Confusing pH and TA numbers

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mendozer

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I'm getting ready to oak my two red wines and testing today threw me for a loop

Syrah - pH 4.29 which is too high, TA was 6.2 which is slightly high (before ferm it was 3.87/9.4)
Merlot blend - pH 4.06, TA 6.9 (before ferm it was 3.87/5.8)

Both underwent MLF and malic acid test today shoes no malic acid. Free SO2 was done today and it was my first time doing an AO test I got 3.2ppm one one and nothing on the other. Very odd, I tried my old accuvin kit (emphasis, expired) and got 8 ppm one one, 4?ppm on the other. Target free SO2 on both was 50ppm from the get go.

Traditionally you add acid to lower pH but I'll have a super acidic wine. So i have to add K-meta for sure i know that, but what do I do about the acid and pH?
 

mendozer

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it is also the first year i added yeast nutrients with calculations. In the past i've just added yeast and let it me. I've made good wine so I'm wondering if I'm starting to try too hard and overanalyze things. More nutrients added means more spoilage potential. The wines tasted good and fruity today but are a bit "fizzy" and harsh bc they're unoaked
 

mendozer

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I'm going to buy a new bottle of .2 NaOH tomorrow. Mine's pretty old. Wonder if it's giving me weird TA readings. that doesn't affect the SO2 numbers i'm getting but I need to get more phosphoric acid for that as well

speaking of, I found a blurb online about using Phosphoric acid 30% to lower pH without affecting TA much. Anyone try this? I'm ok with my TA being where it is now, although I could deacidify it a bit, but i care more about the pH
 

Tin_Man

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Free SO2 will continue to bind immediately at that high of pH, rendering it useless for protection. (ie: your Free SO2 is becoming Bound SO2 immediately). pH has to be ideally below 3.85 for Free molecular SO2 to offer protection. That's why you're getting low FSO2 numbers, which are probably correct.

For TA, use NaOH and phenolphthalein. Or use NaOH and titrate to a pH of 8.2
As I'm sure you know, Tartaric acid is the best solution to lower pH, but your TA is already high (Hence, the "Best of Luck" I said earlier)

I do hope you fix it.
I have no idea about using Phosphoric acid to lower pH. Please don't poison anyone. Good luck again.

Tin
 

mendozer

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he mentions (Pambianchi) phosphoric acid as well as calcium sulfate. I knew the pH was higher than I wanted but i hear mixed feedback on messing with must/wine levels early on. Some add things to make it exact and others don't want to mess with nature until fermentations done.
 

Rice_Guy

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* @mendozer ,, over thinking this , , , probably
* the Syrah on post one is believable, the Merlot blend well I would expect the TA to decrease after running malo
* pH is used in many parts of the food industry to drive a reaction as producing free SO2 or to improve kill rates with microbes. ie I set pH in the primary to make a food safe process. TA relates to flavor impact of the beverage, roughly the more TA the more sweet note needed for balance. , , , , ie if your goal is a dry wine you need to reduce TA, , , , if you don’t care about dry you can balance a 15.0 gm per liter TA with sugar
* calcium sulphate is used a lot in beer. Wine is quite buffered (high solids gives more flavor) so it takes a lot of CaSO4 to drive the pH. ,,, phosphoric acid is a strong acid so it is more efficient at driving pH down. Phosphoric is not legal in commercial wines, but OK for seltzer or soda. ,,, The 10% phosphoric at the brewing store is OK for lightly buffered beverages but not efficient with wine, reagent grade/ industrial grade works faster on a buffered food.
* free SO2 follows something called kPa roughly the lower pH the more of the meta converts into free SO2, .ie better. ,,, HOWEVER yeast aren’t happy below pH 2.8 so we have to compromise. If you were designing a soda with low buffering (synthetic flavor) you would put your pH at 2 or 2.5 and the TA at 2gm/ liter since it is microbial safe and has better shelf life.
 

BarrelMonkey

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I'm going to buy a new bottle of .2 NaOH tomorrow. Mine's pretty old. Wonder if it's giving me weird TA readings.

I would definitely recheck TA with fresh NaOH before doing anything drastic; it can react with dissolved CO2 over time and get partially neutralized. Otherwise, you can determine normality of your existing solution if you have a known acid standard on hand (eg 0.1N HCl). Here is a nice summary of both TA titration and standardization.

Also, do you de-gas your samples before TA testing? If not, that too might increase the apparent TA if there is appreciable CO2 in your samples.
 

mendozer

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I do let it sit in the cups for about 20 minutes while i'm gathering supplies.
And as for phosphoric I have 25% since I use that for my reagents testing. I'm about to head out to grab those chemicals now and when i get back I'll retest TA first. if it was accurate then...i have to figure something out for pH before I put oak in it and let it sit for a few months.
 

mendozer

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ok redid it with fresh .2N NaOH and syrah was 5.6, merlot/cab blend was 5.8. Way better than the 6.2/6.9 numbers i got. I also microwaved the sample for a few seconds to heat it up to degas then cool before testing. Got that tip from someone. pH was still 4.3 and 4.05

I oaked yesterday but didn't do anything for sulfite because unless i decide how to lower pH or if i even want to, i don't know what to do

I racked one wine into a 7.5 gal sanke keg with some headspace (have about 7.25 gal wine) and another into a 5 gal corny plus another 1.75 gal corny keg (6.6? gal wine). I can't really do much better as far as headspace goes unless I buy some commercial wine and add it to the kegs, but that will change my wine composition
 

TurkeyHollow

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It may just be the procrastinator in me but wouldn't it be best to correct the pH to a point where the added SO2 would be effective then actually add the correct amount of SO2 in order to protect the wine? Once protected, you have more time to gather more data and attempt some bench testing. To introduce oak (or anything not intended to protect) without being stable may yield unwanted results.
 

Rice_Guy

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This is a food industry point of view. pH is a preservative principal which industry targets to make shelf life/ have a safe food product. To make an industry quality product at room temperature I would get below pH 3.8 (where you started). You are at the edge of beer production rules ie keep it refrigerated, ,,, or sterile filter/ pasteurize. Risk? ,,, mostly cosmetic/ off flavors, at pH 4 or 4.3 with 12% ABV you should not have health issues.
1) Merlot at pH 4,, would plan on drinking within two years, key is do you like the flavor now? ,,,this is close to target and before pH meters no one would think anything about it.
2) Syrah at 4.3,, if you like the flavor plan on using it up in a year, if you want a few years shelf life drop the pH.

By the way, I target under 3.5.
no other ideas about ph? or should i just let it be?
 

mendozer

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I'd like to not have to guzzle it all down in a few years, so i think i will try lowering it. Not sure how just yet
 

Rice_Guy

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You really only have one choice that moves your pH, to add back acids which were removed from the original juice. Some acids as HCl are stronger than food acids. Otherwise sticking to food acids you are going to push the TA up. ,,, The more acid salts you have in the system/ wine, the more buffering which translates into it currently takes more grams of tartaric to push the pH down and that translates into it takes more sweet to balance the TA.

@mendozer Too bad you don’t have a high acid northern hybrid as Marquette or PetitePearl (TA of 0.7 to 1.10%) to blend in to make the numbers fall in place.

Age related changes take a few years, welcome to the decisions country wine makers do.
 
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I'd like to not have to guzzle it all down in a few years, so i think i will try lowering it. Not sure how just yet
Pay attention to taste. Would you rather have a wine that tastes too sharp but has a 10 year lifespan, or a wine you love but have to drink up within 2 years?

I don't focus as much on the numbers, but I agree with @Rice_Guy that your pH needs lowering. Since it's FAR easier to add more than take some out, I suggest you calculate how much acid you need to reduce the pH to 3.5, then add 1/4 that amount. Stir well, let the wine set for a month, then check the pH and taste. Repeat unless you think the wine is getting too sharp.

You may add all the acid you calculated, or you may not -- I learned this the hard way. There are variables in wine that we cannot control, so taking it slow and steady may prevent mistakes that are hard to correct.
 

mendozer

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i reached out to an old contact who i used to buy grapes from and he said while not legal in commercial winemaking, sulfuric acid could be used. i had not read this, only phosphoric. I'm trying to think of ways to add acid that don't affect taste. Adding tartaric, malic, etc will be perceived
 

Rice_Guy

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Any acid used will change the taste, it will be more acidic/ have more ionic buffering (TA).
there is a tool called a deionization column (like a water softener resin tank) that can increase the protons without adding more acidic ions. Think I read about the AWRI testing them in Australia.
? Trying to think of an application for sulfuric acid in the US food supply, ,,, humm I don’t think I have come across food grade sulfuric but I have some food grade sodium acid sulphate, ,,,, humm.
i reached out to an old contact who i used to buy grapes from and he said while not legal in commercial winemaking, sulfuric acid could be used. i had not read this, only phosphoric. I'm trying to think of ways to add acid that don't affect taste. Adding tartaric, malic, etc will be perceived
 

mendozer

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I ended up not doing anything to it. It has a high pH, oh well. It'll have low free SO2. I bottled today. The wine tasted damned good, so maybe it will go fast in two years. Some of the corks I bought (duo Disc) were exceptionally hard to get into the bottle. None of them made it flush. It's all they LHBS had. Now i know not to use those in the future, other than 88 i have left.
 

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