I believe that is Zeolite 3A is the last stage that distilleries use to get ETOH from 195 to 200 proof.
If you are doing ETOH extractions, you should run your ETOH through molsiv every time, after you recover it from your roto.
We run ours through Zeolite 3A, 12X and handful of silica gel beads after every extraction. By now there’s probably not much heptane left, what we have was much cheaper than real food-grade from upta Bangor distillery. So it is also a cheaper way to get almost food-grade ETOH.
The column will warm up if you are doing it right. Don’t just suck it all through, it takes time to work. We let it dribble slowly through the chromo column without any vac then test each batch with a distillers gauge thingie.
We notice a performance difference between 195 and 200 proof. 200 pulls more material more easily. Below 190 performs much less efficiently.
If you just keep using the same ETOH without rehabbing it, eventually you will get what looks like white wine instead of moose piss.
You only need 3A to pull off water and thus recondition your ETOH. The 12X specifically targets heptane.