Help understanding TA

[geek]

Help understanding TA reading with PH meter

@ibglowin Help me understand this and make sure my notes are correct or not.

I have a PH55.
I have 0.2N solution.

Without using water, my notes tell me that I need to use 15ml of must juice.
Then start adding 0.2N solution slowly until it reaches a PH=8.2

So today, I added about 1 gallon of acidulated water to my 29.5 brix grapes on site. The brix came down to 26.
I couldn't check TA on site.

Came home and did a calculation to add another ~1.5L of acidulated water and stirred well.

Then checked TA with the method mentioned above.

I added a total of ~8ml of 0.2N solution and the PH read 7.3
Knowing I need to get it to 8.2, I'd need a few drops more.
Does this indicate the TA is above 0.8 and around .85 or so??


PH is in the 3.7x right now, and SG a bit higher than 1.100 (my refractometer broke, so need to rely on SG and the thick must juice.... )

Let me know if my notes and calculations are correct or not.
Also, would you leave it alone or add a bit of plain spring water to dilute the TA a bit?

Thanks for a quick response...pitching yeast later tonight....

 

[ceeaton]

Varis,

It moves fast once you hit 7.0 or so. I did the same thing last weekend. I ended up with 10 ml of normal solution (mine is 0.2 N also and I use a 15 ml sample).

What I found out is that my normal solution wasn't normal anymore. I bought a new batch and it used 8.2ml to get to a pH of 8.2. My solution was bought this Spring for my Chilean juice/grapes. So this stuff must loose it's potency really fast. So you might want to go purchase some new solution before you panic too much.

I've gotta find a source of the powder so I can make up small batches myself. Also need a scale that can go to .01 grams.

 

[geek]

Thanks Craig, what PH and TA did you end up with?

 

[geek]

I come to realize my 0.2N solution is old, most likely from last year....

Soooo, I am going to rely on PH right now, which is reading in the 3.7x

 

[ibglowin]

You should be able to find some NaOH at a LHBS I would think. It does go bad if you leave it out long enough at room temp. Always store it in the fridge. Morewine has 100ml bottles of 0.1, 0.01, 0.2N NaOH and they are accurate and cheap. You should know by now to stock up on things beforehand instead of scrambling around at the last minute trying to source stuff! Without a refractometer you will be stuck with SG which can be a PITA.

 

[ceeaton]

You should be able to find some NaOH at a LHBS I would think. It does go bad if you leave it out long enough at room temp. Always store it in the fridge. Morewine has 100ml bottles of 0.1, 0.01, 0.2N NaOH and they are accurate and cheap. You should know by now to stock up on things beforehand instead of scrambling around at the last minute trying to source stuff! Without a refractometer you will be stuck with SG which can be a PITA.

Mike, thanks for that info. I was leaving it out in my basement which runs 65-70*F in the summer. Didn't realize I should put it in the fridge. Going upstairs right now to put the new bottle in the fridge and get another Moosehead.

Edit: solution in fridge, Moosehead at my side. Life is good.

 

[ceeaton]

Thanks Craig, what PH and TA did you end up with?

pH of 3.67 and a TA of .82% (8.2 g/L). Planning on a secondary MLF. Just waiting for my Chardonnel juice to see if I can split the bacteria and use it on that batch.

 

[geek]

Yeah, I really thought I had purchased 0.2N solution after the chilean harvest but then realized I was wrong.
I was also leaving mine in the basement.

Anyhow, I ended up adding acid blend to bring the PH a bit, It went from 3.8x down to 3.6x and then I let it sit for a couple hours, stirred well again and the PH fluctuated back up to 3.7x

I left it alone, hydrated BM45 with Go-Ferm, let it sit 15 minutes and then just pitched.

 

[ceeaton]

I think that is a good reason to adjust the pH and TA early in the process. Lot's of reactions going on, especially with skins involved. I think you did the right thing and got it in the ballpark where your yeast can do it's thing then fine tune after you are done.

I'm going to try to keep better track of my TA before and after MLF and see what affect that has on the wine. I've seen in some places that it can reduce the overall TA by .3 or .4 %. Don't really know if I trust those numbers, so I'll have to track my results and see what happens. Would love my Dornfelder to go from .82 down to .7 or .65, but then what is the difference in the taste? I think the taste is most important, the numbers just back it up.

 

[ibglowin]

Acid blend........


NOOOOOOOOOOOOOOO!

You just added a mixture of Tartaric and Malic acid. You DO NOT want to add any Malic acid ever. It can't be removed once added.

Only add Tartaric acid.

Anyhow, I ended up adding acid blend to bring the PH a bit,

 

[ceeaton]

Acid blend........


NOOOOOOOOOOOOOOO!

You just added a mixture of Tartaric and Malic acid. You DO NOT want to add any Malic acid ever. It can't be removed once added.

Only add Tartaric acid.

Not that I use the acid blend, but in this case if he does a secondary MLF would that be able to attack some of that malic acid he just added, or is it in a chemical form that can't be attacked by that bacterium?

 

[sour_grapes]

or is it in a chemical form that can't be attacked by that bacterium?

The pedant in me just loves it when someone correctly uses the singular, bacterium!

 

[ibglowin]

The manmade Malic acid in acid blend can not be metabolized by MLB.....

 

[ceeaton]

A lot of science influenced my formative years. Also where I learned the enjoyment of different delivery vehicles for alcohol. Yum.

 

[ceeaton]

The manmade Malic acid in acid blend can not be metabolized by MLB.....

Thanks Mike. You've now "learned" me on two things today. Thanks for sharing! I really do appreciate it (I know I can be sarcastic sometimes).

 

[geek]

Acid blend........


NOOOOOOOOOOOOOOO!

You just added a mixture of Tartaric and Malic acid. You DO NOT want to add any Malic acid ever. It can't be removed once added.

Only add Tartaric acid.

It was getting late at night and appears I had a "brain fart"

Not sure why I grabbed that bag versus the just recently purchased tartaric container..

Oh well, it wasn't that much and hope the MLF would help anyway.

 

[Reluctant Chemist]

From your calculations, your TA is a little less that 0.8 g/100mL. That doesn't sound bad. Here's my calculation:
Titratable Acidity (g tartaric acid/100 mL sample) =

(mL base) (M base) (0.075) (1,000)
(10)(mL wine sample)
If you want to check the TA on site without need for a titration you can use the Accuvin TA test kit.

 

[ColemanM]

From your calculations, your TA is a little less that 0.8 g/100mL. That doesn't sound bad. Here's my calculation:
Titratable Acidity (g tartaric acid/100 mL sample) =

(mL base) (M base) (0.075) (1,000)
(10)(mL wine sample)
If you want to check the TA on site without need for a titration you can use the Accuvin TA test kit.

And this is exactly why kit wines sell so well. Man o man, I get so lost in these equations. I wish I understood this better, I feel my frozen must wine would probably turn out $100 bottles of wine.

 

[geek]

Re-checked numbers after alcoholic fermentation.

PH=3.8x
TA=.8x

For the TA, used new 0.2N agent, 15ml of wine and around 8ml of 0.2N with a few drops to get ph meter to mark 8.2