The alcohol used for biodiesel production must be mixed
with the catalyst before adding the oil.
The mixture is stirred until the catalyst is completely
dissolved in the alcohol.
It must be noted that the alcohol must be water-free
(anhydrous) for the reasons explained in the previous paragraph.
Sodium and potassium hydroxides are among the most
widely used basic catalysts.
For production on an industrial scale, sodium or
potassium methoxides or methylates are commercially available.