# acid question



## zigzag65 (Jan 15, 2007)

i have a six gallon batch of wine i just started.i am using an acid titration kit.tested a sample today ,had to add 7cc of the sodium hydroxide to the sample. this is where im confused, what is the acidity of my wine and how much acid blend do i add to the must if any?(added 5 teaspoons from the start)


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## Steve (Jan 15, 2007)

A lot depends on your kit, strength of the sodium hydroxide, and how old the sodium hydroxide is.


I have a Crosby &amp; Baker Wine Acid Test Kit. If you followed the instructions in that kit you would multiply 7cc * .25 = 1.75% Tartaricwhich is about 3 times what you want it to be. You are shooting for around 0.6% Tartaric.


Like i said this is for the Crosby &amp; Baker kit, not sure which one you are using. One factor that can greatly affect the outcome of the test is the age of the sodium hydroxide. You need to keep a pretty fresh bottle around. I think it is only at full strength for 3 - 4 months.


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## zigzag65 (Jan 15, 2007)

thanks for the reply steve. i have an L.D. CARLSON KIT. the strength is 1/5 normal,and the kit is only about a week old. first time using it here.


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## geocorn (Jan 15, 2007)

LD uses a 1/5 normal while CB uses a 1/10 normal solution. I have been trying to determine the difference, but no one seems to have an answer. Maybe PeterZ will chime in on this thread. He seems to have chemistry down to an art form.


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## masta (Jan 15, 2007)

Anormal is one gram equivalent of solute (in this case sodium hydroxide) per liter of solution. So 1/10 normal is 1/10 of a gram equivalent per liter of solutionand 1/5 would be 1/5 of a gram equivalent per liter of solution.
The 1/5 N solution used by LD is twice as concentrated as the 1/10N used by C&amp;B


So zigzag65 your wine's TA is .70% . What type of wine is it?


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## Steve (Jan 15, 2007)

The man with all the answers. What formula did you use to get that? Or does this kit work totally different than mine.


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## masta (Jan 15, 2007)

The LD kits with the 1/5N solution of sodium hydroxide use the formula: for each cc of sodium hydroxide used to achieve the color change equals .10% TA.


7cc = .70% which also is 7 grams per liter


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## masta (Jan 15, 2007)

Steve said:


> A lot depends on your kit, strength of the sodium hydroxide, and how old the sodium hydroxide is.
> 
> 
> I have a Crosby &amp; Baker Wine Acid Test Kit. If you followed the instructions in that kit you would multiply 7cc * .25 = 1.75% Tartaricwhich is about 3 times what you want it to be. You are shooting for around 0.6% Tartaric.
> ...




Steve,


Are those instructions included in the kit written by C&amp;B or by someone else? The formula of 7cc *.25 = 1.75% does not make sense?


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## Steve (Jan 15, 2007)

masta,


They came with the kit. It says to take the amount of sodium hydroxide added to obtain a color change and multiply by .25 to get acid content in percent tartaric.


The kit also includes Phenolphthalein (acid indicator solution) you add three or 4 drops to the sample prior to adding the sodium hydroxide. Maybe this is what makes it different.


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## masta (Jan 15, 2007)

The acid indicator is the same as all the kits I have seen no matter what the concentration of sodium hydroxide included in the kits.


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## zigzag65 (Jan 15, 2007)

MASTA!!!! it's an elderberry wine made with dried elderberries. so is mine alright or is it a little high? thanks for the help masta.


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## Joseph1 (Jan 15, 2007)

The volume of the sample used in testing must also be considered when determining the titratable acidity. You can use the following formula:<?amespace prefix = o ns = "urnchemas-microsoft-comfficeffice" />

TA = 75 * V * C/VS

Where:

V = volume of sodium hydroxide needed to reach the end-point
C = concentration of sodium hydroxide used (0.1 normal or 0.2 normal)
S = volume of the sample of wine or must

For example: you have a 15ml sample of wine and add 12ml of 0.1 normal sodium hydroxide solution to reach the end-point.

TA = 75 * 12 * (0.1 / 15)
TA = 6.0

The acidity of the sample is 6 grams per liter (6 parts per thousand or 0.60%).


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## masta (Jan 15, 2007)

I think you will ok with it especially if you plan to back-sweeten. The addition of acid in the beginning as you did following a recipe is designed to get you to a specific target and the finial adjustment is better done with tasting it.


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## masta (Jan 15, 2007)

Joseph said:


> The volume of the sample used in testing must also be considered when determining the titratable acidity. You can use the following formula:<?amespace prefix = o ns = "urnchemas-microsoft-comfficeffice" /><O></O>
> <O></O>
> TA = 75 * V * C/VS<O></O>
> <O></O>
> ...






Thanks Joesph...the volume of the sample must be the reason why the calculation with the C&amp;B kit didn't make sense.


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## zigzag65 (Jan 15, 2007)

thanks joseph. and thanks again masta,i am planning to back-sweeten it. not that crazy about dry wines,like mine a little sweet.


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## PeterZ (Jan 17, 2007)

This is actually a more complex subject than it appears to us wine makers. There are several factors involved.

1) Concentration of the sodium hydroxide (NaOH). This can be expressed as "Normal (N)" or "Molar (M)". In the case of NaOH they are essentially the same, because NaOH is monovalent. 1 N NaOH is 40 g/L NaOH in water at 20C. (Don't worry about compensating for temperature - we don't need anything like that level of precision for winemaking. Who cares if your TA is 6.14330 g/L or 6.14820?)

2) "as" You can express acidity as anything - as HCl (hydrochloric acid), as H2SO4 (sulfuric acid), or in our case, as tartaric acid. The same sample will give you different numbers based on the "as" value.

The net result is that in the US we want a kit that expresses as tartaric acid, because those are the numbers we all use. After that, follow the equation in the kit, as they have worked out the math.

For the rest, g/L = parts per thousand. g/L x 0.1 = % (parts per hundred).


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## sangwitch (Jan 17, 2007)

PeterZ - thanks once again for a nice detailed explanation.


I'm about to purchase my first acid test kit. Any opinions out there about what test kit is the best to get?


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## masta (Jan 17, 2007)

The basic kit is all you need.


http://www.finevinewines.com/ProdDetA.asp?PartNumber=5400


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## Wade E (Jan 17, 2007)

That is what I use but I want to get the otherb test so I can check my
S02 also. I believe its the Titration tester and I believe you can
check both with it. Am I correct or only S02?


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## masta (Jan 17, 2007)

Yes the Acidometerby Vinoferm is designed to check both TA and SO2 but you need to buy theIodic (SO2) Solution for the SO2 testing which is sold separately.


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## Wade E (Jan 17, 2007)

What would you recommend as I already have the acid test kit and it
works fine for me. Would you just recommend the titrets test for S02 or
do you recommend theacidometer to do both and put the acid tester to
rest!


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## OGrav (Jan 17, 2007)

Let me know what works wade, I am interested as well as to how much sulfite sticks around. After I get some experience and a feel for how acid plays a part,I probably won't use it much after that.


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## Wade E (Jan 17, 2007)

Wont use what, the test or acid? Each one is a big part of wine!


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## OGrav (Jan 18, 2007)

Neither one Wade, the sulfite test kit. I doubt that testing for free sulfite every time is a necessity.


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## Wade E (Jan 18, 2007)

Do you make scratch Wines, if so you will need to check your acid.
Recipes are usually just a reference as to what someone used but this
could vary dramitically from the fruit that one person used to the
fruit you are going to use. You really dont need this if your sticking
to kits though unless you are going to modify the kit, maybe blending!


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