Why the need for TA numbers?

[rkreev...@gmail.com]

I am regularly perplexed by people's deep desire to know TA numbers. I keep a wet chemistry lab of sorts in my home, hot plate-stirrer, burets, flasks, scales, buffers, reagents, etc, (some of) you know the routine, but I haven't kept the reagents for determining acidity around for a decade or more. The reason isn't that I'm cheap, I'm not, it's that the TA number doesn't help me understand what the needs of the juice, then cider, are, i.e. what interventions are going to be prudent.

I get that 3 g/l is probably insufficient and 9 g/l is probably excessive but knowing whether the juice is 4.8 g/l or 6.2 g/l is information that I cannot see the value in. pH is the number I want and need, pH is the reason I keep a quality pH meter in my toolkit, replace buffers and the rather expensive probe if the slope is out of spec or can't recognize the buffers relatively quickly. I never deacidify, I've almost never seen a juice below 3.8 pH, so for me it's check pH, add acid, check pH again, repeat as necessary. But if I did have to deacidify the pH meter would still be the proper tool for me.

After the cider is dry I can taste the acid level for palatability. I don't have much of a palette trust me, but I can certainly discern the difference between flabby and tart as, I presume, can you.

In my situation I'm generally trying to balance between what is a relatively acidic, to my palate, dry finished cider as I find that pairs well with what's for dinner, with a pH that doesn't require 350 ppm total sulphite to obtain a 0.6 molecular ppm at bottling. Would it be unfortunate to end up with a dry cider that had 8.2 g/l acid with a pH of 4.1? Sure, but it never happens. I consistently achieve palatability, granted of unknown finished acidity, with pH's in the 3.7-3.8 range.

I understand that everyone's situation is different: I start with high pH base juice, and I desire a dry, ml complete, still cider. Not everyone has what I have or wants what I want in a finished product.

All of the above is just long-winded way to get to my question: can you help me understand how knowing the TA# helps you make a better cider? I am genuinely curious: what are the situations/circumstances that make the knowing of TA useful/important/critical for you as a cider maker ?

[Miguel Pereda]

In my case the range 2.5 - 4.5 g sulphuric/L of TA is the optimum. Below that, there is a risk of vinegrowth and above that, it is very difficult to complete MLF. For ciders that must ferment to dryness and complete MLF before bottling. With wild yeasts and bacteria and without the addition of sulphites or any other additives. That's why knowing this value is important because that's how I know if the blend of apples used is the right one. 

And sensorially, a 2.5 TA cider is not going to be the same as a 4 g sulphur/L cider.

Miguel A. Pereda

[woodcarver]

In reply to the original post, I will list one reason why TA can be useful. I grow some varieties--and collect some wild fruit--with very high sugar levels and high acid levels. The high sugar levels can obscure my capacity to sense the real level of acidity. In that situation it's not trivial to guess how much low TA juice I would need to add to bring down TA to a reasonable level. Now, yes, I could wait until I the cider went dry and then the level of acid would be completely apparent and I could blend in lower TA cider (if I had happened to have some). However, the issue here is that 1) sometimes there are sensorial benefits to blending before fermentation 2) by blending in my low pH juice prior to fermentation I will have achieved the TA balance I want without having to acidify the low pH juice (which could preclude me from using it to lower TA in a post fermentation blend) and/or without having to add a ton of SO2 to the low pH juice to protect it during fermentation. It seems that in your situation that perhaps knowing TA might be less critical but I've never been in the situation where I've just had too much low pH juice--I usually have the opposite problem. It sounds like you're getting results you like without the bother of testing TA. More power to you.

[Bob Hall]

Another reason that TA may relate to more of what you taste as sour than pH.  The pK of malic acid is 3.4 meaning at pH 3.4 half of the H+ are dissociated and there is a strong buffer.  So for a given pH  high TA will buffer pH increases when tasting and be perceived as more sour.  From a practical standpoint TA is measured on an arithmetic scale and pH on a log scale.  A 50% decrease of TA from 6 to 3 would is trivially easy to measure, but a 50% decrease in H+ is only 0.3 pH units higher.

Bob Hall

[Claude Jolicoeur]

Why I prefer to work with TA:

- Easier to predict the resulting acidity after blending. If I blend half and half juices that have TAs of 2.0 and 10.0, I know the result will be TA 6.0. You can't do that with pH. For less obvious blends, the Blending Wizard spreadsheet works great.

- TA relates to taste perception while pH is more for biochemical activity.

- I find it is easier to maintain good calibration with TA - I have in the past had innacurate buffer solutions and other problems with pH meters.

- I aim for my blends at TAs between 4.5 and 6 g/L as malic acid. The resulting pH is always pretty close to 3.6.

[Johan Strömberg]

In addition of blending that Claude mentioned earlier TA is very useful value for me when I do secondary bottle ferment for sparkling cider. Even two grams of TA has significant result of how (young) carbonated cider will taste.  It's very possible that you won't taste say 6g of TA too sharp in still cider when it can be too much on carbonated. That's something that pH won't really tell.

-Johan

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[luis.ga...@gmail.com]

I would also add that tannin content in an apple can make the TA perception hard to guess. 

Maybe for someone that make cider with only the same couple of apples varieties every year could guess only by taste what is the good blend for a good cider. I work with too many apples to do this and have preductable results....

Also, TA test take only a couple of minute per sample and don't require complicated to deal with reagent or fancy equipment. Why not do it?

Actually, I beleive that  TA is a more critical information than pH if you don't sulfite (or at least, not at full dose). Like Claude said, in a balanced blend, you usually end up with a pH around 3,6, which is safe. 

Louis

[Miguel Pereda]

The final pH of a balanced blend depends on the apples and the style of the cider itself and can range for example from 3.4 to 3.8. It all depends. What is quite likely. That above 4 can cause problems in ciders without sulphites

Miguel A. Pereda