Hi I bought all the stuff I need but now I have lost my instructions. this is for a small batch of 5 gallons I have all the pipes, the PH metre, the naoh at 0.1N but no instructions and not equations to help can someone help thanks stef,Montreal.
Stef, here's how I do it; Pipet 5ml wine into a beaker. Add about 200ml distilled water. Standardize the pH meter. Place the pH meter electrode in the beaker with the sample. Record the starting volume of NaOH solution in the buret. Add NaOH slowly while stirring the sample. Stop when pH rises to 8.2. Record the end volume of NaOH. Multiply ml of NaOH used by 0.15. The answer is %TA.
Bill Frazier Olathe, Kansas USA
thank you sir. I don't have distilled water.... do you think I can use our city water? thanks stef
No, your city water will contain various minerals and chemicals to purify the water. These chemicals will interfere with the pH of your sample and throw off results. If you can obtain reverse osmosis water that will work like distilled water. In the US we can buy RO water in most grocery stores...also the distilled water.
Bill Frazier Olathe, Kansas USA
Most distilled water will affect pH as well. As soon as it is exposed to air (which usu. happens before they package it) it takes up CO2 and becomes slightly acidic. Test some and see. Not sure about RO water but I would suspect the same thing would happen.
Why do you need to dilute the sample anyway since you are not looking for a color change?
Miker - Grocery store distilled water does contain CO2 as you say. But, it does not significantly change titration results for winemaking purposes. You can boil and cool distilled water before titration but the results are not significantly different than if you just used the distilled water right out of the plastic bottle. The titration method I use calls for 5ml wine samples so I dilute with distilled water to make mixing easier and to submerge the pH electrode during the titration.
Bill Frazier Olathe, Kansas USA
I use a 10 ml sample of must but I do things a bit different.
I pull a 50 ml sample, take it to boiling and let it cool. I replace the lost volume which is usually less than 1 ml with distilled water. Boiling it drives out any CO2 in the sample. (You don't have to boil, I think 180 F is hot enough.)
I use 10 ml of this prepared sample for both pH and TA.
I calibrate the pH meter and record the pH, than add 0.1N NAOH until the pH is 8.2; I multiply the amount of NAOH by 0.75 to get TA.
Joe
William Frazier wrote:
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