The World Famous Chopstick Titration Technique (Pat Pend)
Titration is a simple test to determine how much NaOH/KOH is required to neutralize the FFA's in the oil. This amount of NaOH/KOH is added to the Methanol as an extra amount beyond what is required to perform the reaction.

I originally Wrote this procedure up about 2 years ago in another thread.
I have recently been doing some testing and up-dating and have decided to give this procedure it's own thread.

With ideas unashamedly borrowed from several different people whom I will gladly share all my royalties with on this Patent just as soon as they send me a one-time registration fee of $1000 US.
Please Note
I have written this procedure for titrations using NaOH.
If you are going to use KOH in the reaction, just substitute KOH for the NaOH in the directions.
Also change the base amount from 5g NaOH to 7g KOH adjusted up if the purity is less than 99%.

Please Note
During the titration, depending on which alcohol you use, the oil might NOT disolve into the Alcohol. That is fine, all the alcohol is doing is washing the FFA's out of the oil.

MATERIALS NEEDED

ALCOHOL
1- bottle of isopropyl alcohol (isopropanol).
In the USA, Iso-HEET® Premium Fuel System Dryer & Antifreeze, 12 fl. oz. in the red bottle is available at all fine auto shops and is about 99% isopropyl alcohol. $2.00.
Also, in the USA rubbing alcohol is Isopropyl alcohol 70% purity will work fine.
OR
1- bottle of Ethyl Alcohol (Ethanol).
In Australia and many other countries, "methylated spirits", commonly called "Metho" is 95% Ethanol and only about $2 a litre.

1 Box Flat Wooden Tooth Picks

INDICATOR
1 container of Ground Turmeric
Turmeric is a spice and is readily obtainable from all Fine Grocery Stores.
OR
1- bottle of Phenol Red
Phenol Red is normally used to check the pH of swimming pools, is a liquid, and is easily available from all fine Pool Shops.
OR
1- bottle 1% Phenolpthalein indicator
Good luck finding it.

1-litre of "Titrating Fluid"
"Titrating Fluid" is made by dissolving 1g NaOH into 1 litre of distilled or Rain Water. In a pinch, tap water will work too.
As you might not have particularly accurate scales, one way of achieving this is to measure out 10g NaOH and dissolve this into 1 litre of distilled or rain water.
Now take 100ml of this water and mix with 900ml distilled or rain water.
You now have pretty close to the 1g NaOH in 1 litre of distilled or rain water.
Or, go to your local pharmacist or High School Science Dept and ask them to do the measuring for you.

EQUIPMENT NEEDED

1- 50ml medicine measuring cup with ml graduations marked on the side. The tapered ones are best. From local pharmacy

1- glass 1 ml eyedropper with graduations marked on the side. From local pharmacy

1- 3ml Syringe (no sharp) From local pharmacy

1- plastic chopstick From local chinese restaurant.

Total equipment cost should be under $10 and is good for hundreds of titrations.
No fair counting the cost of a meal at your favourite Chinese shop to steal a chopstick.

Be aware that because Phenol Red, Turmeric and phenolphthalein all change colours at a different pH, a slightly different titration technique is required with each one.

THE PROCEDURE USING PHENOLPTHALEIN

1. Pour about 10ml of room temp alcohol (Isopropyl or Ethanol} into the 50 ml medicine measuring cup.

2. Place 3 or 5 drops of Phenopthalein into alcohol

3. Fill the syringe with "Titrating Fluid" and while using the chopstick to vigorously stir, slowly, drop by drop, add "Titrating Fluid" to the alcohol until the alcohol just starts to turn a permanent pink colour and then STOP.
You have just performed the "Blank Titration" The "Blank Titration" neutralizes any acid that may be in the alcohol.
You are now ready to titrate the oil in question.

4 Using the eyedropper, add exactly 1ml of the oil to be titrated to the alcohol.

5. Place into microwave oven and microwave until the First Bubble appears (5 or 10 seconds)STOP Note: This step is not absolutely necessary.

6. Now, always filling the syringe with exactly 3ml of "Titrating Fluid", start dropping the "Titrating Fluid" into the medicine measure while stirring vigorously with the chopstick.
I find an up and down motion which breaks the oil up against the bottom of the medicine glass works best.
Do not stop stirring

7. Keep track of how many ml of "Titrating Fluid" is needed for the liquid to turn and remain a light pink for about 20 seconds before the colour fades..

This is your titration number which you then add to 5 to find out how many grams of NaOH is needed per litre of WVO.

It takes longer to read it than to do it.

THE PROCEDURE USING TURMERIC

1. Pour about 10ml of room temp alcohol (Isopropyl or Ethanol} into the 50 ml medicine measuring cup.

2. Scoop out a small amount of Ground Turmeric on the wide end of a toothpick.
Put the turmeric into the alcohol and use the Chopstick to stir it well into the Alcohol for about 5 seconds.
The Alcohol should now be a nice yellow colour.

3 Fill the syringe with "Titrating Fluid" and while using the chopstick to vigorously stir, slowly, drop by drop, add "Titrating Fluid" to the alcohol until the alcohol just starts to turn a permanent pink colour and then STOP.
You have just performed the "Blank Titration" The "Blank Titration" neutralizes any acid that may be in the alcohol.
You are now ready to titrate the oil in question.

4 Using the eyedropper, add exactly 1ml of the oil to be titrated to the alcohol.

5. Place into microwave oven and microwave until the First Bubble appears (5 or 10 seconds)STOP Note: This step is not absolutely necessary.

6. Now, always filling the syringe with exactly 3ml of "Titrating Fluid", start dropping the "Titrating Fluid" into the medicine measure while stirring vigorously with the chopstick.
I find an up and down motion which breaks the oil up against the bottom of the medicine glass works best.
Do not stop stirring

7. Keep track of how many ml of "Titrating Fluid" is needed for the liquid to turn and remain it's darkest red for 20 seconds before the colour fades..

This is your titration number which you then add to 5 to find out how many grams of NaOH is needed per litre of WVO.

It takes longer to read it than to do it.

THE PROCEDURE USING PHENOL RED

1. Pour about 10ml of room temp alcohol (Isopropyl or Ethanol} into the 50 ml medicine measuring cup.

2. Add 3 to 5 drops of phenol red to the alcohol.

3 Fill the syringe with "Titrating Fluid" and while using the chopstick to vigorously stir, slowly, drop by drop, add "Titrating Fluid" to the alcohol until the alcohol just starts to turn a permanent pink colour and then STOP.
You have just performed the "Blank Titration" The "Blank Titration" neutralizes any acid that may be in the alcohol.
You are now ready to titrate the oil in question.

4 Using the eyedropper, add exactly 1ml of the oil to be titrated to the alcohol.

5. Place into microwave oven and microwave until the First Bubble appears (5 or 10 seconds)STOP Note: This step is not absolutely necessary.

6. Now, always filling the syringe with exactly 3ml of Titrating Fluid, start dropping the Titrating fluid into the medicine measure while stirring vigorously with the chopstick.
I find an up and down motion which breaks the oil up against the bottom of the medicine glass works best.
Do not stop stirring

7. Keep track of how many ml of "Titrating Fluid" is needed for the liquid to turn and remain its deepest, darkest purple/ red for at least one minute.

This is your titration number which you then add to 5 to find out how many grams of NaOH is needed per litre of WVO.

It takes longer to read it than to do it.

While I am assured that the Turmeric Titration is more accurate than using Phenol red, and phenolpthalein is more accurate still, tests I have performed shows that Both Turmeric and Phenol Red give virtually identical titration results and are also virtually identical to the results obtained when using Phenolphthalein.

This message has been edited. Last edited by: Tilly,

Nice upgrade Rev.

Bump. Why not replace the Sticky ?

Here is another comparison of indicators, copied from "How to use turmeric".

There has been some discussion of the errors with different indicators. In particular the point about pushing the indicator past its optimum colour change has been discussed. In the case of phenol red and turmeric the mid point is orange and the full colour change is red. In the case of thymol blue the mid point is olive-green and the full colour change is blue-green (it would be pure blue except that the veg oil is itself yellow).

I have now done a number of measurements of a UCO and got the following results for FFA%:

Indicator ________Mid__Full
phenol red ______3.85__3.94
turmeric ________3.97__4.06
thymol blue _____4.07__4.16
phenolphthalein_____4.14

In each case the colour at the mid point had to last for 20 seconds. When pushed to the full colour change the colour persists for many minutes. Phenolphthalein has no mid colour as it is colourless in acid whereas the others are all yellow.

Thymol blue seems to give about the same reading as phenolphthalein if pushed to blue-green as near as I could measure.

There is some error with both phenol red and turmeric even when pushed to the full colour change. The error with turmeric is about half that with phenol red. As it is cheaper than phenol red and easier to get it appears to be the preferred indicator if phenolphthalein and thymol blue are not available. In this test turmeric when pushed to red gave the same result as phenolphthalein if expressed to one decimal place.

Neutral,

I've never seen phenol red give a red or orange color change. I've never heard of anyone else getting orange with phenol red either.

here's a discussion on another forum today where this issue came up (Billy Bob is of course Tilly):
http://www.forums.biodieselnow.com/topic.asp?TOPIC_ID=7468

Mark

GM, go to your pool shop and look at the colour chart used to get the pH right in a swimming pool. You will see the range is from yellow to red passing through orange. A careful hand can achieve this range will veg oil.

the other big issue tat we've discussed in other threads is that the error is larger with high FFA oil. I really dont' think there's ANY issue with a difference between 3.85 and 4.14 , but there's a much larger issue of (if memory serves) something like a 2 or 3 ml spread in results with different indicators if working with really high FFA oil. I was playing with some 12 and 18 and 22 ml oils last month when I was fooling with acid-base processes, and there was a large difference between titrations going from phenol red to turmeric or phenolpthaleine.


Of course I believe that with high FFA oil there are worse things to worry about quality-wise than just titration accuracy, like whether you'll succeed in making fuel at all.

Mark

neutral, how can these results be compared to actual numbers? GC?

GM,

I had a look at the biodiesel now forum and noted the comment about there being no shades of colour with phenolphthalein. I think that may be why it is universally used in industry for FFA. There can be no argument about what you are looking for, just colour or no colour. The criterion then becomes how long the colour persists for, which can be measured.

I agree with you that for oils of low FFA it won't matter much which indicator you use as the bulk of the NaOH used is derived from the base value, not the titration, especially if you use 5g rather than 3.5g for the base.

Dropout,

For oils of low FFA, using a little less NaOH will only result in a slight reduction in conversion, see "How much NaOH", but for high FFA oils it may make the difference between success and failure, as can be seen by studying the experiment reported by dkenny.

Hello Mark

If you are following the titrating instructions posted on the CBT web site when titrating with Phenol Red, you are not using the correct procedure.
Have a look at the World Famous Chopstick Titration Technique (Pat Pend) for the correct procedure.

Mark can you make this a sticky thread?

I haven't heard of Thymol Blue being used before... however, I've got some! I sell beer and wine making supplies. We've got a test kit that includes a graduated cylinder, thymol blue, and litmus papers. The procedure goes like this:

1) Add sample (usually grape juice, but WVO/isopropanol in this case) up to the "0" (zero) line in the graduated cylinder.

2) Add Blue solution (has a dropper-top) until blue-green change is permanent.

3) If you aren't sure, tear off a piece of litmus paper and dip into the sample. If it turns pink, the test is not complete -- add more blue.

The cylinder is graduated at every ml. The benefit being that you don't have to measure the amount of blue solution that it takes to change color. You just add it until the color changes and read the number at the level in the cylinder.

Am I right in assuming that this will work for my WVO? It would be easy and cheap for me, since I already have one... and a supply of the blue solution!

My question: Can the result be read the same? In other words, if it takes 2.5ml of blue solution to get a color change, then I need to add 2.5g/L to the base just like a phenolpthalein test? The new ones don't use sodium hydroxide -- just the blue stuff. How does that equates to NaOH or KOH titration. I'll be using KOH when I get my processor together.


BTW, the old-style titration kits for home wine-making used phenolpthalein and sodium hydroxide. The big problem with those was that they only had a few months shelf life, then they would lose accuracy in a big way. I'm pretty sure it was the phenolpthalein that lost it potency.

I sell it on my homebrew shop's web site ($15.99). I don't know if promoting my store on here is against the rules. If anyone is interested, let me know and I can send you the link... or a moderator can let me know if it's okay to post it here.

FYI, I believe it's 10ml up to the "0" mark on the graduated cylinder, and it allows fr up to 20ml of solution to be added. Hopefully, nobody has WVO that titrates that high! I'll try to post a pic of the setup.

Okay... where am I going wrong?

I am using the test kit I mentioned above to test some WVO. I heated a small sample of the WVO to remove water (not much there). Basically, I followed the same steps as for Phenol Red.

I used 1 ml of WVO + 9ml of 70% isopropanol.
I added blue solution until color change.
I tested with my pH meter. It is supposed to be at pH 7.0 when the test is complete... however, I got a reading of 12+!!! I tried it again, this time I stopped when the color change was not quite permanent. The pH was about 8.3.

Should I be testing pure WVO instead of WVO+isopropanol? Is the 70% throwing it off? The WVO+isopropanol is at pH 5.1 before the test.

I have used this test kit for wine many times. What's the procedure for WVO testing with this kind of kit?

I know that when using this test for dark red wines (where it is difficult to see the color change) you can dilute the wine with water... but the test results must be multiplied back up. In other words, if you cut the wine 1:1 with water, you must double the answer... if you cut the wine 1:2 with water, you must triple the answer.

This procedure differs from the method used in biodiesel in two ways: the thymol blue appears to be in the solution you add and you buy the solution already made up. An essential part of the proper process is in knowing the concentration of the solution you add. If you don't know that there is no way to work out how to do it.

Also it costs something to buy a ready made solution. If you make your own it costs virtually nothing. A jar of turmeric will last a lifetime. I doubt whether phenolphthalein goes off in a decade but it might if in a solution containing NaOH. It seems a better idea to me to have the indicator separate. That is the usual way it is done.

The pH you are looking for is not 7 but 8 to 9.

Tilly, I think you should correct the spelling of isopropanol at the top of your wonderful method!

great one, rev. Tilly
I should have been using this to begin with.
Very clear and concise, thanks.
I want to look at your testing method. Can you direct me to it? The one I mean is the ATSM (sp) test for soap. I want to check my latest 25 gallon batch to see why I keep getting emulsions. Although the last batch was not as bad as the prior batch, it does not look right yet. I added water but didn't bubble. Still the biodiesel got very cloudy.
I take what you say with the utmost confidence.
Thanks again for everything.
Brian Rodgers

Hello Brian

There are two backyard tests for Conversion.
World Famous Dr Pepper Viscosimeter (Pat Pend)

World Famous Dr Pepper ASTM Reprocess Technique (Pat Pend)

Thank you St. Tilly
I read the viscosimeter thread yeasterday while I was looking for World Famous Dr Pepper ASTM Reprocess Technique (Pat Pend). Very good stuff. I kidded with my wife about the chemicals because she was concerned I was wondeing about using muriatic acid for breaking the emulsion. She said you really like that atuff huh? Hehe
Anyway thanks.
So I think it is obvious I have soap when every bit of water makes emulsions. Besides finding out where the soap came from I focused on cleaning it out of the last batch before I begin again. Reprocessing looks like the answer I need here.
Thanks
Brian Rodgers

Just wanted to say...

Till today I deferred all titration to my husband, the chemist, in our making biodiesel. Since he is on a trip for 2 weeks and won't be back soon, today I decided to give'er a go myself. My husband has been frustrated with reading the results with other methods, but I could easily read the results with this method! I will certainly recommend the chopstick method to him.

BTW, in our case, the oil is very good stuff so I knew it would titrate low. I only had to add 1 drop of titration fluid to finish the blank titration. It took only .5 mls to go deep red. Very clearly defined results, nothing uncertain about it.

Thanks for a very good method!

bb