PH vs Titration ?

[Tall Grass]

I haven't done any acidity testing yet but after a few 1 gallon 'experimental' batches I'm considering getting an acid testing kit but it seems like the PH strips would be the easier way of doing it. Most of the local brew shops carry the titration kits which are relatively cheap.

Now I'm reading Jack Keller's website about acidity testing that has me scratching my head,

http://winemaking.jackkeller.net/acid.asp

Although TA and pH are interrelated, they are not the same thing. A solution containing a specific quantity of a relatively weaker acid such as malic will have a different (higher) pH than a solution containing the same quantity of a stronger acid such as tartaric. So, another way of thinking of pH is to say that the acid in a solution with a pH of 4 is 10 times stronger than the acid in a solution with a pH of 5.

The pH of a solution is defined as the negative logarithm of the hydrogen ion concentration in gram-atoms per liter. Hydrogen ions (H+) are formed when a dissolved acid partially separates (dissociates) into hydrogen ions and and related anions (A-). The concentration of hydrogen ions largely determines the effects acids have on wine. A stronger acid such as tartaric dissociates more than a weaker acid such as lactic. Thus, the effective acidity of a solution depends on the concentration of all acids in the solution as well as their tendency to dissociate hydrogen ions. Effective acidity is measured as pH.

The measurable range of interest in acidity is a pH of approximately 2.5 to 4.5 for must and wine and a TA of 0.50-0.85%. We have already seen how to measure TA. Now we will look at measuring pH.

I'm not really sure what to make of that.. does anybody here use ph strips with much success?

 

[Madriver Wines]

I use them as a general guidline. They are not very accurate since the scale I have goes 2-4-6-8 so finding 3.4 is kinda tough. What I can see is weather or not I have added the acid and if it was too much or not enough. Hope this helps, Steve

 

[Malkore]

I don't think they are exactly the same. I think acid titration tells you the available acid in the must. pH tells you over all the acidy, alkalinity or neutrality of a solution.

Something could have enough acid, but show a neutral pH if there are other buffers present.

Titration is gonna serve you better. plus pH strips can be easily skewed by temperature and humidity can ruin them completely.

 

[Luc]

This is for most winemakers a difficult subject.

Try to see it as this:
You can imagine that there are several substances that weigh the same but have a different strength. Just like some fruit have more flavor as others have. So if you add a pound of the one kind of fruit it would add less flavor as when adding a pound of another kind of fruit.

Now an acid testing kit measures the weight and a PH testing kit or strips measure the strength.

This is a bit of a shortcut but about covers it in simple terms.

Once we made a wine with a complete group and the wine was too acid. This was because we had to add a certain amount of acid to the wine but we used citric acid in stead of tartaric acid.
http://wijnmaker.blogspot.com/2008/03/waarom-is-mijn-wijn-zo-zuur-why-is-my.html

This is a bit how PH works.

How an acid measurement kit works is described here:
http://wijnmaker.blogspot.com/2008/11/zuurmeting-01-measuring-acidity-01.html

Luc

 

[Tall Grass]

Thanks for the replies! This is something I might have to order over the internet because I want a titration kit with a test tube. I've been to 7 wine shops in this city and they all sell the same kit with a flimsy plastic cup for $12

It's not really surprising though.. there is only ONE yeast available in this city, Lalvin EC-1118.. that's the only one anybody sells around here. One lady working at a kit shop even admitted to me that she didn't know there were other yeasts available

I'd prefer to support the local shops but they're not well suited for my needs.