BioDiesel Class 101
Class # 3
Titration is a very simple
chemical test with a complex sounding name. This test is done to determine what the pH balance of the material
in question is at, in layman's
terms, how acid or base the item is.
The Transesterification process requires
a slight Base pH condition. Since we
use WVO, it is important for us to check the pH of the oil because the act of heating &
cooking food with an oil produces acids called FFA or Free Fatty Acids. As the FFA
causes our WVO to become more & more acidic over time. If
under less than ideal pH conditions we will produce less BioDiesel methyl
ester & have left over unconverted fats or if we use too much Lye we will make
excess soap. The
process will always produce some soap, we just want to keep it to a minimum.
Common pH test strips are not sensitive or reliable enough for making testing
with & it
is questionable if a pH electrode would work well or very long when
contaminated by oil, so that leaves us with the cheap but simple test called
titration. We give more details than those contained below in
our PGB book.
To titrate you use a
simple pH indicator solution such as phenophaline solution or red cabbage juice
to give an indication how acid or base a solution is by color change. You also
use a standardized (Lye) reference
solution to determine how much Lye you will require.
How to Titrate (basics)
Get some Iso-Heet brand isopropanol alcohol
& measure out 10ml into a clean baby food jar.
Place 3 drops of pH indicator solution
such as Phenophaline solution into the
alcohol in the jar & mix well.
Start adding .1% Standardized
drop by drop into the prepared
alcohol/phenophaline mixture. Swirl the mixture as you add in the
reference solution & watch carefully for a pink color change, stop adding
the solution as soon as this occurs. This neutralizes any acid in the
Now measure out 1ml of the WVO to be
tested & place it into the baby food jar with the alcohol mixture. You
want this mixed up very well so make sure you swirl or stir it up until the
alcohol & oil are totally mixed, this is very important!
Once mixed, start swirling the mixture
while you ad in the standardized lye solution drop by drop. You want to count the number of drops it takes to make the
solution change it's color to pink for 10 seconds. Each 1ml of standardized
solution used equals 1 gram of Lye to be used per liter of WVO you wish to
Brand new vegetable oil does not contain
FFA from cooking so it does not need to be titrated because it has not been used
to cook with & we know the ph. The amount of Lye required to reach the pH
needed to process new oil into BioDiesel is
between 3.5 & 5 grams of Sodium Hydroxide per Liter of oil. When using WVO, you take
the number that it titrated at & add between 3.5 & 5 grams to this number, you then multiply this
number times the number of Liters of WVO that you intend to process & this is
the weight in grams of Sodium Hydroxide you will require to make your BioDiesel.
And you thought we forgot.....
What does Titration do?
Name 2 pH indicator solutions?
What are you really doing when you
Blank the solution?
What does FFA mean?
How many seconds does the standardized
solution need to hold the pink color for in to know how much Lye to use per
liter when making BioDiesel?
What kind of alcohol is used when
How many grams of Lye are required to
convert the new base oil?
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