The problem here is, due to buffering capacities, your TA will not always track the inverse way with pH
But to answer the question, it’s the TA that will affect the ‘tartness’ of the wine, so if two wines have the same pH and one has a noticeably higher TA, that will will taste more ‘tart’, assuming those are the only two things at play here.
Cheers
This is what we do with the rare Panama White Sauvignon Blanc bottling. It’s risky but the results have been crazy delicious and gobsmacking. Would not want to attempt this with more than the 1/4 ton or so of fruit with which we have done it.
I’m going to ask my question a different way, but perhaps it will simply yield the same answers.
Let’s say we have a Pinot Noir that comes-in at 3.22 pH; 7.5 g/l TA. We’ll call this the “Baseline Wine.” It tastes, smells, and feels the way it does.
How will the taste, smell, and mouthfeel differ from that of the Baseline Wine if that “same” wine instead comes-in at each of the following?
I assume all these permutations reflect different grapes at harvest, which leads-to the differences in numbers. I’m just trying to isolate the sensory impacts of pH being lower or higher from the sensory impacts of TA being less or more. I tried to choose upward and downward movement significant enough - of both the pH and TA - to yield an answer other than, “That’s such a small change it won’t make a perceptible difference.”, but if I failed in that endeavour please feel free to use more drastic upward and downward movements. … And perhaps my question is impossibly flawed in some way – I don’t know.
Happy to receive responses from anyone in a position to answer. 
It looks like @larry_schaffer answered one or two of these permutations in his post a couple before this one. But I’m still interested in hearing more.
I think what Marcus is saying is that (holding TA constant) the pH can vary a lot based on the mix of acids (tartaric, malic, lactic, citric, etc.) And the way we perceive pH mostly comes from our perceptions of those acids, not necessarily the scalar value of the pH.
You might think “what’s the difference, acid is acid”, but it is fairly important for how we taste wine. I think there is a book by an MW called “Beyond Flavour” that talks about trying to distinguish between the acidity profile of a wine and use that in blind tasting to help identify the wine (I’m paraphrasing here, it’s been a while since I read it).
Yeah I think Chris nailed it here. When you start to get into the fine details of things like this and relate them back to flavor, it kind of falls apart. Flavor and acid perception is such an individual thing. When you factor in the rest of the wine and all its flavors its hard to make a definitive rule on what those differences in acidity would taste like.
The way in which you perceive acid is modulated enormously by the aromatic compounds that come along with the acid. These are what determine in large part whether a wine tastes “juicy” or “sour” or “razor-sharp” or”lip-smacking” or however you want to describe acids, even at the same pH and TA. The very differences in ripening and soil/grapevine chemistry that lead to variations in pH vs TA also modify the aroma chemistry of the grapes and wines produced. So, unfortunately, it is impossible to separate them.
For example, high TA at a given pH can be a result of high malic acid relative to tartaric acid. But the physiological processes in the grapevine that control acid degradation during ripening are impacted by the same environmental factors as the processes that control the development of aroma compounds. A wine can taste “green” in its acidity (or tannin) in part because of high malic acid, but also due to high levels of undegraded aroma compounds associated with low ripeness (e.g. pyrazines)
I only work off pH myself and largely ignore TA, and I have a few golden, but very basic and simple rules that I try to abide by around harvest. One of them is, almost all red wines taste great at 3.6pH, so my window is around there, 3.5-3.7. That’s much more important than sugar level. However, pH isn’t always available in the field, so here you have to go a bit by proxy and interpolate. If you’ve worked with a vineyard for many years, you kind of know where they are roughly.
If I’m doing whole cluster, I know it will add 0.1-0.2pH to the end product as a general rule. Whole cluster dresses itself up and can appear sensorily as acid, so one might not have to compensate for that by picking earlier, but it certainly is a factor when I’m deciding on later harvest fruit where the pH is already getting high. And it does matter when it comes to SO2 and volatility.
If you look at a chart of how much free SO2 you need to protect the wine for each pH, you can see that it literally hockey-sticks after 3.6pH. A Riesling at 3.0pH needs almost no SO2, but a cab at 4.0 needs a ton. SO2 changes the wine, even after bound up and integrated, so it’s another reason to be conservative on the pH side.
Very cool. Björnson makes an amazing later harvest Sauv Blanc bursting with flavor; and as I recall it’s 14.5% ABV. I was shocked to see that because the acidity and flavor profile had absolutely no hint of high alcohol on the palate.
This thread has taken an interesting foray into juice and wine lab analysis, but I think it’s important for folks to know that most of us pick for flavor and other ripening indicators and treat labs as secondary information, right ? (at least all the craft wine makers I know— probably not the case for large scale producers I would guess)
BTW, last few years I’ve done almost no lab work at all - and it’s been really liberating. Take the sugar reading, might do a little pH reading at crush and that’s it until it’s time to bottle and I get a wine panel done. Used to be so tied up in all that lab stuff in the beginning, so it’s nice to be free from the shackles of it. Certainly I don’t miss the $120/pop sample costs either - it really added up sometimes.
Only time you need it is when stuff kind of goes wrong, high VA or you get stuck ferms, then it’s useful to get some more info.
I am not a winemaker or a chemist, but the message I’m getting from them is: “It’s not that simple.”
Look at this way: two wines might have the same pH and TA yet their acid profiles may be perceived differently when tasting them because they arrive at those numbers with different relative mixes of acids (malic, lactic, citric, tartaric, etc.).
Fascinating stuff.
Once again, the generosity of winemakers who post about their craft here is simply fantastic. 
Not so fast, Mr. Roadrunner! 
You’re getting ahead of me — gotta take it one step at a time. (that said, I understand where you’re coming from, at least insofar as I understand there is a difference in experience between malic and lactic acid in wine).
Thanks, Ben. I feared the answer would be something along these lines. I say “feared” because the fact that this is the case makes it much more difficult, if not impossible, to understand how variations in pH, alone, and/or variations in TA, alone, impact the wine drinking experience.
My disappointment aside, I do understand what you’re saying, and I’m appreciative of you taking the time to explain. 
Yeah, I was kinda expecting “It’s not that simple.” as an answer, but was hoping otherwise. It is what it is!
Why isn’t this upvoted more? It is an “always choose the lesser of two weevils” level pun.
I don’t know how answerable your questions are, but here’s something that has helped me. You can find Sherries and Madeiras with similar levels of pH and residual sugar but significantly different levels of TA (higher in the Madeira). It takes some digging through tech sheets, and sometimes understanding that TA might be expressed in different ways (tartaric vs. sulfuric), but I think it’s extremely valuable.
To me, pH impacts the up-front sensation of acidity. Very low pH means the instant “bite” when the wine gets into my mouth is pronounced. Higher pH makes the initial sensation softer. TA impacts how long-lasting the mouthwatering is. High TA makes my mouth water for a long time, while lower TA means salivation stops sooner. You can look at numbers for outliers like Hunter Valley Semillon to try to get a handle on this as well. Comparing different vintages of Champagne can also be helpful (not usually as acidic as you might think).
I read the book and saw a seminar he gave on it. It can be helpful to some people, but it isn’t as technical as people might think, and there’s some information in there that’s simply wrong (such as Riesling always has high acidity – I found several examples like this). He talks a lot about the “shape” of acid and tannin, which is very abstract, and really based on personal experience rather than technical sensory analysis. I do think there’s some valuable information in there, but that it all should be approached with a bit of skepticism. He seems to have found an approach that works extremely well for him, but that might not work for a lot of other people.
Taste is personal, so no approach is going to be anywhere close to covering the field so to speak. And that’s just in wine geek circles. Imagine trying to express this stuff to people who enjoy but don’t obsess about wine. Heck, imagine trying to express it outside the English speaking world. A model that works for one person might resonate with other people or not. That makes no judgment on the model.
Some many years ago, I was told by a couple of different winemakers that they pay more attention to TA than pH in white wines, while the opposite was true for them with red wine. I don’t know if that makes sense to any of you…or not. But it was an interesting observation that different numbers and different wines react differently.
Adam Lee
Clarice Wine Company
The clear and obvious answer is Domaine de la Cote. Tons of tension and finesse.