Current Solvent Ratio in CLS

We like to occasionally use mixtures of n-butane/propane for our closed loop live resin extraction. Our supplier will give it to us pre-mixed or separate. Does anyone have a good method for determining the current solvent mix in your solvent tank? We start with 70/30, but I’m sure after even just one run, that ratio is off. I’ve been racking my brain trying to figure out a reliable and safe way to figure out what I have inside my solvent tank at any given time. Is there a chart to correlate the mixture to pressure and temperature? I haven’t been able to locate one that was useful to me. Thanks!

1 Like

Given the way vapor pressure varies with temperature and mol fraction of the various components, I’m sure there is a way of using pressure readings at a couple of well chosen temperatures and some maths to figure it out.

if I’d had more coffee I might even do something stupid like make a stab at the math. :wink:

this might help get you started


How large is your running tank? I use a 70/30 blend as well, order in tanks pre-mixed and fill a significantly smaller tank off the premixed. As the day drags on the propane % decreases but typically I only get a days worth of running of a single fill.

Add back propane

When the yield starts getting fucky add back butane

Add back regularly so it’s in smaller amounts. I’d do it daily


Really need to sit down and teach this maths to my phone at some point…anyone done that yet?!?


Just run isobutane…

Fuck blends imo


This is the way.

im pretty sure the propane goes away first.