ph and ta testing

Discussion in 'Beginners Wine Making Forum' started by gordonm, Sep 21, 2017.

  1. gordonm

    gordonm Member

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    I have a PH meter and TA testing kit. My question is how do I correct a PH reading that is to low or to high? Same question with my TA reading. And when should this be done?

    Also, I have St. Pipen and Lacrosse which I blend. What would be a good PH reading and TA reading? I heard I should be around 3.5 ph for white wine.

    I also have Frontenac blanc was wondering what readings I should be looking for in this grape.

    thanks for any help, gordon
     
  2. Ajmassa5983

    Ajmassa5983 Member Supporting Member

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  3. gordonm

    gordonm Member

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    thanks, that manual was very helpful. Of course, I have all white wine but I assume everything applies. thanks again, gordon
     
  4. cmason1957

    cmason1957 Member Supporting Member

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    Oh that it was so simple PH down TA goes up. It certainly isn't a linear relationship and it seldom does exactly what you expect it to so always, always, always add half of what you think, see what happens, then add half again.
     
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  5. sour_grapes

    sour_grapes Victim of the Invasion of the Avatar Snatchers

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    Well, they also have one aimed at white winemaking: http://morewinemaking.com/public/pdf/wwhiw.pdf
     
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  6. hamidreza

    hamidreza Junior

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    TA test with PH meter

    i have a PH meter to run the TA test with it and have read some article in this regard but it seems a bit confusing.
    the general rule is that we have to add Naoh until PH reach to 8.2. and then the amount of consumed Naoh rules
    here comes the confusing
    1-how much sample we need to run the test some article says 5ml some 15 some 50 ml:slp
    2-and also i have read this sentence in the articles " the units for the TA in this calculation are: Number of grams of tartaric acid per 100 milliliters of juice." what doese it mean ? shouldn't TA determine total acidity of wine?so why only tartaric acid ? the other acids won't be calculate?:po
    3- even in some article i have read that we should not run the test with Must and we have to strain it and run the test on the clear juice. is it correct?:ft

    can any one make it clear to me please??:a1
     
  7. Stressbaby

    Stressbaby Just a Member Supporting Member

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    TA measures all acids, not just tartaric, but the results is expressed "as tartaric." One could also express the results "as sulfuric" and some other fields do use sulfuric as the standard, but since wine has tartaric, the wine industry uses that standard.
     
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  8. stickman

    stickman Veteran Winemaker

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    1 - The procedures and the associated formulas for the final calculation are based on sample size and concentration of NaOH etc. Many of these procedures are simplified for convenience as well as to avoid having to explain all of the chemistry, so if you want to use a particular procedure, you need to follow it closely.

    2 - TA is titratable acidity; the NaOH will react with "acid" and does not distinguish between the different acids present. Therefore the test cannot determine how much of each acid is present. Tartaric acid is the predominant acid in grapes, so most procedures are standardized to report as if all of the acid is tartaric.

    3 - The chemistry is not uniform in grape must. Some procedures suggest blending a sample of must and straining to attempt to simulate what will happen during extraction for a red wine, or a white wine if the skins were going to be included during fermentation. Having a significant amount of debris or solids etc. in the sample reduces the true sample size. For example, you measure out a 15ml sample, but you really have 12ml, the other 3ml is solids. The sample size is part of the calculation and will affect the accuracy of the result.

    Hopefully this helps.
     
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  9. hamidreza

    hamidreza Junior

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    :b thanks a lot, you made it much more clear . but i have still question regarding the measurement formula.
    i have read 2 way to measure which are :
    1- in 15 cc of sample after reaching to pH 8.2 each cc of Naoh is equal to 1 g /lit TA or .1%Ta (http://www.grapestompers.com/articles/measure_acidity.htm)
    it has a clear example which says if you used 6 ml Naoh total acidity will be 0.6% TA

    2- consumed Naoh amount divided by sample volume multiply to 0.75 ( the units for the TA in this calculation are: Number of grams of tartaric acid per 100 milliliters of juice.)

    now if we check previous method in this formula the answer will be 3 not 6 6/15*0.75 =0.3% Trtaric

    **- i have also downloaded and app named: Fermcalc (which i recommend to everyone to install it , its a wine calculator, ) when i put the amount of the first method in it the answer will be 0.3% tartaric or 3 g/l
    [​IMG]
    here is the link to see the screenshot of the app result:
    http://www.winemakingtalk.com/photo/acidity-test-2693.html


    so according to your explanation regarding the usage of tartaric acid a standard unit. there for the first method must be wrong .
    am i correct?
     
    Last edited: Sep 25, 2017
  10. Ajmassa5983

    Ajmassa5983 Member Supporting Member

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    Depends on what kind of NaOH you use.
    My original test kit came with .2 NaOH. Which requires 15 ml sample of wine. And 1:1. 6 ml of NaOH needed = 6.0 g/L titratable acid.

    Now I use .1 NaOH. Calls for only 5 ml of sample. (And can be diluted with distilled water without hurting results) And NaOH used x 1.5. So if 4ml of NaOH needed then * 1.5 = 6 g/L Titratable acid.
    Here's the reference I use. http://morewinemaking.com/public/pdf/W501.pdf
     
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  11. hamidreza

    hamidreza Junior

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    :b perfect
    i understood the point completely now every thing make sense
    thank you so much
     
  12. Ajmassa5983

    Ajmassa5983 Member Supporting Member

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    I just recently switched from .2 to .1 NaOH. There was at least one occasion where I was sweating my TA dropping like crazy. Glad I procrastinated on the adjustment, because I just forgot to multiply by 1.5
     
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