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problems scaling up size

Posted: Wed Dec 10, 2008 10:08 pm
by eternalfrost
well i have been distilling about 6 months now. i started on a 20L stockpot i ran off my kitchen stove. i stocked it with a standard 5 gallon beer fermenter bucket. usually would do 2 runs off each ferment.

over the past few months i have been upgrading into a bigger setup once i got the hang of things. i have the same column as before but now it is on a electric keg boiler. i have also beefed up my fermenter to a 30 gallon barrel to handle the new keg.

i have just finished my first 100% run on the new setup and am very disappointed. i used to get around 93% ABV off my column with the stockpot setup. now i can barely hit 88%... i am using basically the same procedure, 2 or 3 full blast stripping runs then combining, watering down to ~40% and doing a slower spirit run. i fiddled around with the take off rate and the heat input throughout the run but nothing seemed to make the meter drop.

im just wondering if anyone with experience with bigger rigs can toss me some input. i tried heat inputs from about 1500W to 750W and take off rates from around 2 drips per second to a pencil lead size stream. nothing i did got it above 90% and the average was around 88%

im just pretty disappointed because the final product from the new rig is much worse then my previous set up. i dont know if its just needing to learn how to 'drive' it better with more practice or if there is some underlying problem in the fermenting/distilling side.

any input would be welcome...feeling pretty dejected at the moment :roll:

Re: problems scaling up size

Posted: Wed Dec 10, 2008 11:25 pm
by Hawke
The boiler size should not have any effect on the column. If 1000 watts drove it on a 20lt pot, should run it on a 50lt pot, just take longer to get to temp.

Re: problems scaling up size

Posted: Thu Dec 11, 2008 10:22 am
by punkin
As far as the % goes, got nothing further for ya than what Hawke said, aside from modifications (column extension) to get ya up to 95+%. As far as the flavour, it might take a while to settle into a new patina on your boiler and adjusted column joints.



What is your packing, and has it changed at all (put in looser or something)

Re: problems scaling up size

Posted: Thu Dec 11, 2008 2:57 pm
by eternalfrost
nothing has changed except the boiler and method of heating. im stumped, dosent make sense. guess ill just have to keep messing around with her.

been thinking of adding another foot or two of height and switching to a VM head anyways. sick of fiddling with that damn needle valve :evil:

Re: problems scaling up size

Posted: Fri Dec 12, 2008 9:27 pm
by Freedave
i'll second what punkin said bout breaking in the boiler.

think that was part of my problem. even though it's stainless steel it still may need to be broken in. maybe

oh yea, but that doesn't explain the 4% drop in abv. nevermind.

Re: problems scaling up size

Posted: Sun Dec 21, 2008 12:03 am
by eternalfrost
one thing i noticed on my last run was the threaded connection to the keg was leaking a bit. nothing liquid but enough to smell when you put your nose in it. was half way through the run and tied a rag around it, was a slightly damp by the time it was done...

after everything cooled off i found out that the threads had gotten all gunked up with dried backset etc.
dont know it that would have anything to do with the poor results on the new boiler...

plan on replacing the whole connection set up when i find some pipe to extend the column. its a major pain in the ass tightening it down with the club-sized wrench and sealing it all the time. will just use the DIY tri-clamp method from the 'super scotch' thread

Re: problems scaling up size

Posted: Thu Feb 05, 2009 5:09 pm
by aleksandr1
if you scaling up the boiler only then you have to keep in mind that by increasing the surface area of the boiler you will loose some heat to the surrounding environment, first just heat insulate your boiler and increase a little the heat production by replacing the heating element, if you scaling up the column and leaving the old small element then you should know that there is not enough of vapor produced to for the correct reflux ratio and columns filling is stays dry and water from the boiler is reaching the top of tower (high temperature at the top of column, low percentage of spirit) you should either reduce the spirit flow speed during collection (if your still is controllable) or again use more powerful element.the rule is if you apply 1kw of power to the still you should take no more than one liter of 95%+ spirit per hour the rest is your reflux just do not be greedy, and so on - 2kw = 2L per hour...and so on or if you do not know the element rating just let your still to work without the reflux ratio control and calculate the amount of spirit produced per minute, then divide the result by four and adjust your still to utilize 3/4 of the spirit total per minute and collect only 1/4 of the total per minute. I personally use the fractional still that I've build myself, I get plans from http://www.ferromit.com" onclick="window.open(this.href);return false;" rel="nofollow and this still is easier to build and use than the VM-ARC still. :D

Re: problems scaling up size

Posted: Fri Feb 06, 2009 1:42 am
by VicBill
One thing i noticed on my last run was the threaded connection to the keg was leaking a bit. nothing liquid but enough to smell when you put your nose in it. was half way through the run and tied a rag around it, was a slightly damp by the time it was done...
I have that exact problem. Just chuck some flour paste all the way around the joint (outside). Problem solved. Flour paste is marvelous.