I am really confused about PH / TA now

[toddrod]

I did a search and did not find a clear answer.

For the last 10 yrs or so I have made my muscadine and other country fruit type wines without using any acid testing and they came out fine. The last 2 yrs I started using the test tube type acid test kits and tested for TA and adjusted with acid blend. Now, this year I bought a PH meter to make it easier to test but now I am really confused with the whole PH / TA thing as I will explain.

Specifics : Hanna PH meter calibrated with fresh solutions. Fresh bottle of NAOH 0.1%. Fresh pressed juice from 2 different muscadine varieties.

Techniques used - 10mls juice. Add 0.1 NAOH until PH 8.2 obtained. Multiply mls of NAOH X .75 to get TA. (As listed in the Tutorial section)

Muscadine - Pineapple variety - PH 3.28 / TA .23
Muscadine - Ison variety - PH 3.14 / TA .3

So, if I were to do a pure juice wine and using the recommendation of getting the PH to 3.3-3.4 (as seen numerous times on the forum) I would have to raise the PH of the juice from 3.2 & 3.14. By doing this would I not also lower the TA which is low in both juice sample already?

The opposite of this is that I would have to increase the TA (I normally get my semi sweet wine to .5-.6 level) which should also lower the PH level even more.

As you can see I am confused to what number I should be titrating my additions of acid to. Either the PH or TA. I am happy to just get in the righ ball park for the numbers, which ever is right.

On another note, what is better to use, Tartaric acid or Acid Blend for this?

Any help on this would be appreciated

 

[ibglowin]

Your off in the pH/TA relationship.

If you add acid, your pH will "lower" meaning more acidic (think 3.2 --> 3.1) and your TA will RISE (think 0.5 -->0.6) meaning you have more acid in your wine (makes sense since you added more acid right?)

So one number goes down, one goes up.

Problem is it doesn't always work that way, sometimes one goes down and one doesn't change. There is a whole lot of chemistry going on (buffering compounds) in that little sample.

I have never worked with Muscadine so no idea what you want to shoot for (realistically) Sometimes you have to choose one value over the other or find some happy medium between the two.

If you have 10 years of experience with your taste buds I would trust them and look around for what others have shot for pH/TA wise with Muscadines. Also not sure if you should use acid blend or just tartaric acid with muscadines.

 

[MalvinaScordaad]

So, if I were to do a pure juice wine and using the recommendation of getting the PH to 3.3-3.4 (as seen numerous times on the forum) I would have to raise the PH of the juice from 3.2 & 3.14. By doing this would I not also lower the TA which is low in both juice sample already?

The opposite of this is that I would have to increase the TA (I normally get my semi sweet wine to .5-.6 level) which should also lower the PH level even more.

What you are saying is correct. But something troubles me. I don't make Muscadine much less with Pineapple. But Muscadine is a red grape so I will assume that it would be next to impossible to have a ph of 3.14 and have only a TA of .3 In most red grapes with a Ph in that order you would at least have a TA of .6 And any PH lower than 3 has to be pretty sour. I wouldn't get caught up in raising PH or lowering it for a few tenths but the TA is odd by itself. As far as Acid blend is concerned I know it is used in fruit wines but it does contain Malic which is something you don't want to add to grape wine ever.


Malvina

 

[ibglowin]

Wait, I think I see your problem.

Your factor with 0.1N NaOH is not 0.75 but 1.5. That will effectively double your TA results.

 

[whackfol]

I think the .75 factor is correct when using a 10mL sample. 1.5 is for a 5mL sample.

 

[MalvinaScordaad]

Wait, I think I see your problem.

Your factor with 0.1N NaOH is not 0.75 but 1.5. That will effectively double your TA results.

Yes!
and a better sample which is easier to measure would be 5 ml of juice and 100ml of distilled water ml of Naoh used times 15
Malvina

 

[robie]

I think the .75 factor is correct when using a 10mL sample.

I just looked at the tutorial and it says 10 ml sample, ml of 0.1 solution used multiplied by .75.

So which is really correct for 10ml of wine - .75 or 1.5?

I also like adding some distilled water, so the sample is more manageable.

 

[MalvinaScordaad]

I think the .75 factor is correct when using a 10mL sample. 1.5 is for a 5mL sample.

This is what I use
Malvina

 

[ibglowin]

Morewine Manual is

0.1NaOH
5ml wine sample
Factor is 1.5

 

[ibglowin]

Yep,

Didn't see he used 10ml sample size. Got all excited........

I think the .75 factor is correct when using a 10mL sample. 1.5 is for a 5mL sample.

 

[ibglowin]

Maybe the OP will pop in and confirm or deny the actual sample size at some point.......

 

[toddrod]

Sample size is 10mls as listed in original post

 

[SBWs]

Some ideas:

Use a 15ml sample, that is normally enough to cover the meter probe.

When using a 15ml sample and 0.1 NaOH the results will be half the amount of NaOH used.

Be careful when using distilled water, unless you check it first with your pH meter and it has a pH of 7.0. Any other pH will change test results.

(check NaOH and make sure it is 0.1 and not 0.2)

 

[MalvinaScordaad]

Be careful when using distilled water, unless you check it first with your pH meter and it has a pH of 7.0.

You really can't check the PH of distilled water as the PH meter cannot read it correctly since there are no ions in distilled water for the PH meter to use.
Malvina

 

[ibglowin]

Adding distilled water is common practice in TA analysis. If you really want to be a stickler you can bring your water to 8.2 first, then add your wine to it and do your TA analysis. There are so many other places where errors can be introduced it is hardly worth the effort though.

 

[Rodnboro]

Toddrod, I know this post is late, but I'm having the same issue with my muscadine. My first must (bronze)had a ph of 3.15 with a t.a. of .3. On this one, I added acid to get my t.a. up (only to .45) and when fermentation was finished, the t.a. was 1.0. My black muscadine (second batch) started a little better with a ph of 3.25 and t.a. .4. I didn't add acid but when fermentation finished, the t.a. also was 1.0. I'm at a loss and am just going to wait it out to see how they turn out.

 

[Turock]

todrod---maybe I can make this simple for you. We make more fruit wines than grape wine. And what we do is pay attention to the PH and ignore the TA. Especially when working with all fruit and no water, you've got to get your PH in line or else the wines will be too acidic. To raise PH on wine, don't use water. Use calcium carbonate. On pear or apple wine, you may need to lower the PH and acid blend works very nicely.

Actually, when we make Niagara grape wine, we use acid blend to lower the PH and it works very nicely. That little bit of citric acid in the blend really does a nice job on Niagara. So on certain grapes, you may find acid blend works better than tartaric.

 

[winemaker_3352]

Adding distilled water is common practice in TA analysis. If you really want to be a stickler you can bring your water to 8.2 first, then add your wine to it and do your TA analysis. There are so many other places where errors can be introduced it is hardly worth the effort though.

What is the actual purpose of adding distilled water to the must sample when testing TA/PH?

Is it just to get the volume level up to fully submerge the electrode??

Does this affect the ending result of the PH/TA readings?

 

[SBWs]

Most of the time when people add distilled water to the sample it's because they are looking for the color change of the sample during the acid test. This can be very hard to see in a red wine, deluding it with distilled water gives it as lighter color to start the test. If you are using a pH meter and adding Sodium hydroxide (NaOH) to 8.2 then I know of no reason to use distilled water because you don't need to see a color change.

 

[robie]

Is it just to get the volume level up to fully submerge the electrode??

Yes, if you are using a pH meter, it is good to get the level (volume) up a little, so the electrodes are submerged..