NGS temperature

[Boxertail]

I recently aquired an 5 gal alembic pot and a electric plate for indoor
use. Prior to this all my experience is with a colomn still outdoors over a
propane burner. I am producing absinthe and using a NGS (everclear) 190
proof as a base spirit and infusing herbs through the distillation. Every
run on my older colomn still my runs would produce at about 170-175
degrees on the top temp reading. My new alembic still started producing at 147 and remained at 150
till I reach the tails. The part I am struggling with is the safety of this
temperature. Can you produce methanol from Pure ethanol? Is it safe to have
a run at 150 degrees? If it is safe do you have an explanation as to why
it is different?

[still_stirrin]

...Can you produce methanol from Pure ethanol?

Nope.

Methanol is a fermentation byproduct. If you’ve purchased genuine grain neutral spirit (GNS), then there is no measurable methanol in it. Typically, methanol is produced in fruit ferments when the pulp is left in during the ferment.

...Is it safe to have a run at 150 degrees? If it is safe do you have an explanation as to why
it is different?

Well, at 150*F, you’re not going to get alcohol out of the wash.

In fact, it’s highly unlikely that it would even boil. I’m betting your thermometer is wrong. Go check the calibration in a pan of boiling water and a glass of ice water. It’s probably way off.
ss

[Boxertail]

Thanks still_stirrin Wow. Such a fast response. Thanks. In regards to the fermintation proccess I do a similar masseration using herbs typical to absinthe for 24hrs. Is there any chance of fermintation here?
2nd in regards to the temperature test. I would agree with you that it was definitely a strange occurrence. I'm not quite sure how I will test this temperature gauge as it is welded into the top of my still. Do you think it would be helpful to check the hot plate temperature? Maybe this could give me an idea of what sort of temperature it is reaching...

[still_stirrin]

In regards to the fermintation proccess I do a similar masseration (maceration??) using herbs typical to absinthe for 24hrs. Is there any chance of fermintation here?

Nope. The alcohol is a damn good anticeptic.

Do you think it would be helpful to check the hot plate temperature? Maybe this could give me an idea of what sort of temperature it is reaching...

Nope. Element temperature has little to do with the wash’s boiling temperature. If the thermometer in the top of the column is permanent, and reading incorrectly, I’d suggest forgetting about it. You really don’t need to know the temperature of the vapor to run a distillation. You just need control of the heat input (watts, not temperature) and the control of the condensers coolant flow, ie - the reflux condenser and the product condenser. And I’d recommend separate controls for each of them.

If you run a potstill only, then you definitely don’t need a thermometer. It’ll just confuse you.

I suggest you spend some time reading Cranky’s Spoon Feed thread hotlinked in my signature. You have a lot to learn about the distillation processes.
ss

p.s.- edited to add: an alembic still is a “potstill” with a onion cap on the boiler. So, the thermometer in the gooseneck of your alembic is NOT necessary to properly run the still. It gives an information data point only. But it should not be used to determine when to make cuts. It’ll only mislead you and cause you to chase your tail.

[Boxertail]

Again really appreciate your help. Looking forward to the ever expanding wealth of knowledge. Have a great day.

[Skipper1953]

I'm not quite sure how I will test this temperature gauge as it is welded into the top of my still.

Try boiling some plain old water. See how far off it is from 212°. If it's actually welded or soldered into your column, it could very well be damaged.