We are using pH 4662 test strips to find the acid in our fruit wines. We got the test strips from a wine making shop, The salesman said they were for acid but they say pH is this what we are supposed to have or is there a conversion to find the correct acid levels? Name: Gene P. State: PA ----- Hello Gene, I would like to thank you for such a great question. Wine acidity and pH is a subject that confuses many home winemakers. And to make matters worse, it becomes even more head-spinning when you start throwing in terms like titration or titratable acidity. Let me see if I can break this down into language that is easier to understand. First Of All, What Is Acid? In the context of wine making, it is the stuff that makes your wine more tart or sharp tasting. Not enough of it, and your wine will be flat, lifeless, and in extreme cases, insipid. It's also the stuff that helps your wine to be more stable. This means: less likely to be overcome by mold, bacteria, or oxidation. It even contributes to how brilliant your wine's color will be. To sum it up, acid is an integral part of any wine. pH Readings vs. Titratable Acids Gene, to speak to your suspicions directly, there are two ways by which you can measure acidity in a wine: by pH and by titration. pH READINGS: A pH reading will be numbers like 3.9 or 4.4. There are two things to know about these numbers. First, they run backwards. That is to say that 3.0 is higher in acid then a 4.0. Secondly, the scale is not an even one. It is logarithmic by a factor of -10, which is a fancy way of saying that a wine that has a pH of 3.0 has 10 times as much acid as a wine with a pH reading of 4.0. Remember it goes backwards. For most wines you are looking for a pH reading of 3.4 to 4.0, with the sweet-spot being around 3.6. A pH reading can be taken with pH strip, such as the ones you have purchased, or with a digital pH meter. In either case the readings are almost instant. Just put a drop of wine on the end of a pH strip and allow it to dry. You then match the color change of the pH strip to a color chart to determine the wine's pH. With the digital pH meter it's just a matter of putting the meter's probe directly into the wine and wait for a reading. Not much harder than taking a temperature. TITRATION READINGS: A titration reading is a little more straight forward. It gives you a reading as a percentage of the wine. Optimal readings can very from one style of wine to the next, but essentially you want to be somewhere around. .55% and .75%. Titratable acidity is measured with an acid test kit (titration kit). In simple terms, when using an acid test kit you are adding a solution to a wine sample until it changes color. You get your acid percentage reading by measuring how much of the solution it took to change the wine's color. The Different Between pH And Titratable Acidity In Wine While both methods measure acid, each are measuring it in a very different way, so much so, that one scale can not be converted or correlated to the other. This is where much of the confusion lies between pH and titratable acidity. As an example, if you have a pH reading of 3.6, it can not be correlated to any corresponding titration reading and vice versa. To carry this further, you can even have two wines with the same exact pH reading but with different titration readings. That's how loosely correlated they are. CONFUSED YET? I'll try to explain the difference as simply and plainly as possible. That's my promise. But in order to do that I may take one or two technical liberties as a way to keep things simple. I only say this because I know there will be some people out there that will want to correct me on some of these explanations. NOT ALL ACIDS ARE THE SAME There are many different kinds of acids that can be found naturally in a wine. Each are made up just a little differently. The common ones are: tartaric, citric, malic, lactic, ascorbic and succinic, along with many others in smaller amounts. The important thing to understand is that each one of these acids has a different strength of tartness on the tongue. Some acids are very sharp, while others, not so much at all. As an example, you can take two one gallon jugs of wine that are identical and add to one of them a 1/4 ounce of ascorbic acid and to the other, 1/4 ounce of malic acid and get two completely different levels of tartness in each case. While the amount of acid added to each gallon was the same, the resulting level of tartness was different. This is because different acids have different strengths. TO THE HEART OF THE MATTER Now that you understand that not all acids are the same, I can explain to you the difference between pH and titratable acid.