Re: Acid titration kit

Try this link for a better explanation

I have a kit which I haven't used for years, it's much simpler to use and seems accurate enough. It consists of an eye dropper, phenalalanine, as u stated and sodium hydroxide to titrate with. A measure is found just by counting the number of drops from the eye dropper. So easy :-) eh? I have lost the instruction pamphlet that came with it, doh! Or I would of scanned it for you.

I ran out of Sodium Hydroxide so I asked my local chest to make up a bottle for me. A standard solution which I believe is N/10 cost literally coppers (I'm in the UK LOL) certainly no more than a UK £ and he made me 500ml, that has lasted years.

You should be able to buy the phenalalanine at a good winemaking stockist and an eyedropper at the chemist. I think u may need a measure in c.c. if I remember correctly.

Will get back to u if I find any more info.

As long as we are on the subject, how does one obtain a TA reading of a red wine? I've added solution to the sample until the sample turns color (blue), then added the indicator. I then start titrating. I can never see when it turns pink. I must be going color-blind. Can someone expound on this procedure?

--Lee

Thanks! These directions diverge somewhat from those with the Presque Isle kit, which suggests adding some hydroxide to the sample until the color changes, before adding the indicator. Hence my confusion.

--Lee

As Ken just said, you can buy a kit for $5-10 at your local homebrew store or (if there isn't one locally)

The kit will contain: a graduated 20-ml syringe, a 25-ml test tube for the sample and titration, a bottle of phenolthalen colour indicator, and a bottle of 1/5 normal sodium hydroxide reagent. There are also instructions for its usage, with target percentages for various wines, and instructions for adjusting the acid.

The only thing NOT included in the kit is the acid, which you can purchase at the same time. For grape wines, use tartaric acid, or acid blend. For country wines, acid blend is probably better. For purists, get tartartic, malic, and citric acids, and create your own percentages depending upon application.

You can also use a pH meter with at least +/1 .1 accuracy. although .05 is preferable. In that case, you would take a sample, stick in the probes, and add acid to the sample until you reached the desired pH (3.2-3.4 for red wines), then add the same proportional (acid/volume) amount to the main must.

You can get a decent pH meter for about $70 from either of the two places just mentioned.

It can be very difficult to detect the end point with red wines. However, you can (and should) dilute the sample with distilled water. Then it is much easier.

With MOST kits, the dilution does not affect the test results. With some of them you have to factor in the amount of water.

If you have the sort of kit in which you take a fixed amount of must, add 3-4 drops of color indicator, and then add hydroxide from a graduated syringe until you reach the end-point, you can safely add

There is another sort of kit where the graduations are on the test cylinder, not the syringe. If this is the case you have to factor the water into your final calculations, according to the instructions of the kit.

pH meters don't have this difficulty.

Pharmacies in the colonies do not provide such services, nor do most of them have the facilities (or knowledge) to do anything but take pills and liquids from one container and put them in another, with your name and physicians instructions copied word-for-word (plus transcription errors) from the prescription form. I suppose that's why we call them pharmacists, and not chemists.

Once the bottle has been opened, sodium hydroxide deteriorates fairly quickly. You can still use it, but you have to test the residual strength, and factor that into your test results. Therefore, it's not a good idea to purchase more than a year's supply at a time.

A Carlson kit cost $5-10, is easy to use, and is more than sufficient for a year's use for the home winemaker.

"Negodki" wrote "Pharmacies in the colonies do not provide such services, nor do most

Now Negodki...you're treading on dangerous ground with the assertion that US Pharmacists cannot provide NaOH solution for winemakers. I believe most would be glad to take some NaOH pellets from one container and dissolve in water in another container for you if you were willing to pay the price, which would be quite high these days. Modern US pharmacists have almost enough chemistry for a BS degree by the time they finish up undergrad school. However, the profession has evolved, like so many others, so that little compounding is done on site anymore.

Bill Frazier, Registered Pharmacist, MS Manager, Pharmaceutical Dosage Form Design Marion Laboratories, retired Presently making wine in Olathe, Kansas

"William Frazier" wrote:

I didn't mean to offend you Bill, and I'm well aware of the educational requirements for a pharmaceutical degree. However, I'm also aware that the average college graduate in the US can't spell, compose a grammatically-correct sentence, or remember his or her high-school chemistry. And even if our education WAS adequate, we tend to forget those formulae and procedures which we don't use.

Who remembers their differential and integral calculus? Who remembers the half-life of Californium or Berklium (or cares)? Who remembers what .1 normal means? Or whether one adds acid to water or the inverse? Or whether one drops the NaOH pellets into the water, or adds the water to pellets in a jar? [One of the two procedures is extremely dangerous!]

More to the point: I've asked pharmacists in the US for various chemicals and formulations and been horrified at their responses. For example:

• I asked for "metholated spirits" and received menthol! And when I attempted to clarify that metholated spirits is CH3OH, and doesn't contain any menthol, I was told "I have a degree in chemistry. Don't argue with me."
• I asked for "metholated spirits" at another pharmacy, and they had no idea what it was, or where to obtain it.
• I asked for sodium nitrate, and received potassium nitrate.
• My physician requested that the pharmacy prepare a more fluid (less viscous) form of hydrocortisone lotion, and they were unable to do it! I had to buy hydrocortisone and mix it with the isopropyl myself. I guess all those years at UCLA finally paid off: I can mix two substances together!
• And yesterday I was told by a Walmart pharmacist that he was unable to sell me a 6-oz plastic bottle, because it could be used for selling drugs!

You may be an exception, but very few pharmacies will do any formulation, and --- since they don't do it on a regular basis -- they probably lack the knowledge (that comes only from recent experience) to do so.

There is no way I am going to ask the average pharmacist to "take NaOH pellets from one container and dissolve in water in another container". I wouldn't want to be in the same room when he did it. And I wouldn't trust the formulation. I might get H2SO4 instead of NaOH, or I might get 10% NaOH rather than .1 normal.

Furthermore, I would be very surprised if the local pharmacy has any NaOH pellets to dissolve. Of course they could order them, and I might even get what I asked for eventually. But why not order from a chemical supplier or home brew who deals in these "exotic" items every day? And save money in the process.

Or, for that matter, why not purchase some "caustic soda" drain cleaner, and formulate your own?

Negodki wrote; "I didn't mean to offend you Bill, and I'm well aware of the

Negodki. I replied in good humor.

"I would be very surprised if the local pharmacy has any

infrequently requested item in a modern pharmacy. I went to Pharmacy School in the 1960s and in that era there was a lot of compounding work. We were rather well trained in that area.

"But why not order from a

your local homebrew/winemaking shops. If a local shop goes belly up be- cause of internet competition you won't be able to drop by for a few corks or packages of yeast.

Bill Frazier Olathe, Kansas

Who remembers (...) whether one drops the NaOH pellets into the water, or adds

I believe you're confused with strong acids.

Hmm yes, I believe it's called methylated spirit. You could have asked for denatured alcohol, or swabbing alcohol.

More of an advanced error, sodium or potassium wouldn't make so much of a difference in my medias. I would be really concerned if they would give you nitrite though!

Hope you cheered up with a good bottle of wine of own making ;-)

BTW, I wrote a resonse last year on this group about TA measurement standarisation, do a search for it and it will give you all the details you need.

Hope this helps, Rene.

No, Rene, I'm not confused (this time). Just as adding water to concentrated sulfuric acid results in an explosive exothermic reaction, adding water to concentrated NaOH results in an explosive thermic reaction (for similar reasons). I won't suggest you try it yourself, for I'm afraid that you might do so. Instead, have a look at the tiny little warning text on any bottle of Draino crystals, or Red Devil Lye, or in your Chem 1A laboratory manual. And wear goggles if you decide to test the theory empirically.

Please excuse me for the typo (metholated spirits v. methylated spirit). I'm quite sure that this wasn't the reason for the two pharmacies' inability to identify the substance requested, as the request was made orally.

"Denatured alcohol" is ETHYL alcohol that has been rendered unfit for drinking, so that the average hospital worker won't be too sorely tempted. It is NOT necessarily a solution of ethanol and methanol (which is what I required).

Similarly, if I asked for "swabbing alcohol" I would probably have received blank stares, or isopropyl --- which is used for "swabbing" in this country. If I asked in the Imperial Navy, I might receive a ration of rum. :)

??? An error is an error, and it is up to me, not you and not the chemist to determine if the substitution is adequate for the intended purpose. For someone with advanced hypertension or various other medical conditions, the difference between sodium and potassium can be life-threatening. Besides, the point is that if a pharmacist can make such an error, he/she can hardly be trusted to perform a formulation correctly.

Little Willie was a chemist, Little Willie is no more, What he thought was H20, Was H2SO4.

P.S. No reference to Bill intended. I didn't write the words. ;)

I think it were a good bottle of homemade sourmash, but it did the job. :)