I have just processed a batch with dkenny's simple method of acid esterfication and the Biodiesel seems to be very dark.

When the Acid/Methanol were mixed with the oil... the oil turned very dark (black) like the acid burned it.

Everything went quite well.

Started off with oil that Titrated @ 16.4 KOH and the acid process seemed to halt at 4.1 KOH which I thought wasn't too bad for such stinky oil with black floaties in it (removed of course). Oh, and I must add when I added the Acid/Methanol it stank 10x worse.

Even after 12 hours sitting, there was no real separation except for some methanol floating on top (perhaps?).

I did my base process based on the 4.1 KOH end value and it too went well.

I did the 5% pre-wash. Drain.

At this point my yield was excellent 90%+ and I am happy with that from such oil.

I only have a relatively small wash tank 200L (same size as my reactor -- they are 200L HDPE drums decked out like an Appleseed) and I usually get about 150L of Biodiesel per batch. So my washes are only 50L at a time... so I do a few extra.

I pump wash!!! So to be kind on the first wash, when there might be quite a bit of gloop producing glycerin and soap. I 1/4 fill the wash tank pass the dirty Biodiesel THROUGH the water and then pump for about 5-10 minutes (Till the water gets murky).

Subsequent washes, I hammer the Biodiesel. Fill- pump on - walk away - oops is that still washing (1-2 hours later). And it separates quickly 1-2 hours. As I reach "clean", when it separates, the Biodiesel is visibly "half dry" already.

To dry, I remove all the water from the tank and pump for a few hours forcing room temperature air through the top of the wash tank... and it is done.

Using the acid/base process everything has still gone like clockwork.

Should I be worried about the color of the Biodiesel?

I have attached a picture of what it looks like after 2nd wash compared to my usual end result.

P1000421.JPG (1,065 Kb, 83 downloads) Color

It looks excellent!

I should make it clear...
The finished biodiesel sample is what I usually get after "single pass base only", which I use on oil up to about 5 KOH which is the worst I usually have. This lot was 16.4 KOH!

That is the darker sample (after 2nd wash) next to the first, and by the way it still stinks after 2nd wash and the methanol is quite evident. The smell doesn't bother me, I keep washing until I am tempted to drink it!!! When my senses tell me "it's good food"... and it is washing 50% dry (top half is clear, not cloudy after 30 min separating).

I love the fact that you wash biodiesel dry!

Does it still look ok, even though it is darker at this stage?

I've seen a lot darker BD that passes 3/27.

When you have different sources you will see a lot of different colors. Sometimes it's even difficult to see the seperation line at the glycerin layer.

As long as your finished fuel passes 3/27, I say color means nothing. I have noticed too that acid/base processing can make some very dark bio, but it runs fine in my trucks.

That biodiesel is not that dark. I've seen ASTM spec biodiesel that was practically an opaque black, with light honey-colored glycerin sitting beneath it.

glad to hear it worked..

biodiesel has no normal color if it made from WVO.
the color can range from light to very dark..the same as the rest are saying.

-dkenny