I am going to run a titration with my burette using .1N NaOH to a Phenophtalene endpoint but have lost the equation to calculate the % tartaric acid. Despite my books and web articles I can't find it. Anybody have it written down? You know what I mean: x ml's of wine require x ml's of .1 NaOH equals the tartaric acid level. I also guide my adjustments with pH ( when I can get a sample to the lab at my job) and Taste of course. Thanks, Lou.
For a 5 ml sample of wine: multiply the cc of .1N NaOh by 0.15
Example:
4.8 ml of NaOh x 0.15 = 0.72%Note:
"For a red wine do not immediately add the phenolphthalein indicator as you would with a white wine or must. The red pigments make it difficult to see the end point unless you first titrate without phenolphthalein until the color turns the red to a blue of green. Only then will you add the indicator and then continue to the first pink that persists. If the sample is deeply pigmented you can dilute it with more distilled water which does not affect the result."
The above information from Presque Isle Wine Cellars
I can give you their method to standardize sodium hydroxide with potassium acid phthalate if you have some old NaOh and want to make sure it is still full strength and how to standardize if it is not.
Good site. In addition I think it is a good idea to have the formulae in the cellar along with pencil and paper since not all of us have a computer there. Also computers do fail - most often when you really need them. I have found out also, there is no substitute for a hard cover note book and make notes on paper. They can later be entered into your computer. I guess I am a little old fashion is some ways.
This brings up a related question. How long is NaOH solution good for?
Dick
Paul E. Lehmann wrote:
Hello Dick, My Analytical chemist gave my NaOH from 2006 and said it will be fairly close to .1N. It shouldn't make a big difference cause wine makers are going for a range anyway. Hope he is not wrong!
The best thing to do is have Presque Isle (piwine.com) send you the procedure for checking your NaOH. If it is weaker, you have the information to use to adjust the calculations. This works for open or closed containers of NaOH. If you had it stored in a closed container, it does not mean it is full strength.
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