# Use caution when testing TA with ph meter



## REDBOATNY

I tested two finished wines for TA this weekend using sodium hydroxide and a ph meter. I needed to make adjustments before cold stabilizing. The results were almost double compared to pre- fermentation. 1.5 compared to .9.

I suspected the sodium hydroxide and went to buy "fresh". The shop owner told me it only has a 6 month shelf life. When I returned home, I re-did the test and got what I expected .9 TA on Diamond, .85 on Niagara.

I then checked the PH of the old and new Sodium hydroxide and got readings of 11.4 /old, 14.6/ new.

Now the question: Is a PH test of the solution an accurate test of freshness?


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## zadvocate

Interesting I just bought new Sh and my results were similar. I need new again


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## Runningwolf

This is the procedure for checking Sodium Hydroxide 

View attachment Sodium Hydroxide test.pdf


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## ibglowin

I am assuming you purchased either 0.1 or 0.01 Normal (N) NaOH from the Home Brew Store and not Concentrated (undiluted) NaOH. The stuff from your LHBS has been cut with water so in theory the 0.01N solution of NaOH has a pH of 12 and a 0.1N solution in theory has a pH of 13. 

Unless you have a very very expensive pH meter you won't get much better accuracy than this on a typical inexpensive pH meter at extreme (low or high) pH's




REDBOATNY said:


> Now the question: Is a PH test of the solution an accurate test of freshness?


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## BernardSmith

Runningwolf said:


> This is the procedure for checking Sodium Hydroxide



Can you use a pH meter (8.2) rather than the indicator to check for the amount of KaPH needed ?


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## ceeaton

Runningwolf said:


> This is the procedure for checking Sodium Hydroxide



Thank you for helping me solve one of my major issues with testing TA using NaOH. Nice that PI Wines had what I needed, ordered on Thursday night and had a box on my doorstep today before noon, very nice!


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## ceeaton

Just for giggles I tested my 0.2N solution tonight that I opened 10-29-16, it is now 0.185N. Tested the new 0.1N solution I had ordered from PI Wines and got 0.102N (pretty darn close, and I could have been a bit off with my syringe management (kids have had insulin pumps for some time now, no drawing for arm shots anymore, yea)). 

Thrilled I can now test and trust my NaOH solutions, thank you Dan!


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## bionerd

xxxxxxxxxxxxx


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## bionerd

xxxxxxxxxxxxx


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## jburtner

We must always test the tester and calibrate the calibrator - Have a glass of wine and adjust the attitude 

Cheers!
-johann


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## ibglowin

Actually the pH meter is the easiest and most accurate way to measure TA. Especially with red wine. You use a small amount of wine. Usually 10ml and then dilute it with distilled water (enough to cover the probe well) Usually 30-50ml or so. You can make your analysis more accurate if you bring your test water to pH 8.2 but your only talking about a drop or two of NaOH which is well within the noise of the analysis. Endpoint is 8.2 which is the endpoint of the Phenolphthalein indicator . Easy peasy with a pH meter.

 Titratable Acidity Testing Kit Instructions



bionerd said:


> NaOH is hydroscopic, meaning that it will absorb water from the environment over time, which will cause the concentration of the solution to slowly decrease over time. If you notice the pH decreasing or you need to add more NaOH to titrate the same recipe, you probably need new NaOH. If you keep it properly stored (air tight container) it will last longer, but probably should replace every 6 month (more often if you expose it to air often)
> 
> pH is a direct measurement of the concentration of the concentration of the hydrogen ion concentration (which can be used to determine concentration of hydroxide). If you have a 1N solution of NaOH, it should give a reading of 14 on a pH meter. But you do want to make sure that you have properly calibrated your pH meter. Some meters only have calibration settings for solutions of pH of 7 and 4, which makes the meter more accurate for measuring low pH values, but not as accurate for large pH values. The other thing to consider if the pH scale itself. A pH difference of 1 unit equates to a 10 fold difference in concentration. So if you starting pH when you first bought your NaOH was 14 and now is 13, you have 10 fold less NaOH than what you started with.
> 
> For using a pH meter, you can, but you get the same results as using an indicator (long explanation of science below if you are interested)
> You can use a pH meter for the titration, but this isn't really the easiest approach (I have done it both ways in lab). When using an indicator like phenolphthalein (the indicator that comes with most titration kits), it will change color once the solution gets to a pH around 8. Once you get to the equivalence point (where you have neutralized all your starting acid) the pH of the solution will quickly increase with additional base, which allows you to quickly see the change in color. If you were to do the titration with a pH meter, you would essentially be looking for the same rapid increase in pH. To accurately use a pH meter, you would likely need to use a larger volume of starting liquid to fully submerge the probe (and thus would use your NaOH solution more quickly). You would also need to constantly stir your solution (which you do anyway swirling the mixture when using indicator).


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## Hoxviii

ibglowin said:


> Actually the pH meter is the easiest and most accurate way to measure TA. Especially with red wine. You use a small amount of wine. Usually 10ml and then dilute it with distilled water (enough to cover the probe well) Usually 30-50ml or so. You can make your analysis more accurate if you bring your test water to pH 8.2 but your only talking about a drop or two of NaOH which is well within the noise of the analysis. Endpoint is 8.2 which is the endpoint of the Phenolphthalein indicator . Easy peasy with a pH meter.
> 
> Titratable Acidity Testing Kit Instructions



You touched on this, but for this to work you need to know and trust your pH meter and know that when it indicates 8.2 it actually is 8.2. Using the pH meter and using 8.2 as a fixed end point means you have to use distilled water, correct that water to 8.2, de-air your must sample, and even then you need to watch for the sudden ramp up of indicated pH as you perform your test.

If you aren't doing all of that, then it really wouldn't be any more accurate than a visual titration. All you need to do for a visual titration is to make sure your hydroxide solution is still good per the PDF up thread, and watch for the color change.

So for someone that can verify their equipment I can see using the meter being a good method, but if someone has any questions about their equipment (or doesn't know 8.2 needs to be verified) I can see this as giving someone a false confidence/false sense of security. Ya know, a "the meter says 8.2 so it must be 8.2!" when there's no shade of pink showing.


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## BernardSmith

But trying to find color change with some red wines is not always very easy. The 8.2 is good enough even if not so accurate as long as you also trust your taste buds. Knowing the TA does not in fact mean that your wine is acidic enough or insufficiently acidic or too acidic


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## ibglowin

How do you see pink in a red wine sample?

Trusting your meter is sorta a given here and that is why you always calibrate with buffer solution(s) before hand. I would trust a pH meter any day of the week over a totally uncalibrated eye. Especially when your testing red wine samples. As I said the difference between uncorrected distilled water and corrected distilled water is one or two drops of NaOH. Considering your probably using a 5 or 10ml syringe that also is in the noise level of the syringe your using which more than likely has a 0.2ml increment.


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## mikewatkins727

Runningwolf said:


> This is the procedure for checking Sodium Hydroxide



Where, may I ask, do you get the Potassium Acid Phthalate?


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## ibglowin

http://www.piwine.com/potassium-acid-phthalate-n10-solution.html




mikewatkins727 said:


> Where, may I ask, do you get the Potassium Acid Phthalate?


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## bionerd

ibglowin said:


> How do you see pink in a red wine sample?



If the color is dark you would want to dilute it with water till it becomes clearer. A 1:4 dilution would probably be sufficient. This wouldn't affect the amount of base that you need to add since you are still starting with the same amount of acid (just in a different volume).

With the dilute solution, the color change of phenylthalein should be really easy to see. It turns a vibrant pink. If you are worried about accuracy, using the same syringe would cause the same issues with the pH mediated titration. If you really want a good an accurate measurement, you should probably get a 1mL syringe.

Since it is an acid base titration, the pH should change really quickly with the addition of base to the solution after the equivalence point has been reached (you have neutralized all the acid). The color range change for phenylthalein is between 8 and 10, so it would occur right about when the pH is 8ish. 

I tend to like using the indicator more simply because I dont trust the pH meter that I have. When I was doing titrations in the lab, I had access to a really high end pH meter that had .01 accuracy and was calibrated over a larger pH range. The one I have now is "student grade" aka bought with a just finished school budget. I would say if you have a fancy pH meter and feel comfortable using it, definitely go that route. But if you have a cheepo meter and wanna be sure you are getting accurate readings, indicator based endpoints are good too if you dilute the solution enough to see a strong color change.


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## ibglowin

I'm going to take a WAG in that you have never done single TA analysis on a sample of wine?

FYI, You can get a very accurate pH meter for about $100-150 these days. With temp probe compensation as well as 0.01 accuracy.

I have 35 years experience in analytical chemistry. You certainly can have have your phenylthalein if that is what you prefer. The rest of us will happily be using our pH meters and getting an accurate result without shooting past the endpoint in less than 2-3 minutes with some experience.

Oh and if you were to use a 1ml syringe you would have to refill it between 5 and 10 times for a single wine sample......



bionerd said:


> If the color is dark you would want to dilute it with water till it becomes clearer. A 1:4 dilution would probably be sufficient. This wouldn't affect the amount of base that you need to add since you are still starting with the same amount of acid (just in a different volume).
> 
> With the dilute solution, the color change of phenylthalein should be really easy to see. It turns a vibrant pink. If you are worried about accuracy, using the same syringe would cause the same issues with the pH mediated titration. If you really want a good an accurate measurement, you should probably get a 1mL syringe.
> 
> Since it is an acid base titration, the pH should change really quickly with the addition of base to the solution after the equivalence point has been reached (you have neutralized all the acid). The color range change for phenylthalein is between 8 and 10, so it would occur right about when the pH is 8ish.
> 
> I tend to like using the indicator more simply because I dont trust the pH meter that I have. When I was doing titrations in the lab, I had access to a really high end pH meter that had .01 accuracy and was calibrated over a larger pH range. The one I have now is "student grade" aka bought with a just finished school budget. I would say if you have a fancy pH meter and feel comfortable using it, definitely go that route. But if you have a cheepo meter and wanna be sure you are getting accurate readings, indicator based endpoints are good too if you dilute the solution enough to see a strong color change.


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## bionerd

I will say that i am not a total idiot, I have a PhD (from the sciences and with that experience I'm pretty sure I know what a color change looks like). I'm here so that I can learn more about the process from other people, so you don't need to be condescending. I have gotten some great advice from other people that have been more welcoming and willing to have more of a conversation. I'm just saying that both can work. If you have a lot of money and want a super accurate process that's great, use your pH meter.


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## Tnuscan

At times I've wondered, if before electricity, if A/O might of still existed, but instead of an electric pump, like a bunch of guys blew into a little hose. When one was out of breath, the next guy tapped the shoulder of the guy waiting to blow next, then he took over, using a manifold of course.

I can just see these guys now, complaining about, how this little electric pump was going to put them all out of business.   

Then along came the pH meter. 

Edit: I use both, am I crazy or what? I'm waiting... @sour_grapes.


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## sour_grapes

Tnuscan said:


> At times I've wondered, if before electricity, if A/O might of still existed, but instead of an electric pump, like a bunch of guys blew into a little hose. When one was out of breath, the next guy tapped the shoulder of the guy waiting to blow next, then he took over, using a manifold of course.
> 
> I can just see these guys now, complaining about, how this little electric pump was going to put them all out of business.
> 
> Then along came the pH meter.
> 
> Edit: I use both, am I crazy or what? I'm waiting... @sour_grapes.



Totally not sure why you called me out, but here is the first thing that came to my mind about your amusing "manual" A/O scenario: What if one of the human bellows had lots of garlic with lunch? Would that affect the sulfite results?


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## Johnd

Simmer down scientists!! Whilst I am only a lowly engineer, I too have an opinion. 

For me, in my winemaking world, having now conducted, dare I say hundreds, of TA tests, my vote is unequivocally for the pH meter monitored titration. Others may do whatever they like, I use 5 ml of wine, slightly diluted with DI water, have an automatic stirrer, and I've yet to screw one up. It's super easy and the endpoint in reached visibly (meter reading) and audibly (it beeps for us old dudes). This is my opinion.


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## bionerd

John, what kind of pH meter do you use? The first one I got was kinda crappy, so I went old school :/


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## ibglowin

Great, welcome, nice to have you here! 

Didn't mean to be condescending but, you were telling people that using an indicator and your eye is more accurate that a pH meter which is just not true unless you have been doing that analysis for 10 years in a lab. 
pH meters have gotten really accurate and really cheap in the last 10 years or so making them the standard for testing acids not only in commercial wine labs but also for the home hobbyist as well.




bionerd said:


> I will say that i am not a total idiot, I have a PhD (from the sciences and with that experience I'm pretty sure I know what a color change looks like). I'm here so that I can learn more about the process from other people, so you don't need to be condescending. I have gotten some great advice from other people that have been more welcoming and willing to have more of a conversation. I'm just saying that both can work. If you have a lot of money and want a super accurate process that's great, use your pH meter.


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## Johnd

bionerd said:


> John, what kind of pH meter do you use? The first one I got was kinda crappy, so I went old school :/



I started out with a meter I purchased online for 25 bucks or so. Once I knew that the wine bug had bitten me and I was indeed infected, I stepped up to the Vinmetrica 300 system. 

It comes complete with all that is needed for testing pH, TA and SO2 in my wines, including different sized, graduated measuring pipettes, syringes,magnetic mixer, and a laboratory stand to hold all of the above in place as I titrate. Replacement chems are easy to come by and I replace all once every year just before the fall grapes come out.

The proper analysis and modification of pH and TA is important enough in wine to make the investment sensible for me. If I spend 1500 bucks on the best grapes I can find, I want to do the best job I can as a winemaker. Having already produced 1000+ bottles of wine using the Vinmetrica, the cost per bottle is already about what I pay for a cork.


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## jburtner

+1 on the meters. Get a couple $20 ones and eventually a nice one. Use them all and compare regularly with your calibration standards as well as ofher wines / etc....

Cheers!
-johann


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## Tnuscan

sour_grapes said:


> Totally not sure why you called me out, but here is the first thing that came to my mind about your amusing "manual" A/O scenario: What if one of the human bellows had lots of garlic with lunch? Would that affect the sulfite results?



LOL! I was being silly/funny, just finished a bottle, and was trying to bring in some fun. I'm still a kid at heart. Laughed myself to tears at "human bellows".


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## bionerd

ibglowin said:


> Great, welcome, nice to have you here!
> 
> Didn't mean to be condescending but, you were telling people that using an indicator and your eye is more accurate that a pH meter which is just not true unless you have been doing that analysis for 10 years in a lab.
> pH meters have gotten really accurate and really cheap in the last 10 years or so making them the standard for testing acids not only in commercial wine labs but also for the home hobbyist as well.



Very true, I can definitely see the utility of the meter for those who haven't been "lab rats" lol. My lab head was so completely old school, so he had us doing all the bio techniques from the 80's (worked great but took like 3 days compared to 3 hours) so I suppose I'm and old person at heart still trying to get with the current times


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## bionerd

Johnd said:


> I started out with a meter I purchased online for 25 bucks or so. Once I knew that the wine bug had bitten me and I was indeed infected, I stepped up to the Vinmetrica 300 system.
> 
> It comes complete with all that is needed for testing pH, TA and SO2 in my wines, including different sized, graduated measuring pipettes, syringes,magnetic mixer, and a laboratory stand to hold all of the above in place as I titrate. Replacement chems are easy to come by and I replace all once every year just before the fall grapes come out.
> 
> The proper analysis and modification of pH and TA is important enough in wine to make the investment sensible for me. If I spend 1500 bucks on the best grapes I can find, I want to do the best job I can as a winemaker. Having already produced 1000+ bottles of wine using the Vinmetrica, the cost per bottle is already about what I pay for a cork.



That system looks awesome!  I'm still in the "wow 75 dollars for fruit is pretty expensive" phase in life, but I can see that being a really nice Christmas present to myself once I start doing larger batches. You must have the wine cellar of everyone's dreams!


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## Johnd

bionerd said:


> I can see that being a really nice Christmas present to myself once I start doing larger batches.



Truth be told, I was pining over it for a few months, and Mrs. JohnD got it for me as a present, she's my biggest advocate!! Doesn't hurt that she loves wine too!!


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## bionerd

Johnd said:


> Truth be told, I was pining over it for a few months, and Mrs. JohnD got it for me as a present, she's my biggest advocate!! Doesn't hurt that she loves wine too!!



Now that right there is a keeper!!!


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## ibglowin

I still do free SO2 by aeration/oxidation. Very accurate, but time consuming to setup and run. My eyeball for the endpoint detection of course. The Vinemetrica was just coming out at the time I needed to purchase something and it was expensive (still is IMHO), used proprietary chems that were expensive as well so it was a no brainer (for me anyways) to purchase the $99 A/O Rig off Morewine. Chems are dirt cheap and you can be purchased locally for the most part or on the interwebs.

As for good pH meters that won't break the bank, Many here have purchased the Milwaukee brand of meters MW102 etc. and had great reliability. I purchased a Hanna pHep 5 meter 7 years ago and have had great reliability. Paid a whole $89 now up to just under $100 I see. 

I recently was starting to second guess my pH readings so I purchased some cleaning solution for proteins (grape, etc.) cleaned the probe retested, still was not feeling like it was right so purchased a new probe for like $50 from Hanna, popped it in and the new probe gave the exact same reading to 0.01pH unit once calibrated so you can trust them if you take care of them properly and calibrate them once a month or each time you use them.

Again, welcome we are glad to have you!



bionerd said:


> Very true, I can definitely see the utility of the meter for those who haven't been "lab rats" lol. My lab head was so completely old school, so he had us doing all the bio techniques from the 80's (worked great but took like 3 days compared to 3 hours) so I suppose I'm and old person at heart still trying to get with the current times


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## Ajmassa

Never in a million years would I think 2 chemists disagreeing about proper TA testing could be so captivating!
I've been testing using the titrate applicator kit. And solely going by it's included instructions, which are vague. I recently bought a $20 pH tester. So I just looked up the proper way to test TA with the meter. 
In doing so, I found that I may have been logging the color change incorrectly I think. My instructions called to add the NaOH and stir. But not to stop when a full color change was noted like I have also read. And to keep adding until the color continues to change even more. And stop when the color is no longer changing. I've read conflicting things on when to stop and note the amounts. And the conflicting instruction could differ more than .2% for results. 

Also, When using a ph meter and diluting a sample with distilled water (with or without adjusting ph to 8.2) are there certain things to account for since it was diluted ? 
Let's get wordy. Ill say it this way. Assume all samples same
-A 15 ml sample with 6 ml of NaOH added for color change is .60% TA
-A 15 ml sample with 6 ml of NaOH added to get ph of 8.2 is also .60%TA
-a 15 ml sample diluted with 30 ml distilled water would still only need 6 ml of NaOH for .60% TA ? Or wouldnitnbe more NaOH needed and there is an adjustment then made to account for this?
- and same for diluted water that was previously adjusted up to ph 8.2?


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## bionerd

I'll definitely look into the Hanna pHep 5. If it has been working well that long for you, that must be a good one!


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## ibglowin

I have done it both ways, (adjusted my distilled water to 8.2 and left it as is right out of the bottle) The difference is literally a couple drops using 0.1N NaOH. In fact the instructions for TA testing that come with the Morewine TA test kit have no mention of the need to preadjust your distilled water. Its really within the noise of the results. You won't taste any difference in a wine that has a TA of 6.5 g/L or 6.6 g/L in another words.


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## ibglowin

Some people (like me) have had great luck, others it has crapped out in a year or so. Maybe I got lucky, IDK but I have always cleaned it afterwords, stored it properly calibrated often just the usual stuff your suppose to do. YMMV as they say but it has been a good one for me. The Milwaukee is certainly more "old school" in nature using BNC connectors and all, but that design makes it also more clunkier and definitely calls for a more traditional setup of stand etc to hold the probe(s) etc. Where as the Hanna is waterproof and floats. Both probes are at the end of the meter and the pH probe is replaceable (plug and play)



bionerd said:


> I'll definitely look into the Hanna pHep 5. If it has been working well that long for you, that must be a good one!


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## Ajmassa

Ok. So bear with me. A 5 ml sample requires to multiply the NaOH amount by 1.5 correct?
And a 15 ml sample does not need any equation. So diluting 15 ml sample with 30 ml of water would yield (essentially) the same result? 
Just as diluting 5 ml sample would still just multply by 1.5?
All this assuming a .1 solution. Currently I've been using .2.


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## ibglowin

There are a bunch of different TA formula's out there so you have to be careful and use the right amount of wine and the right strength of NaOH or the formula will produce an incorrect answer. The water adds no acid (really) so it doesn't matter how much you add, it won't affect your result enough to matter.



Ajmassa5983 said:


> Ok. So bear with me. A 5 ml sample requires to multiply the NaOH amount by 1.5 correct?
> And a 15 ml sample does not need any equation. So diluting 15 ml sample with 30 ml of water would yield (essentially) the same result?
> Just as diluting 5 ml sample would still just multply by 1.5?
> All this assuming a .1 solution. Currently I've been using .2.


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## bionerd

Ajmassa5983 said:


> Never in a million years would I think 2 chemists disagreeing about proper TA testing could be so captivating!
> I've been testing using the titrate applicator kit. And solely going by it's included instructions, which are vague. I recently bought a $20 pH tester. So I just looked up the proper way to test TA with the meter.
> In doing so, I found that I may have been logging the color change incorrectly I think. My instructions called to add the NaOH and stir. But not to stop when a full color change was noted like I have also read. And to keep adding until the color continues to change even more. And stop when the color is no longer changing. I've read conflicting things on when to stop and note the amounts. And the conflicting instruction could differ more than .2% for results.
> 
> Also, When using a ph meter and diluting a sample with distilled water (with or without adjusting ph to 8.2) are there certain things to account for since it was diluted ?
> Let's get wordy. Ill say it this way. Assume all samples same
> -A 15 ml sample with 6 ml of NaOH added for color change is .60% TA
> -A 15 ml sample with 6 ml of NaOH added to get ph of 8.2 is also .60%TA
> -a 15 ml sample diluted with 30 ml distilled water would still only need 6 ml of NaOH for .60% TA ? Or wouldnitnbe more NaOH needed and there is an adjustment then made to account for this?
> - and same for diluted water that was previously adjusted up to ph 8.2?



I will start by saying I'm pretty new with wine making (and worked in an old school lab), so I have been treating this more as a "fun chemistry experiment" and using more of my understanding of science as a guide, so I defer to the master wine makers here




but this is essentially the acid base chemistry behind what you are doing:

If titrating wine is your first experience with titrations, I can definitely see how the instructions that come with the kit are not "user friendly." Especially if you are working with red wine where is says to look for a "greyish color" The first time I used that for undiluted cherry I honestly thought what is greyish???? But, if you dilute your wine so that it is only slightly pink, the color change will be a lot easier to see. One problem that people have (from my experience in the lab) is to over titrate. The indicator will change to a bright fuchsia pink once you have reached the end point of the titration, so that is where you would want to stop.

If you are good with indicator based titrations, you should reach the endpoint and have a pH around 8.2. Adding more water shouldnt change the endpoint of the reaction since you are still starting with the same amount of acid, just in a different volume. So you wouldn't need to make any adjustments there. If you are diluting, I would use distilled water or tap water. If you bring the pH of your diluting water up and add it, you are essentially making your starting fluid more basic, which can throw off the results titration (science opinion here, not sure if there is an impact on the wine making science).

For you, I would probably say that the pH mediated titration method would probably give you the best results since it takes the guess work of "did it change color enough" out of the titration. You will probably want to get a stir plate so that your pH meter is reading the pH of the solution (if not properly mixed, your meter could be measuring lower or higher than what the solution should be)

One fun experiment you could do (I plan on doing this too on my next batch to see if my questionable meter is as questionable as it seems) is to titrate with the pH meter but still add indicator. That way you can see what the endpoint would look like with the indicator based method, but still have the precision of the pH meter.


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## Ajmassa

Thank you kindly. The ph value of the water had me overthinking it. 

Edit. Thank you to both of you that is.


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## bionerd

I will say it's really awesome to have some chem nerds here!


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## bionerd

One thing I have been wondering is if its better to add acid before or after fermentation? maybe both? The fermentation produces CO2, which would combine with water to make carbonic acid (thank you to the person who reminded me of this). I know its not a strong acid, but would it dissociate enough to throw off the acid content in the final product? Or would applying a vacuum to degas afterward fix that? (Im probably over thinking this)


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## Tnuscan

Too acidic, can lead to a stuck fermentation and produce off flavors.


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## sour_grapes

bionerd said:


> One thing I have been wondering is if its better to add acid before or after fermentation? maybe both? The fermentation produces CO2, which would combine with water to make carbonic acid (thank you to the person who reminded me of this). I know its not a strong acid, but would it dissociate enough to throw off the acid content in the final product? Or would applying a vacuum to degas afterward fix that? (Im probably over thinking this)



Yes, the CO2 makes it more acidic, but we generally take that out of reds by degassing. Most winemakers leave a little residual CO2 in whites for a smidge more acid.


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## ibglowin

I personally think its better to add acid up front (at least with reds for sure) whites are a little less complex and seem to incorporate acid just fine even post fermentation. Post fermentation is nice as you know exactly what you have, not much guesswork like when you add pre-fermentation


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## Tnuscan

I agree with adding it, and getting it balanced in the primary, over done, and it gets the ball rolling in the wrong direction.

All things in order, where they need to be.


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## Ajmassa

This "acid adjusting up front" question is just personal preference and neither is 'better' with all depending on a lot of different variables right? Especially with equipment and work space as factors. 
Personally the 1st thought that comes to my mind is when adjusting before primary all the extra time needed. And adding and waiting and checking and adding...etc. I'm hesitant to let fresh pails go unrefrigerated for too long while adjusting. Pickup day is Yeast day for me. 
If you had to adjust the acid and wait and check, and if by chance you needed to add again and then wait and check, how long would that take? Shouldn't you be letting the acid additions sit for a day to get a proper reading? 
And related question, how long can you leave juice sitting w/o pitching yeast before problems could arise? (I don't sulfite until maybe a week or so after racking to carboy or demis)


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## Johnd

Ajmassa5983 said:


> Ok. So bear with me. A 5 ml sample requires to multiply the NaOH amount by 1.5 correct?
> And a 15 ml sample does not need any equation. So diluting 15 ml sample with 30 ml of water would yield (essentially) the same result?
> Just as diluting 5 ml sample would still just multply by 1.5?
> All this assuming a .1 solution. Currently I've been using .2.



With my Vinmetrica setup, using 5 ml wine, 15ml DI water, and .133 solution, the result is obtained by multiplying the amount (in ml) of solution used to reach pH 8.2 by 2. So if you use 3 ml in your titration to reach 8.2, the TA is 2 *3, giving 6.0 g/l, or .6%, whichever way you prefer to look at it........


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## ibglowin

This is the generic formula for using any sample size and any strength NaOH

TA as tartaric acid in *(g/100 ml (or %))* = *(V)(N)(75)(100)/(1000)(v)*

*V *= ml of sodium hydroxide solution used for titration 
*N* = Normality of sodium hydroxide solution 
*v* = sample volume (ml)


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## bionerd

Mike, just curious, what kind of chemist are you? I know you mentioned analytical chemistry, but your user name here is making me think radioactivity?


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## ibglowin

Like they I say, I could tell you but then........

Lets just say I don't necessarily make the boom. But I do make the boom better!


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## bionerd

HAHAHAHAHAHAHA That is awesome!!!


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## mikewatkins727

ibglowin said:


> Like they I say, I could tell you but then........
> 
> Lets just say I don't necessarily make the boom. But I do make the boom better!



Knows about you, Mike. I spent my time in the Air Force during the Cold War analyzing the other guys' junk to figure out how bad his boom was.


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## zadvocate

Assume I use .1 NaOH, If I tested a 5 ml sample and it took me 4 ml of NaOH to reach 8.2, (6g/l). Should the same wine with a sample of 15 ml need 6 ml of NaOH to reach 8.2?


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## ibglowin

No, it would require 12ml of NaOH to reach pH 8.2 for a 15ml sample.



zadvocate said:


> Assume I use .1 NaOH, If I tested a 5 ml sample and it took me 4 ml of NaOH to reach 8.2, (6g/l). Should the same wine with a sample of 15 ml need 6 ml of NaOH to reach 8.2?


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## Johny99

Mike is right. Look at it this way. A volume of liquid has so much "acid". Twice the volume, twice the "acid". So twice the base to neutralize it.

Yes I know my use of acid isn't correct but I figured it was simpler


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## zadvocate

Is it correct to multiply the amount of NaOH used to titrate the sample by the size of the wind sample? For example with a 5 mL sample you multiply the amount by 1.5. (that's with the instructions in my kit) I saw in this thread that someone said with 15 mL you can multiply by one. Just trying to understand the reasoning for that.


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## Johnd

zadvocate said:


> Is it correct to multiply the amount of NaOH used to titrate the sample by the size of the wind sample? For example with a 5 mL sample you multiply the amount by 1.5. (that's with the instructions in my kit) I saw in this thread that someone said with 15 mL you can multiply by one. Just trying to understand the reasoning for that.



Look at the formula Mike posted a few back. If you know some of the variables, they can be inserted into the equation and simplified. For instance, this is the Vinmetrica solution:

Calculate the TA value as:

TA (g/L tartaric) = (V *.133 * .75) / S

where 
V = mL Titrant needed to reach the endpoint; 
N = normality of the Titrant, 
S = mL sample. 

If you use 5 mL of sample as directed, and the Titrant is 0.133 N as supplied, then the calculation is simply:

TA = 2 * V (i.e. 2 times V) 

So if you use the.133 solution and 5 ml sample as I do, the equation above is applicable, and simple. You can insert your normality and sample size, solve the equation and come up with a factor based upon your parameters.


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## ibglowin

The reasoning is that the other parts the equation then just cancel each other out. 

And yes there is a formula in which you don't have to dilute your wine and it may use 15 ml sample size but it may use 0.2 N NaOH. Since I don't use that I don't have it off the top of my head. I don't wish to use 15ml at a time of my wine each time.



zadvocate said:


> Is it correct to multiply the amount of NaOH used to titrate the sample by the size of the wind sample? For example with a 5 mL sample you multiply the amount by 1.5. (that's with the instructions in my kit) I saw in this thread that someone said with 15 mL you can multiply by one. Just trying to understand the reasoning for that.


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## Ajmassa

ibglowin said:


> And yes there is a formula in which you don't have to dilute your wine and it may use 15 ml sample size but it may use 0.2 N NaOH. Since I don't use that I don't have it off the top of my head. I don't wish to use 15ml at a time of my wine each time.




Yes and yes. The Vintners Best kit I used calls for a 15 ml sample (hated pulling larger samples) and does in fact use .2 NaOH. So if it takes 6 ml of solution, then your TA is .6. Easy peasy


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