Re: value of ph meter

Not sure what you mean by "indirect." If you mean "inverse," it ain't. There is little if any relationship between pH and TA.

You can have two musts with the same TA but very different pHs. (I speak from experience.)

vince norris

In general, the more acidic a mixture, the lower the pH; the less acidic the mixture, the higher the pH. Any acid correction will also affect the pH. If the acidity and sugar are in the right range, the pH will (probably) be as well. That is an indirect relationship.

The pH is a measure of the concentration of hydrogen atoms in solution, and is basically a measure of the strength of the acidity. Some acids are stronger than others. For example, sulfuric acid is considerably stronger than tartaric. Thus two musts can have the same TA, but very different pHs.

Absolutely NOT!

There's no way of knowing the correct amount of sulfite to add to a wine to protect it, and still remein below the threshold of detection by taste/smell, without measuring the pH of the juice/wine.

I quit measuring TA many years ago, but Brix and pH measurements are

Tom S

Ken, I hear that too until they have problem with a batch. Then they want the equipment to guide the decisions they want advise on. That's when properly used and maintained equpment comes to the fore.

Probably 80% of my wines would turn out fine if I did nothing and used no equipment. I'll never know, because I'll always measure.

I have had both very high acid musts from northeastern grapes and very low acid musts from california that I just would not have known how much to adjust from taste; I'm just not that dveloped yet.

I had several Pinot Noir's with an initial pH of ~3.85 and TA of ~5.2, go figure. I guess it was mostly malic acid. If I would have used taste alone, as time when on I'm pretty sure I would have lost them, they never behaved as expected. I still did not prefer the end result, but it's not bad, it's just not my best wine.

I guess that's why we call it an art, you have to develop your instincts and do what makes the most sense to you.

I would never advise some one to fly blind if they had properly maintained instruments, but I would never say 'trust the instruments alone' either. That's how we got Three Mile Island as far as I am concerned. Regards, Joe

... Most folks on this board (myself included)

Vincent and Tom,

Am I correct then in understanding that a pH measurement reflects all acids and is the measure required for sulfite calculations, while TA (via NaOH neutralization) measures tartaric acid only and is valuable for taste purposes only?

Me thinks me needs a pH meter.

Any links or recommendations for pH meter brands would be greatly appreciated.

Jim

TA does not measure tartaric. Tartaric is merely used as a standard reference. But yes, you will find a pH meter VERY useful.

Not exactly. TA measurements report the aggregate of _all_ acids in solution as though they were tartaric. The reading from a pH meter reflects available hydrogen ions (actually, the negative logarithm of the hydrogen ion concentration). A pH meter gives you a better idea of practical, _working_ acidity.

Tom S

pH measures the relative strength of (all) the acid(s). TA measures the percentage by volume of (all) the acid(s), expressed in terms of sulphuric acid. You have to multiply by 1.5 to get the TA expressed in terms of tartaric acid.

The pH of the must is important when determining the amount of sulfite to be added. The higher the pH, the more sulfite is required. The lower the pH (i.e. the more acidic the mixture), the less sulfite is required. However, in the absence of a pH meter, one can safely assume that 50ppm is "close enough" to the optimum amount.

The TA affects the taste of the wine. There is some relationship between total acid and pH, but it is not a direct relationship. Thus one can have a high TA and a low pH, or the inverse. But, any increase in TA will result in some lowering of the pH, and any decrease in TA will result in some increase in pH. Thus the two are related. Furthermore, if the TA is within acceptable range, the pH is probably also within acceptable range.

It's certainly a valuable tool to have.

This is exactly the reason I posted the value in the first place. One could sarcasticly state that taste could almost accomplish the same thing or get a titration kit.

Thanks for the participation in this thread.

Dick

This highlights a difference between European and American winemaking terminology. Here in the US, TA is expressed as tartaric. In Europe, sulfuric acid is the reference.

Tom S

I think I answered that already, but I'd shoot for a starting pH of ~3.4 or so. The wine will always try to return to its original numbers, and the pH will rise as ML completes. It may end up at 3.6 or so, but if you do nothing at all, the pH will go throught the roof!

Tom S

Why sarcastically? How do you suppose this was done in years gone by, when there were no scientific methods to follow?

Taste is the ultimate instrument for all winemakers. That is the one standard that any wine that aspires to greatness must satisfy.

Use your meters and burettes, but be sure to _taste_ the juice!

Tom S

Except that that's not always true, and can be REALLY, seriously wrong. I've seen Pinots with TA's near 6.5 (a little high), and pH near 4.2 (WAY too high).

Knowing the TA didn't really tell me much, but knowing the pH told me that the wine wouldn't be long-lived.

Dave

I've noticed a tendancy in recent times on this group to ignore TA and I know that some of the residents here don't bother measuring it. But there's a difference between ignoring it and saying it "doesn't tell you much".

I agree that pH is more important (read: more useful) but TA still plays a significant role in taste (along side pH). A wine with a TA of

Ben

Yep, you got it. 2000 ppm K+, where our other reds are more like

I wasn't working on this win until fairly late in its life. This year, we are indeed going to make acid additions pre-ferment, and monitor pH closely during ferment.

Dave

Not really. My statement was simply in error. I was thinking of some of the titration kits and procedures, which measure acid in terms of sulfuric, and therefore the results must be multiplied by 1.5 to get the TA. [Other kits, such as Carlson, factor in the multiplier by using a larger must sample.]

But there is a difference between Europe and America in the spelling of sulphuric (sulfuric) acid. ;-)

May I ask how you adjust the acidity without also measuring the TA?

If TA is known, it can be increased to the desired percentage by adding a fixed amount of tartaric acid or acid blend (e.g. 1 tsp per gallon per .15% deficit). There are similar formula for reducing the acidity via dilution with 26º Brix syrup.

Is there such a formula based on the pH, or does one have to "guestimate", play around with a test sample until target levels are reached, and then calculate the amount needed for the larger must volume?

The analytical TA measurement will tell you how much acid to add, or how much reduction is necessary. Unless you have an extra-ordinarily educated pallate, the only alternative would be to make a small adjustment, taste it again, make another adjustment (perhaps in the other direction), taste it again, ad inf.

If I know from experience that I prefer this type of wine to be at (e.g.) 0.61% TA, I can measure the TA, compute the precise adjustment to be made, and be done with it. If I do NOT know what I prefer, I can still bring it to an acceptable range initially, and then perform minute adjustments and taste tests until I get it "perfect". Either way, the analytical data is helpful.

Furthermore, the taste test won't help much prior to fermentation, because the sweetness overpowers the acidity. After fermentation, when the sugar has been converted to ethynol, the taste test is very helpful to determine IF an adjustment needs to be made. The analytical data helps determine HOW MUCH the adjustment should be.

In the earlier example, of an acceptable TA and a extremely high pH, it would have been obvious that "something's wrong" when I tasted the fruit, and I wouldn't have bought the grapes! I realize this option is not open to someone who grows their own fruit, or has a contract obligating them to buy a particular crop regardless of quality.

Additionally, if the TA value weren't available, one might assume that the high pH was because of low acidity, and not take steps to lower the K level.

So, I believe both measurements are important, but --- for the homewinemaker --- TA is the more essential.

I may change my mind by the end of this thread, though. :)

Nah. Bench trials. You can move 1/2 g/l in either direction for 2 to 3 g/l easily enough, and taste all of the resulting samples. If I know the TA ahead of time (and if I thought wine was out of balance, I would want to know the TA. My claim is that there's no point in knowing it as a matter of course, because I don't adjust TA as a amtter of course), then that might help me limit my range, but ultimately it's my palate and the samples that tell me what to do. The analytical data in and of itself NEVER tells me what to do.

And I can't imagine having it in mind that any wine or kind of wine should have a particular given TA, and adjusting the wine to that level based just on analytical data. I'm interested in making balanced wines, not wines which conform to a preconceived notion of chemical composition.

Nope, you're right. Prior to fermentation, it's pH alone I worry about. After fermentation, it's palate and pH I worry about.

They're my grapes. And I'm not so very sure that you could taste what would become a high pH (remember, the TA is where it should be). Have you been able to predict pH changes by palate in the past? The pH of the grapes was ~3.6 or so, and with normal Brix (~23) and normal TA (~6), I'm not sure what taste you'd look for to predict that kind of rise in pH.

Egads! I guess I didn't know that there WERE ways of lowering K+ levels, other than ion exchange, which I don't have access to. What are they?

And it may be that you and I agree more than is evident. I think that knowing the TA is useful if and only if something is out of whack: wierd pH, wine-out-of-balance, etc. But for a wine that I'm happy with, with a pH that will allow it the sort of lifetime I want, and that is typical for the varietal, I don't see any need to know TA.

Dave