TA and pH

Absolutely right? You disputed this when I said it. You are truely French. How pathetic. You are only fooling fools at this point Ian.

Amen. Unfortunately, one doesn't have to reply to him to get insulted. All one has to do is post an innocent question. See the thread that I started on pH vs. TA.

I use Free Agent as a newsreader. It does not have killfile capability. I understand that there is an advanced version available at a nominal cost which does have this capability. I'm going to pay to get it just to get rid of this idiot.

And please, to others, don't include quotes from this imbecile in replying to any post, even if he was not the originator of the post.

Vino To reply, add "x" between letters and numbers of e-mail address.

I haven't kill- filed you as of today but having just read this drivel- goodbye you sick puppy!

Larry Southern Ontario

>

Salut/Hi Vincent Vega,

with apologies to Mike.

le/on Sun, 18 Apr 2004 17:23:17 GMT, tu disais/you said:-

Thank you. In this post you have demonstrated just how much of a fool you really are.

French bastard.

Hahahahahahahahahahaha.

1. I never lie here.
2. I'm not French
3. I'm not a bastard, I have a birth certificate to prove it.
4. The sentence makes even less sense than most of the previous 80 or so to which you've subjected us.

Good lord!!! Something about which we agree.

Really? What's that got to do with me? If you don't have the wit to realize that someone with the name "Ian Hoare" who writes English with as much fluency and precision as I do, cannot possibly be French, then you really must be pretty dim!

I don't remember EVER calling myself superior. Except in IQ, and that I can prove easily.

Ah yes. John Wayne won the war single handedly, and the French never fought the Germans at all in the 20th century. I've read the scenario. It's history according to Hollywood, Vincent, and you spout it with the same malevolent ignorance that you have demonstrated throughout the last week or so.

True. However it has enabled me give you enough rope to demonstrate all by yourself, clearly and unequivocally, that you're a stupid, ignorant, prejudiced lout thank you.

I hope that I am the last person who addresses a word to you here on this newsgroup.

Craig, Although the wine is a better buffer because of the acid salts, the difference between TA and pH arises simply from the fact that the acids found in wine are weak enough to not be fully ionized at the pH found in wine. What I mean is that even if a wine had only lactic acid in it, there would still be a non-linear relationship between TA and pH. This has been codified by a simple equation known as the Henderson-Hasselbach equation (a big name for a trivial concept).

Thanks to both you and Tom for your very clear explanations of the meaning of TA.

Mark Lipton

relationship

Of course the level of dissociation of acids is a consideration, which is why I specified approximate linearity only for a certain interval after the buffer capacity is overcome. In wine, with its high potential potassium concentration, the buffer capacity from the salts is the major contributor in the relatively narrow pH range in which we are working. Yes, pH is only indicative of dissociated H+ concentration, not absolute H+ concentration.

Craig Winchell GAN EDEN Wines

I may not be explaining what I mean very well, which is why you're talking Henderson-Hasselbach. I'm talking not about the sodium hydroxide titration, but rather tha amount of acid I must add to decrease the pH to a given extent. So I wish to decrease pH, and I add tartaric acid. I often end up adding enough to precipitate cream of tartar at room temperature, perhaps decreasing the pH slightly, while not increasing TA at all for a while, because the tartrate is precipitating out. You are discussing the sodium hydroxide titration itself, from around pH3 to around pH7, a very broad range, where there's a multi-sigmoidal relationship between pH and amount of sodium hydroxide. I'm discussing the fact that I can have a wine with pH

3.4 or a wine with pH 3.2, and still have the exact same TA, but they will taste different. Or I can approximate the taste of the pH 3.2 wine in the 3.4 wine by raising the TA to a certain level, but I still might end up with a wine which doesn't taste as fresh. Or I can take a wine with pH3.5 and TA of .65 g/100ml as tartaric, add .35 g/100ml of tartaric acid, and end up with a wine of pH 3.15 and TA of .75, because I've precipitated out a bunch of cream of tartar in the process (US law limits the amount of acid added to be no more than what would raise the wine to a level of 0..8g/100ml, calculated as tartaric, so I'm counting on my ability to use up the buffer capacity of that potassium by precipitating the cream of tartar, liberating a hydrogen ion per KHTartaric molecule in the process). Of course, I must do trials, because every wine is different.

Craig Winchell GAN EDEN Wines

Hi Ian,

Don't worry; you're not losing your mind. TA can also stand for Total Acidity. It's more difficult to measure (at least in wine) because the volatile acids have to be measured, I think usually by distillation. Many wine makers feel that titratable acid and pH are good enough measurements because they can be don't quickly and simply in the winery.

Andy

The terms total acidity and titratable acidity have come to mean the same thing. Titratable acidity is the more accurate term, since that is how it is measured, and it implies titration to a particular pH endpoint. These weak acids normally completely titrate out to a true endpoint between pH 7.8 and 8.3, rather than 7.0. We don't worry about VA contribution unless we're up against the .8 g/100ml limit, where such a small difference in values could make the difference between legality and illegality.

Craig Winchell GAN EDEN Wines

That's perfectly clear, Craig. I was simply considering Tom's titration analysis. What you say about adjusting pH makes total sense.

Mark Lipton

"Craig Winchell/GAN EDEN Wines" skrev i melding news:S6Tgc.2377$ snipped-for-privacy@newsread2.news.pas.earthlink.net... Hi, good to have that put down; like Ian I was a bit confused over the right term to use. But, shouldn't that read *titrable* acidity? Anders

Thanks to all (well, maybe not ALL, if you catch my drift) who contributed to this thread. The question I posed was one I had had in the back of my mind for some time and some recent experiences brought it to the fore. I can't claim to fully understand all of the chemistry discussed here, but I certainly learned a lot and hope that others did also. This sort of thing is afw at its finest.

Vino To reply, add "x" between letters and numbers of e-mail address.

That's how we always used it in the good old days in the university chem lab, but these days anything is possible - you can 'grow the economy', and the other day I heard someone on the radio saying they were going to do something because it would 'progress their cause'.

Gag.........

I hate to get into this question so late in the game, but isn't there an equation that explains this? Seems to me there is one and would be understandable to all. Winemakers must know it.

Rich

Concerning the relation between pH and TA, Rich states: "I hate to get into this question so late in the game, but isn't there an equation that explains this? Seems to me there is one and would be understandable to all. Winemakers must know it."

The complication is that wines contain acids that only partially ionize into a H+ ion and a - ion that contanins the rest of the acid. pH is approximately a function of of the H+ ion concentration. How much the acid ionizes depends on the acid, the solution it is in, and the concentration of the acid. This is complicated in wine because you can have more than one acid in a solution of water, alcohol, and sometimes sugars that can vary in composition greatly. There are equations to handle this sort of mixed system, but you would in general have to have an analysis of the wine for the quantity of each type of acid, alcohol, water, and sugar. Then studies over a wde range of composition would allow the parameters needed in the equations to be found. Such a rather complete chemical analysis of the wine is quite possible, but not something that the average winery would be set up to do or willing to pay for on outside contract. It is quite possible that someone doing wine research in one of the universities has looked into this. It is also possible, that for the range of things found in wine, it could be shown that use of TA and a few simple corrections would be enough. However, someone would have had to study the details before you could be certain how accurate you are. If you had only one acid in a solvent of fixed composition, this is a classic experiment that one might do in a physical chemistry lab course.