Use caution when testing TA with ph meter
- Thread starter REDBOATNY
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One thing I have been wondering is if its better to add acid before or after fermentation? maybe both? The fermentation produces CO2, which would combine with water to make carbonic acid (thank you to the person who reminded me of this). I know its not a strong acid, but would it dissociate enough to throw off the acid content in the final product? Or would applying a vacuum to degas afterward fix that? (Im probably over thinking this)
Yes, the CO2 makes it more acidic, but we generally take that out of reds by degassing. Most winemakers leave a little residual CO2 in whites for a smidge more acid.
I personally think its better to add acid up front (at least with reds for sure) whites are a little less complex and seem to incorporate acid just fine even post fermentation. Post fermentation is nice as you know exactly what you have, not much guesswork like when you add pre-fermentation
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Ajmassa
just a guy
This "acid adjusting up front" question is just personal preference and neither is 'better' with all depending on a lot of different variables right? Especially with equipment and work space as factors.
Personally the 1st thought that comes to my mind is when adjusting before primary all the extra time needed. And adding and waiting and checking and adding...etc. I'm hesitant to let fresh pails go unrefrigerated for too long while adjusting. Pickup day is Yeast day for me.
If you had to adjust the acid and wait and check, and if by chance you needed to add again and then wait and check, how long would that take? Shouldn't you be letting the acid additions sit for a day to get a proper reading?
And related question, how long can you leave juice sitting w/o pitching yeast before problems could arise? (I don't sulfite until maybe a week or so after racking to carboy or demis)
Personally the 1st thought that comes to my mind is when adjusting before primary all the extra time needed. And adding and waiting and checking and adding...etc. I'm hesitant to let fresh pails go unrefrigerated for too long while adjusting. Pickup day is Yeast day for me.
If you had to adjust the acid and wait and check, and if by chance you needed to add again and then wait and check, how long would that take? Shouldn't you be letting the acid additions sit for a day to get a proper reading?
And related question, how long can you leave juice sitting w/o pitching yeast before problems could arise? (I don't sulfite until maybe a week or so after racking to carboy or demis)
With my Vinmetrica setup, using 5 ml wine, 15ml DI water, and .133 solution, the result is obtained by multiplying the amount (in ml) of solution used to reach pH 8.2 by 2. So if you use 3 ml in your titration to reach 8.2, the TA is 2 *3, giving 6.0 g/l, or .6%, whichever way you prefer to look at it........
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This is the generic formula for using any sample size and any strength NaOH
TA as tartaric acid in (g/100 ml (or %)) = (V)(N)(75)(100)/(1000)(v)
V = ml of sodium hydroxide solution used for titration
N = Normality of sodium hydroxide solution
v = sample volume (ml)
TA as tartaric acid in (g/100 ml (or %)) = (V)(N)(75)(100)/(1000)(v)
V = ml of sodium hydroxide solution used for titration
N = Normality of sodium hydroxide solution
v = sample volume (ml)
Like they I say, I could tell you but then........
Lets just say I don't necessarily make the boom. But I do make the boom better!
Lets just say I don't necessarily make the boom. But I do make the boom better!
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Like they I say, I could tell you but then........
Lets just say I don't necessarily make the boom. But I do make the boom better!
Knows about you, Mike. I spent my time in the Air Force during the Cold War analyzing the other guys' junk to figure out how bad his boom was.
Is it correct to multiply the amount of NaOH used to titrate the sample by the size of the wind sample? For example with a 5 mL sample you multiply the amount by 1.5. (that's with the instructions in my kit) I saw in this thread that someone said with 15 mL you can multiply by one. Just trying to understand the reasoning for that.
Look at the formula Mike posted a few back. If you know some of the variables, they can be inserted into the equation and simplified. For instance, this is the Vinmetrica solution:
Calculate the TA value as:
TA (g/L tartaric) = (V *.133 * .75) / S
where
V = mL Titrant needed to reach the endpoint;
N = normality of the Titrant,
S = mL sample.
If you use 5 mL of sample as directed, and the Titrant is 0.133 N as supplied, then the calculation is simply:
TA = 2 * V (i.e. 2 times V)
So if you use the.133 solution and 5 ml sample as I do, the equation above is applicable, and simple. You can insert your normality and sample size, solve the equation and come up with a factor based upon your parameters.
The reasoning is that the other parts the equation then just cancel each other out.
And yes there is a formula in which you don't have to dilute your wine and it may use 15 ml sample size but it may use 0.2 N NaOH. Since I don't use that I don't have it off the top of my head. I don't wish to use 15ml at a time of my wine each time.
And yes there is a formula in which you don't have to dilute your wine and it may use 15 ml sample size but it may use 0.2 N NaOH. Since I don't use that I don't have it off the top of my head. I don't wish to use 15ml at a time of my wine each time.
Ajmassa
just a guy
Yes and yes. The Vintners Best kit I used calls for a 15 ml sample (hated pulling larger samples) and does in fact use .2 NaOH. So if it takes 6 ml of solution, then your TA is .6. Easy peasy
