wine.
So from your response I can assume that sediment from tartaric in there for a couple months will be fine. I didn't realize that the precipitate would continue dropping out beyond a week or so after the addition.

 

[ibglowin]

The longer it sits the easier it will actually be to rack the wine off of the wine diamonds as they will just get more and more solid. No harm to the wine at all.

 

[Ajmassa]

Good info. Thanks

 

[Smok1]

A couple quick acid questions that I couldn't find online.
1. Up until now any time I've corrected acid levels it has been leading up to a different points of the process that always involved a transfer soon after. If tartaric is added is it beneficial to rack off the sediment or ok to let it be if not transferring otherwise?
2. When testing for TA using .1 sodium hydroxide, I use 5mL sample and dilute with 10-15mL distilled water. But the pH drops .1 after diluting. Isn't the pH supposed to remain the same, and does this mean my tests are not the true levels? (My meter is just 1 decimal point)

My kits different, mine says use a 15ml sample and dilute with 15ml distilled water and the ph doesnt change at all when adding the water, im using sodium hydroxide (1/5n) not sure what that equates to in a percentage.

 

[Ajmassa]

Yea it's all about which type of sodium hydroxide is being used. Whether .1 or .2 and .01 I think all call for small variations.
I originally had a .2 kit as well. But multiple tests pulling 15mL samples got to be annoying. The .1 only requires 5 mL sample. And also less solution. Instead of mL's NaOH added being your TA with the .2 , the .1 is mL of NaOH added x 1.5.