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silverbullet07

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I purchased a PH tester and calibrated it with distilled water and the ph buffer powders. It passes the calibration and then went to test the distilled water. I was expecting a PH 7.0 however it was reading a PH of 5.8. So that worried me and started researching. I found that after a couple hours the distilled water absorbs carbon dioxide which reacts with the water to produce carbonic acid, which in turn releases hydronium ions into solution. After two hours it absorbs all the Carbon Dioxide it can to produce it's final PH which is around 5.8.

Fun to learn something new.

Tested my filtered well water and it's PH is 7.4 . It has a special media filtration that removes iron, sulfur, bacteria, heavy metals. Our water taste really good and do not have any issues with it so I am hoping it will be good to add to our wine.

Getting closer to starting my fist batch.
 

BMarNJ

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I purchased a PH tester and calibrated it with distilled water and the ph buffer powders. It passes the calibration and then went to test the distilled water. I was expecting a PH 7.0 however it was reading a PH of 5.8. So that worried me and started researching. I found that after a couple hours the distilled water absorbs carbon dioxide which reacts with the water to produce carbonic acid, which in turn releases hydronium ions into solution. After two hours it absorbs all the Carbon Dioxide it can to produce it's final PH which is around 5.8.

Fun to learn something new.

Tested my filtered well water and it's PH is 7.4 . It has a special media filtration that removes iron, sulfur, bacteria, heavy metals. Our water taste really good and do not have any issues with it so I am hoping it will be good to add to our wine.

Getting closer to starting my fist batch.
I was worried about the same thing because my distilled water was not coming in at pH 7.. but my real worry is the test i use from morewine.com for TA. You put 5 ml of wine in a container, top it off with distilled water, then test for TA by adding drops of 0.1N sodium hydroxide until you reach a pH of 8.2 in the solution. Doesn’t the pH of the distilled water affect this test?
 

silverbullet07

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If that is the test you use with your PH tester, you should not top off your wine with distilled water. You add some drops of 0.1N sodium hydroxide straight to the wine and you keep testing until you reach 8.2. Then use a calculation to determine your TA level.
 

BMarNJ

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Was thinking that, but the calculation is based on 5ml of wine. I’d need more than that to get the tester wet, so the amount of sodium hydroxide would have to change too. Was thinking that I could use 15ml of wine then divide the amount required for the change by 3 to get the value, you think?
 

sour_grapes

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Follow the MoreWine instructions. What you are not understanding is that pH is a logarithmic scale. The test is calibrated to titrate the number of ions in 5 mL of wine (i.e., the acid). There are essentially NO ions in the water you add (compared to the number in the wine). So it doesn't really matter whether the pH of the water you add is 5 or 7, nor is the volume of added water that important. The base you add will still have to titrate the same number of ions from the wine.
 

BMarNJ

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Follow the MoreWine instructions. What you are not understanding is that pH is a logarithmic scale. The test is calibrated to titrate the number of ions in 5 mL of wine (i.e., the acid). There are essentially NO ions in the water you add (compared to the number in the wine). So it doesn't really matter whether the pH of the water you add is 5 or 7, nor is the volume of added water that important. The base you add will still have to titrate the same number of ions from the wine.
Thanks @sour_grapes , thats what I needed to understand. The fact that you use a pH meter to find the endpoint of the test was confusing me. .. and the fact that my TA was pretty low took me down that rabbit hole.
 

silverbullet07

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Was thinking that, but the calculation is based on 5ml of wine. I’d need more than that to get the tester wet, so the amount of sodium hydroxide would have to change too. Was thinking that I could use 15ml of wine then divide the amount required for the change by 3 to get the value, you think?
Their test most be Little different. I was following this youtube video. He was explaining the process well.
 
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Rice_Guy

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Yes CO2 can change pH , ,,,, HOWEVER ,,,, a system with no salts buffering it will show dramatic swings with little input.

,,, ex.sparkling water. , , , pH With CO2 3.5. pH without CO2 7.2 (a non buffered system consisting of carbonated city water and natural organic flavor)
 

CDrew

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Diluting the wine with distilled or deionized water just makes the sample easier to handle if you use a stir bar and a lab stand. The reasons it doesn't affect the pH titration is well explained by @sour_grapes . Also the size of the wine sample doesn't really matter either, as long as you know it precisely. The proprietary methods like Vinmetricas, use odd concentrations of the titrant, in order to simplify the math, and make sure you have to buy chemicals from them. But if you are not afraid of multiplication and division, just use standard concentrations and your pH meter. The equation takes into account the amounts of wine and concentrations of your solution. It just so happens that 5-10ml of wine works well with 0.1N NaOH. I load up a 50 ml burette with titrant and can run 4-5 titrations in 10 minutes. It takes longer to set up and clean up.
 

BMarNJ

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Their test most be Little different. I was following this youtube video. He was explaining the process well.
The test is basically the same but you only use 5 ml of wine and then you don’t need as much sodium hydroxide to achieve the end result. I’d rather add the distilled water and use less NaOH, since its cheaper and easier to come by.
 

silverbullet07

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Can you post the instructions and the calculation? I would like to give it a try.
 

AaronSC

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I have the "Vinmetricas" system that, as folks have pointed out, takes the "math" out of the the equation. You use 5ml of wine, diluted, and measure the delta of the Sodium Hydroxide from start to finish and multiple it by 2 (ok, there is some math). They set things up so that the concentration of Sodium Hydroxide they provide allows this to be simple. It also beeps when you reach 8.2 :)

I am thinking of switching to using 15 ml wine samples and standard Sodium Hydroxide 0.1 solution because it's has better resolution. The 5 mL sample saves on Sodium Hydroxide but gives coarser readings, since the impact of each drop is so much more.

I actually don't know how much more accurate this would be, but I think it would be reasonably more accurate. I'm also thinking of weighing the syringe empty, before and after to better calculate the delta, since eye-balling it is very coarse as well.

Am I being a bit crazy here? :)
 

Rice_Guy

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The first question is what concentration of sodium hydroxide can you buy?
Can you post the instructions and the calculation? I would like to give it a try.
The version I am running takes 0.2 normal NaOH:
1) measure 15 ml of sample into a test beaker(cup)
2) rinse the pH probe with distilled water, mix the juice with the probe, read the pH when it is stable and record this number as sample pH
3) fill a 10 ml syringe with NaOH and then drop liquid into test juice while swirling
at pH 6 mix till stable, at pH 7.5 change to a add one drop followed by swirl till stable procedure
4) stop when the pH is 8.2 and read the volume of sodium hydroxide
5) wash the head of the probe with distilled water (a sprayer bottle helps)
6) calculation: TA (percentage) equals volume titrant x 0.1
, , or ml volume titrant equals TA as grams per liter
.61B927C7-EDAA-45FD-AF40-BE3C837340E8.jpeg
Other:
*you need enough liquid to submerge the head of the probe, distilled water is transparent, but don’t use bottled drinking water or steam distilled baby formula water with minerals added
*I will reduce the sample size for high TA materials and then put a multiplier in the formula to correct back to a 15ml sample.
*this procedure is convenient in good part because Wine And Hops sells the chemical, but there is no magic to it, when I was in the QA lab the chemicals would have to be made and then the formula corrected for normality of NaOH, ,,,, ie the first question is what concentration of sodium hydroxide can you buy?
*the main use of the info for me is to build a target TA when formulating a fruit wine using natural food rules, ,,, ie no acid blend from the chemical jar
*most red juices will turn blue at pH 6 which tells you to slow down how fast you add reagent
*with most juices (pH 4 or less) I will add ten drops then mix it in with the probe to speed the titration, for me mixing is a one handed operation and syringe is a one hand operation
*syringes are available at the pharmacy for dosing meds for kids, I currently have 5 ml syringes
 
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