white layer in 50/50 test

[willbuild]

my feedstock was gloppy Chinese oil. I could not get a clear 3/27 pass with no fall out.
Kept adding Kohl with alittle methanol to no avail.
Added back first stage glyc did 5% pre wash left overnite, dropped glyc.
Moved to bubble wash tank and there was a thick layer of foam on the top that looked like expanding foam.
Skimmed of the top and left in a bucket for several hours still looked the same and did not break down.
I filtered the batch through j clothes then did several bubble washes till water was clear.
Left to settle for 2 weeks.
Now my 50/50 test shows a thin white layer and the water is slightly cloudy.
3/27 test not crystal clear.
Should i reprocess???

[willbuild]

And nothing in the bottom of selttling tank after two weeks

[Julian]

Not had the problem myself, but I think it's been suggested in the past that oil from Chinese restaurants can contain a high percentage of mono sodium glutamate.

I've got a feeling that Tony may have had some experience with this.

[willbuild]

They do "crispy fried seaweed" very popular. I think that seaweed has a high concentration of mono sodium glutamates, and my feed stock has a green tinge to it.

[Julian]

This from wikipedia ...
Chemical properties

MSG is freely soluble in water but not hygroscopic and practically insoluble in common organic solvents such as ether.

In general, MSG is stable under the conditions of regular food processing. During cooking, MSG does not decompose: Like other amino acids, browning or Maillard reactions will occur in the presence of sugars at very high temperatures.

So ... if it's stable during cooking and not effected by ether it will probably survive transesterification, not too sure about the catalyst.  But then its water soluble it should wash out.

Wonder it it's worth trying a water wash on the oil before processing, a couple of Dr Peppers should give a good indication ... might make a great wiki page if it proves to be successful.

[Julian]

They do "crispy fried seaweed" very popular. I think that seaweed has a high concentration of mono sodium glutamates, and my feed stock has a green tinge to it.

Wikipedia says it can be derived from seaweed, but isn't crispy fried seaweed really cabbage?

[willbuild]

Am on good terms with them so i will ask.
Would not want to stop using there oil as its one of my main collections.
maybe i could do something to elimate the in the process??

[Jamesrl]

I was under the impression that the white layer between bio and water in a 50/50 is mono and diglycerides, they're present due to the incomplete reaction.

[Julian]

I was under the impression that the white layer between bio and water in a 50/50 is mono and diglycerides, they're present due to the incomplete reaction.

These appear after an acid wash.

We really need a communal infrared spectrograph.  I'm sure collectively we could make one ... how difficult could it be?

This one only has a dozen parts or so ...

http://upload.wikimedia.org/wikipedia/commons/1/17/IR_spectroscopy_apparatus.svg

[willbuild]

I didt do an acid wash.
Am going to try dr pepper test on 1ltr  using 200ml methanol and 8grs? of Kohl

[Julian]

Sorry, my mistake!

Could quite well be as Jim describes, he has been known to get things right in the past.

Jim, is there any provenance for the layer being mono and diglycerides?

[Jamesrl]

Sorry, my mistake!

Could quite well be as Jim describes, he has been known to get things right in the past.

Jim, is there any provenance for the layer being mono and diglycerides?

It was  Mr GL himself  that informed the world as to what the white layer is, he also said that if you use distilled water for the test  it will enhance the result.

[Julian]

Sounds quite plausible and I've every respect for Graham, an exceptionally clever man, but any idea where he got the information from?

The longer I play this game the more I'm starting think many of the "rules" by which we work seem to originate from the annals of history without any provenance.  A bit like the 3/27 test being cloudy or coloured.  It would be great to have definitive proof of some of these things and stick them up on the wiki.

[Jamesrl]

Sounds quite plausible and I've every respect for Graham, an exceptionally clever man, but any idea where he got the information from?

The longer I play this game the more I'm starting think many of the "rules" by which we work seem to originate from the annals of history without any provenance.  A bit like the 3/27 test being cloudy or coloured.  It would be great to have definitive proof of some of these things and stick them up on the wiki.

I believe Graham is well versed in chemistry and has a knowledge of the subject way beyond your average numb nut.

[willbuild]

I didt do an acid wash.
Am going to try dr pepper test on 1ltr  using 200ml methanol and 8grs? of Kohl

checked this morning the test and had no glyc droping out, but clear pass on 3/27 test.
do i re process and should i use 20% meth.
the bio has changed from a light tan to a dark tan, is the glyc not droping?