Why wont my Temp stabilize

[Austin Nichols]

I Tried out my LM/VM boka for it's first true run today with 40 liters of the all bran recipe, but could not get the temp to hold still no matter what I tried.

OK first up I've read the topics on VM & LM operation in the reading lounge and thought I had followed the instructions properly for both configurations.

I will try give as much detail as I can about the run and what I did.

I had the 1 meter section of the column packed with scrubbers and could easily breath through it.
My cooling/water/condenser system is great, adjustable, and very precise.

OK so I've brought her up to the boiling point of 78.6c and left it to do it's thing for an hour just like in the tutorial, cracked the needle on the boka LM part to drain foreshots and heads, just 1 drip per second, I took 200ml off and chucked it on an ants nest. Then took another 500ml of heads until I thought I had most of it, it got upto 81 degrees c by this stage, so close valve and leave it for about 10 mins to stabilize again.

Now opened the VM valve to slowly start collecting again once the still had sat on 78.5c for about 10 minutes, took about 200mls ant the temp jumped up over 80c again, turned the valve off, lowered the heat to just boiling very lightly, waited until she got back down to 78.5c then opened the valve again for about another 200mls before temp went stupid again.

Well ok fuck this mucking around after about 2hrs I've collected 400mls of heads, so shut all the valves, moved parrot back to LM and gave it half hour again to stabilize.
Cracked open the needle valve and started collecting again at about 4 drips per second for 15 minutes then the temp spiked again, close valve, start again, and on and on this kept going.

Tried moving back to VM again and same thing, temp spiked after 5 minutes, close valve, stabilize for 10 minutes, try again..... nope! same again......

After fucking around for about 5 hours I got about 2 liters of 95% and turned it all off knowing there was probably another 2 liters in the keg, it was a 40 liter charge.

Either I'm missing something simple or my rig is a piece of shit, surely it cant be this much trouble to run it.

Any ideas or suggestions would be greatfully accepted.

Cheers.

[Ayay]

Try a little more heat to make sure there is lots of reflux going back down the column...the reflux has been cooled in the condenser and it will cool the column from the top down and stabilize it. Crazy, but more heat can lower the temp in the column!

If it happens again, open the valve fully and you may see only 2 or 3 drips/sec coming out, ie there's hardly any left for refluxing when you tap off 2 drips/sec.

[Austin Nichols]

Try a little more heat to make sure there is lots of reflux going back down the column...the reflux has been cooled in the condenser and it will cool the column from the top down and stabilize it. Crazy, but more heat can lower the temp in the column!

Thanks

I did try and adjust the heat a fair bit during the run, but only by very small adjustments.

I kept wanting to pump the heat into it but kept telling myself no, just be patient, I'll work it out, but never gave it a good gut full of gas.

My burner is huge so there's no probs throwing heat at it, but I could here the boiling stones rattle in the keg and the dripping of the reflux if I got close enough to burn my ears..... I'm deaf as a post tho so it's hard for me to know/judge exactly how hard it's boiling.

Cheers.
edit. at 78c to 79c I could get a good stream flowing via VM or LM but every time I opened a valve the temp spiked....
I've done a fair few of these washes and always pulled about 2.2 to 2.5 liters of 92% from a 25 liter wash on my shop still, so I know my wash is fine.

[Austin Nichols]

ok now I'm half drunk I understand it all I think.

Turn heat up to cool column, yup! ok, not sure why I never thought of that... it makes so much sense now.

HAHAHAHA gotta laugh at how frustrated I was getting, I knew it was something simple.

[rad14701]

You're on the right track, Austin Nichols... As Ayay pointed out, more heat induces more reflux and, in effect, reduces the column temperature... Too little reflux is far worse than too much... You can keep pushing more heat all the way up until your condenser can no longer knock down 100% of the vapor at 100% reflux and then back down a bit... That will provide you with a good reference point for what your still can handle and you can then adjust your take off rate from there, making sure the temperature stays constant...

You'll get there, just hang in there... And no sampling while distilling... Stay safe and have fun...

[LWTCS]

And no sampling while distilling...

You Sir are a Task Master.

[Austin Nichols]

Well todays run is going pretty good so far

More heat to keep cool, yeah it's working sweet.

Started off 200ml fores.
600ml heads
getting good hearts now at 2 liters and still going, sitting on 78.7c

Couldnt be happier.

Thanks again for all your advise and support

[LWTCS]

WTG Austin

[rad14701]

Nice to hear that you're having greater success with this run, Austin Nichols...

[Kentucky shinner]

rad helped me out mucho when I started using my first Boka rig.. pretty sharp tack I would say.
Like larry said way to go Austin

[Austin Nichols]

Just finished doing my cuts and ended up with about 3 liters of good hooch, about 1 liter of heads and about 2 liters of tails, all this was from 35 liters of wash and about 5 liters of feints from previous runs on my other rig.

It's a bit early in the day for a drink so I'll wait till this arvo for taste testing, but every jar I pulled was 95% @ 20c until late tails, for a total run time of 7 hours from start up to turning gas off.

Best results I've ever had.

Cheers.