A few thoughts on the 3/27 test

[Julian]

Had a batch yesterday where the glycerin was extremely slow to drop.  I noticed that after a good human centrifuging very little glycerin separated, but leaving it for several hours produced a normal quantity.

I had great difficulty in getting a good 3/27 pass, but I'm now wondering if that was due to there being glycerin present.  Has anyone done any tests to show what the effect of glycerin in a 3/27 is?

This may have been covered before, but I recon the 27 bit of the test can only be a minimum.  The logic being if I have a test with some drop out, adding additional methanol shouldn't effect the result.  So instead of measuring exactly 27ml of methanol, as I've been doing for many years, filling the test container with approximately 30ml (the next higher graduation) should still yield a viable result.

Anyone got any ideas why the glycerin in this batch was slow to separate, I've not had this before?  Unusually there was a very dark (almost black) phase between the glycerin and the bio.

[willbuild]

I also get a black phase between bio and glycerin and also a slow drop. i find it tends to happen with high tit oils.
I have just done a dr pepper test on a batch that i've just dryed and its slow to separate with the black layer. I used 15grs of Kohl and 17% meths and had a fallout of 2 on a 90/10 test.
There was a thread on here a few months ago re 27/3 test and the conclusion as far as i remember was to to be over rather than under with the meths.

[Julian]

The oil titrated higher than my normal oil, but not excessively so.

Black phase is new to me after nearly 150 batches!

[willbuild]

Maybe its my source, I get 75% from the same place, very wet high tit, fryed chicken place.
But i live with it as i only pay 10ppl and is 5 mins from home.
If the batch is made up with 50% or less of there oil i dont get thin black layer.

[Chug]

done loadsa tests on 3/27, soap, glyc etc but some of the results posts got lost when paddy changed forum software, along with many other testing results that I didn't have a copy of! anyway IIRC, glyc dissolves in bio and leaves it clear but does 'colour' the meth like bio does, was the glyc slow to settle after getting 3/27 pass?


right finally found some test stuff.
http://www.vegetableoildiesel.co.uk/mybbforum/showthread.php?tid=9490&highlight=3%2F27

[Jamesrl]

Well done Chug, saves me writing it up.

Anyway were y'bin lately y'little sod?

[Julian]

That's an interesting thread, Chug.

I think I post on here a while back trying to find out where the idea that a cloudy result with no drop out = mono and diglycerides and no one could tell me where it came from.  I did a great deal of research to go as far back as I could and found an archived version of Jan's email detailing the original test and there was no mention of it.  I put a copy on the wiki here ... http://www.biopowered.co.uk/wiki/3/27_test ... bottom of the page.

Jan doesn't even confirm that drop out is necessarily oil, he just says "contaminates" and mentions "incomplete conversion".

It struck me at the time that far more was being read into the test than was originally intended.

I'm not being obtuse, and I appreciate is a while ago, but can you remember where the info for these statements came from?

High conversion samples will produce no fall out, no matter how much extra bio is added.
Low conversion samples will produce fall out with as little as 0.25ml extra bio added

GC testing has shown that Monoglycerides remain in the methanol and that triglycerides and diglycerides fall out to the bottom, this could also be time dependent. The triglycerides fall out almost immediately; while the diglycerides take longer and the monoglycerides may fall out after a day or so.

Mono and diglycerides can cause haze/cloudiness

And different oils/fats have different degrees of solubility in methanol? Could polyunsaturated oil be more soluble than saturated or hydrogenated oils/fats?

To add to my current experiences, the 3/27 pass I got is now showing a very tiny amount of drop out, not of liquid but solids (fluffy sort of stuff).  I don't think its similar to what I've had in the past which I believe was flour that had persisted throughout processing.

[Jamesrl]

I'm not being obtuse.

Of course not, more a cute, if I spelt that right.

[Chug]

Blimey Julian, that was a few years back, but most of my conclusions were gleaned from trying what others had posted about on infopop and here and other forums, and the GC testing info though most probably came from infopop as nobody was doing it here and I definitely aint got GC kit, and it would have been from a respected member, most likely one of the original bio tutorial bods.

[Julian]

I trawled infopop and other forums for hours and couldn't find anything remotely like that.

[Chug]

I found it in under a minute

[Head Womble]

Did your dropout look like this

[Julian]

I found it in under a minute

Not your thread!

I was looking for the original published results from which you got the info.

[Julian]

Did your dropout look like this

Yes, a little, but not as white, more bio coloured.

What do you recon that is ... did you sneeze into the centrifuge tube?

[Jamesrl]

Did your dropout look like this

Yes, a little, but not as white, more bio coloured.

What do you recon that is ... did you sneeze into the centrifuge tube?

Or is it something else?

Well you never know, he does get VERY exited IF he gets a clear 10/90.