If you aren’t re-proofing your ethanol after recovery, how many cycles of extraction/recovery are you using it for before you replace it?
Do you test for water content to establish when it comes time to replace your ETOH?
I’ve found that the amount I lose in process, offset by the amount I add, plus reproofing. Keeps my stuff viable somewhat indefinitely. I haven’t noticed any residuals left in the biomass after months on the “same” ethanol. Although it’s more than likely all been replaced over that time.
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This. 10% loss over the course of the week really doesn’t drop to much because it’s cycling somewhat. That being said if your getting 100% back and using The exact same etoh every time you get around 3-4 uses out of it before it’s dropped down to 170-180 proof
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I’ve ran the same ethanol at the very least 6 washes. Everytime it comes out of the rotovap, it’s always +195 proof, as seen on my gauge.
Granted it smells very terpy.
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you need to test your proof to make an informed decision here.
the moisture level of your biomass, how long you soak, and at what temperature, all effect how much water you pick up. how much of that comes over during recovery depends on how you recover.
even with only a single theoretical plate, many find they can get the bulk of their solvent off at 190 in an FFE or Rotovap.
it is knowing when to cut to tails (water and anything that boils higher than ethanol…heptane if you’re playing that game), as informed by your $10 proofing gauge, that allows you to run solvent indefinitely (with top up).
not using said $10 gauge means you’re not even sure you should reuse your solvent once.
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There will always be an issue with deproofing in continued usage of the same body of solvent. Exposure to atmos, biomass etc.
Distillation can reach a maximum of purity; 95-97%. Drying is nessessary to remove the remaining few points of water. Many ways to do it; mol. sieve, r.o. salt/dessicants, etc.
Easy way:
Calculate the volume of water to be removed and add 4.2g of calcium oxide/ ml h20 within the solvent
Let it precipitate for 12 hrs with occasional agitation.
You could siphon off the top to avoid the calcium hydroxide that has precipitated on the bottom(some solvent loss but avoids having water or slake in you b.f.) or distill it all to reclaim new proofed solvent.
I had someone around the copper pot tell me their dad, in a country that no longer exists, used to proof his Raikia by pouring it over concrete powder. I neither condemn nor condone this gypsy way.
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