I can't measure my TA~!

[Delaney]

Hi,

I purchased a TA testing kit. It comes with sodium hyrdoxide, and phenolpthalein.The instructions are to add 3 drops of phenolpthalein (color indicator) to 15ml of wine must. Then to slowly add sodium hydroxide.

1cc=1gram/liter

The instructions mention that the color will suddenly turn grey. I've tried this three times now and the color does not turn gray suddenly, it turns grey very gradually. after 20CC of sodium hydroxide, the must still looks red when I shine light through it, but if I pour it out of the vessel it appears grey/black.

I was adding the sodium hydroxide .5CC at a time.

What am I doing wrong here??? The wine must is a purple/red color. I gave up and began fermentation, but I'd like to figure out what I was doing wrong so that when I reach FG I can measure and adjust my TA.

The wines being produced are red raspberry wine and black raspberry wine.

 

[ibglowin]

This is why everyone uses a pH meter to read the endpoint for TA analysis. There is no question about the endpoint.

Are the chemicals fresh (as far as you can tell) and were you swirling the mixture the whole time you were adding NaOH?

 

[Delaney]

This is why everyone uses a pH meter to read the endpoint for TA analysis. There is no question about the endpoint.

Are the chemicals fresh (as far as you can tell) and were you swirling the mixture the whole time you were adding NaOH?

I got screwed when I initially bought the kit. the sodium hydroxide was dated to 2009. Then I bought a sodium hydroxide separately, but the manufacturing date is not provided on this other bottle.

I'm starting to think I wasted $15.

 

[SBWs]

Like said pH meter is a lot easier, however if you don't have one try this. Dilute the sample with 45 ml of distilled water (will not affect the result). Some other tips; do test on white background in well lighted area, Make up 2 samples so you can compare colors between the two.

If you are still having problems; First add NaOH until color starts changing now add the 3 drops of phenolphthalein indicator then continue adding NaOH three drops at a time, stirring in between, until color doesn't change.

 

[SBWs]

Remember there are 2 types of NaOH sold for acid testing. 0.1 and 0.2 make sure you know which you are using, it make a big difference in the results.

 

[djrockinsteve]

Like said pH meter is a lot easier, however if you don't have one try this. Dilute the sample with 45 ml of distilled water (will not affect the result). Some other tips; do test on white background in well lighted area, Make up 2 samples so you can compare colors between the two.

If you are still having problems; First add NaOH until color starts changing now add the 3 drops of phenolphthalein indicator then continue adding NaOH three drops at a time, stirring in between, until color doesn't change.

you beat me to this. definitely do the test in a well lit area.

someday when you can buy a good ph meter @100 bucks. not only can you quickly test your ph but with only 1 chemical you are able to test for the amount of acid in your wine.

check the tutorial section for some other assistance in tests.

 

[Dougxox]

tried to do a test on some norton last year, wine was too thick and dark to get a reading anywhere near where it should be. even tried diluting it. waiting for a pH meter...