ph help

[harleydmn]

Just picked up my cab franc grapes, checked ph at 4.5 and ta at.65. What do I need to do and how much to add to adjust the ph down to 3.5 for 6 gal of must?
I got a sg of 1.084, how much sugar should I add to get about 14%? I think I need to stick to kits, chemistry was not my subject. Thanks for all the great help here on the forum.

 

[altavino]

I'd check your ph again

4.5 is very very unlikely at 6.5 TA.

One or the other reading is out to lunch.

 

[altavino]

Here are some handy winemaking calculators

http://vinoenology.com/

 

[ibglowin]

Are these from CA or East Coast? Agree with altavino, check your battery and make sure it is good and calibrate with fresh standards if you have them.

 

[harleydmn]

California, the ph is correct but had a hard time with the ta. new to taking these test. the ta could be off, the instructions said it should turn gray but it was gray from the start. I kept adding solution and it turned pink. Sorry for being such a newb but I am trying to learn.

 

[ibglowin]

Are you using your pH meter to check for endpoint?

 

[harleydmn]

No, using the ta test kit.

 

[ibglowin]

You need to use your ph meter to test for endpoint. What is the Normality of your NaOH?

The pH meter takes all the guess work out of it Harley. You titrate your sample to 8.2 on the pH meter. there is a formula that is simple to use once you know your Normality (strength) of NaoH.

 

[harleydmn]

Hey Mike,
0.10 I need to figure out how to do this with my ph meter, Can anyone explain it to me so a dummy could understand it?

 

[GreginND]

To titrate using your pH meter you simply need to add the NaOH solution slowly until the pH reaches 8.2. That is the same pH that your phenolthalein solution will turn pink.

I start with about 50 mL distilled water - add a drop or so of the NaOH until the pH is at 8.2. Then add my wine sample and titrate back to 8.2.

 

[ibglowin]

Use a 5ml sample of must. Add to your container. Add 50ml distilled water.

Get your syringe and fill it up with your NaOH and get out the bubbles and get the plunger lined up with the 5ml mark or 10ml mark as usual.

Drop NaOH in and swirl well to mix up. It will go pretty slow at first and then very fast at the end so go slow at the end (drop, swirl,drop, swirl....)

End point is 8.2 on the meter.

Formula if your using 0.1N NaOH and a 5ml sample size is:

1.5 X (ml of NaOH used) = TA in G/L

Hey Mike,
0.10 I need to figure out how to do this with my ph meter, Can anyone explain it to me so a dummy could understand it?

 

[harleydmn]

Thanks Mike, I will give this a try