Asahi LLE Project: Need help: Finding the viscosity of etho crude at various points and temps in distillation.

Does anyone have data points on the viscosity of crude ethanol extracts?
I realize there is a wide range of variables to account for, so any data (even empirical) is a great start.
Has anyone tried to measure the viscosity before and after distillation?

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can anyone provide links to the correct tooling/methodology to gather that data?

I have in the past requested a hotplate/stirrer combo that could have gathered that info, and send it via serial or bluetooth. $1500 seemed reasonable to me.

yeah no.

not sure that is was from heidolph Heidolph Instruments : Magnetic Stirrers but it might have been.

I repeatedly run into folks who misuse viscosity. usually they have it backwards. I suspect its the engine oil ads are to blame.

in addition to temperature, presumably that viscosity data also needs to be paired with reasonable quality potency data as well. further limiting your pool of possible providers…

Edit: pulling it from a motor driven device is obviously as simple as measuring current and doing math. which is why that measurement makes sense to build into a connected stirrer.

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The range of viscosity is from shatter like distillate to terp rich, runny, motor oil like crude.

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and if you warm it right, the distillate has a lower viscosity than that crude at 298oK :wink:

From my research yesterday, you can get a good idea using various drip over time equations & equipment. Also dropping a ball through and measuring how long it takes to fall plus a little math…

and then there’s electronic viscometers.

On the Heidolph stirrer, the precision model has a torque readout. I didn’t even think about this. A lab in southern Oregon uses one to know when they have added the right amount of terps back into their product for their carts. In theory you could try and take the torque readout and infer a viscosity using a few known substances but at $4,500 (just the stirrer, no hotplate) :man_shrugging: get an IKA


Molasses has a viscosity of about 500 poises and most crude is somewhere near molasses in viscosity, right?

Edit: At room temp


I wonder if it was that easy why the guys at heidolph chose to measure in torque instead of viscosity. The obvious answer is differences in stir bars. It would seem like a no brainer to make a ‘viscosity attachment’ if they could.

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you’re right. I probably figured torque would give me a decent proxy for viscosity if all else remained the same. was going to use it to figure out when I’d removed the right amount of etoh to hit the oven shelves. got good at seeing it in the rotovap instead.

it’s been two years since the ad came across my desk. it was german made. blue. and $1500 as I recall.

Edit: came across my desk 12/13/2015 torque. and weight!

price has dropped to $1099


poises? New vocab word :slight_smile:

Thanks @Future!

@sidco I assume you need temp curves for this right?

Edit: and “I lost my poise” suddenly makes sense as a euphemism for “I had a melt down!”

Edit: of course I’m now reading about

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I think what is more important is remaining solvent over viscosity. Temp does matter in changing viscosity, but I was expecting a pretty wide range from the internet peeps and hoping to get a baseline idea of temp (for instance, at room temp) has a cool chart that might get some numbers on the table (and help me buy a viscometer if I need it) The boss wants to order one of those IKA systems - 1 cP (centipoise) = 1 mPas (millipascal-second) so “Viscosity measuring range: 1 - 6,000,000 mPas” should do it for our application by my math

Sounds like Karo Syrup 5,000 cps, so that is about right according to the chart (at room temp.)

same folks who made the stir plate I linked.
not German. Chinese.


Measuring torque with a magnetic stir bar is racking my mind a bit.

feed it water, feed it milk, feed it honey, and their ilk.
spin it round. do the math. ethanol. then short path.

Edit: which I think means build a lookup table. or an equation that fits. then gather your data as you boil off the ethanol (monitoring weight loss!). but I could be misinterpreting.

there is also no mention of vac, which would be required if you wanted to do the evap at room temp.


rotational viscometers are where it’s at…:slight_smile:


Did you ever come up with a confirmed number on centipoise for crude or distillate? id imagine 15,000 and 5,000 respectively, but im wondering if you ever got concrete data

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