Chief Science Officer
High Five Edibles
Santa Fe, NM
I like tea, so I boil a lot of water. I sometimes sit and watch it. It doesn’t make it boil any faster, but you learn a thing or two about the way vapor behaves. Vapor naturally goes up, not sideways.
Which is why I do vertical distillation instead of using rotary evaporators. There are applications in the pharmaceutical industry that require you to build a thin layer on the vessel wall, and rotovaps are great for that, but not for distilling ethanol. I know, it sucks to hear that, especially if you just bought a rotovap.
On top of that, these closed loops with vertical distillation units are self-cleaning. So, while you can spend two hours a week — about 100 hours each year —disassembling, cleaning and reassembling your rotovap, I spend about 10 minutes a week — less than 10 hours a year — cleaning the vertical unit.
That’s because the proper way to clean your rotary evaporator is to take it apart and wash each piece — the evaporation flask, condenser, collection flask and vapor tube — separately. It’s a lengthy process that includes cooling and disposal of contents and can even mean using a brush to remove stubborn residue.
For vertical distillation units, you just run some clean ethanol through it. Let one-third drain out so the bottom and drain port are clean, then reuse the other two-thirds from the collection vessel. Self-cleaning and now sterile, it’s ready to go for the next run. The current 50-liter unit returns more than 10 liters an hour. We fill and empty a 50-liter vessel twice in a shift. We are about to upgrade from glass to a stainless-steel condenser and are expecting to see an improved throughput.
(To be real, I do take the unit apart once or maybe twice a year just to make sure everything is in a steady state. And every month I check to make sure all the connections are tight.)
Now, that said, rotovaps are sideways so you can fill them all the way. Not that I top mine off, but it does hold more volume vertically, while still allowing room for liquid and vapor to rise. But if you take that sideways thing and put the top up, you essentially are now doing vertical distillation.