TA titration test

[celladwella]

So tried taking an acid test TA. Since I didn’t have my testing kit at the time I crushed the grapes I took some of the must and put it into a bottle in the freezer. I thawed it out and used that. For some reason it’s not working out. The instructions say to take 5ml of wine add to the beaker, add distilled water until 2/3 full( so you can better see color change. Then put 3 drops of phenolphthalein indicator into it. Then draw 10 ml of sodium hydroxide this is
.1N. Did all that color changed to magenta shortly after adding a small amount and shaking vial. I got thru all of the SH and it never turned grey or green like it’s supposed to.

I also tried the Ph meter which is supposed to be more accurate and after adding around. 2 ml of the SH it shot over 8.2 so I give up unless some has something to add.

 

[GreenEnvy22]

Hard to say on the TA kit without seeing the instructions. The one I use doesn't sound quite like yours. With mine you take about 15ml sample of the wine/must, add 3 drops of pheno. Now start adding the SH in 1ml increments, stirring the solution in between. you'll see it temporarily change colour when you drip in the PH, but it will change back to the wine colour until you eventually get to the point it stays that other colour. How ever many mL of SH you added is how many g/L of TA you have.
Mine does say you can mix 15ml water with the 15ml of must/wine initially to make the colour change more evident if you have a dark wine.

As for pH meter, I've read about the procedure you're trying to do with the pH meter to calculate TA, but never tried it so can't offer any help.

 

[celladwella]

Hard to say on the TA kit without seeing the instructions. The one I use doesn't sound quite like yours. With mine you take about 15ml sample of the wine/must, add 3 drops of pheno. Now start adding the SH in 1ml increments, stirring the solution in between. you'll see it temporarily change colour when you drip in the PH, but it will change back to the wine colour until you eventually get to the point it stays that other colour. How ever many mL of SH you added is how many g/L of TA you have.
Mine does say you can mix 15ml water with the 15ml of must/wine initially to make the colour change more evident if you have a dark wine.

As for pH meter, I've read about the procedure you're trying to do with the pH meter to calculate TA, but never tried it so can't offer any help.

Thanks anyway

 

[stickman]

If you had the must in the freezer then you have to really warm it back up, not just thaw, put all of the must into a pan and warm up with constant stirring. Tartrates precipitate out when the must is frozen and they don't re-dissolve easily, so getting a uniform sample is difficult.

 

[celladwella]

If you had the must in the freezer then you have to really warm it back up, not just thaw, put all of the must into a pan and warm up with constant stirring. Tartrates precipitate out when the must is frozen and they don't re-dissolve easily, so getting a uniform sample is difficult.

Thanks that might be it. I was frustrated and dumped it out I did realize there was sediment on the bottom I’m thinking that maybe this is what happened.

I’m currently running MLF on my wine once that is done would I still be able to test the acid and ph or will it be useless to know at that point just wondering. Thanks for any input.

 

[Johnd]

Thanks that might be it. I was frustrated and dumped it out I did realize there was sediment on the bottom I’m thinking that maybe this is what happened.

I’m currently running MLF on my wine once that is done would I still be able to test the acid and ph or will it be useless to know at that point just wondering. Thanks for any input.

You'll be able to test at any time you like, just make sure that your sample is at room temps and completely gas free, as CO2 in the wine will skew readings by a pH meter.

 

[celladwella]

You'll be able to test at any time you like, just make sure that your sample is at room temps and completely gas free, as CO2 in the wine will skew readings by a pH meter.

Thanks John D. What is the method used for degassing a sample?

 

[Johnd]

Thanks John D. What is the method used for degassing a sample?

My testing only requires a small amount, which I put in a test tube with a cap and shake it up, release gas, shake, release, etc.... a few times until there is no more gas being released.

 

[celladwella]

Okay that what I’m going to try thanks