80% from a Bokakob inline?

CoopsOz · Post by **CoopsOz** » Fri Sep 22, 2006 9:14 pm

G'day....I ran a 23 litre wash at 18% (with the addition of tails) last night. It was distilled with a 1.3KW element, my cooling water never got hot and it took about 4hrs from go to whoa. But, I only got 80%....did I run the damn thing too fast, is my column overpacked (SS scrubbers) or not packed enough....there is 15 scrubbers in the 1.1m column (43"). What did I do wrong? I took 1L of heads, 1.2L of mids and about a litre of tails. That's 4.2 litres, by my calcs...that is correct.

Anyway.....I know you are gonna send me off to read the parent site, so here I go again

nanosleep · Post by **nanosleep** » Fri Sep 22, 2006 9:46 pm

Sounds like it may have been a little fast. Do you have a thermometer in the head? I usually slow down collection until the temp lowers, then I use smell to determine my take off rate. I usually do my 25 liter fermenter in two runs of 3 or 4 hours each. A 1.1 meter column should do better than 80%. I don't remember how many scrubbers I put in my column. It's something like one scrubber every 5 cm. Your 15 scrubbers in 1.1 meters (one per 7 cm) seems reasonable. Slow down the collect rate and see if the purity improves.

CoopsOz · Post by **CoopsOz** » Fri Sep 22, 2006 10:41 pm

I do have a thermometer, although it is a classic case of "you get what you pay for", I tested it on boiling water and it only read 98C. Plus, even though the column is insulated, my thermometer was continuously fluctuating. It's high time I spent the cash to get a decent one.

rkr · Post by **rkr** » Sat Sep 23, 2006 12:24 am

To distill 25 liters of 15% mash to 3.5 liters of 95.6% stuff with my E-ARC takes roughly 8 hours using 1kW. Now this system keeps the reflux ratio optimal all the time which regular user with an LM still is unable to achieve. Based on this I'd say your run should take 10-14 hours if you plan on getting pure 95.6% stuff.

Cheers, Riku

hornedrhodent · Post by **hornedrhodent** » Sat Sep 23, 2006 3:02 am

Looks like you did a stripping run.

pothead · Post by **pothead** » Sat Sep 23, 2006 5:44 am

hornedrhodent wrote:Looks like you did a stripping run.

ya took the words out of my mouth.

CoopsOz · Post by **CoopsOz** » Sun Sep 24, 2006 2:49 am

OK...so it's official, it was a stripping run. Kinda futile as I have two elements that need at least 5L of liquid to cover them. In order to redistill I've gotta add more water.....I'll slow it right down this time!

pothead · Post by **pothead** » Sun Sep 24, 2006 3:52 pm

I'd do more strippin runs instead of adding tons of water

CoopsOz · Post by **CoopsOz** » Sun Sep 24, 2006 6:21 pm

What is your suggestion....just put the 80% stuff to the side, do another wash and subsequent stripping run, and then throw it all in together to make the proper cuts? It seem's like alot of work when others are getting 90% plus from a single run.

DBM · Post by **DBM** » Sun Sep 24, 2006 6:30 pm

Unless your 80% has something wrong with it (off smell or bad taste). Why not dilute it down to 100 proof and drink it ?

duds2u · Post by **duds2u** » Mon Sep 25, 2006 1:40 am

Sounds like your still design is very similar to mine. same element but my column is only 1 metre. Yairs, I do get 95% out of it and my suggestion is patience, patience, patience. Slow your collection rate and you will be right up there at 95%. It's amazing what happens in an extra hour.
Cheers
Duds

nanosleep · Post by **nanosleep** » Mon Sep 25, 2006 9:11 pm

I do have a thermometer, although it is a classic case of "you get what you pay for", I tested it on boiling water and it only read 98C. Plus, even though the column is insulated, my thermometer was continuously fluctuating. It's high time I spent the cash to get a decent one.

What is your altitude? From a quick google I found that at 2000ft altitude water boils at 208.4F. If I did the math correctly this is 98C. Your thermometer may be absolutely correct.

If the head temperature was high (but stable) during your run I would say you aren't providing enough reflux. Since it's flucutating, it sounds more like you may be flooding the column. What diameter is your column? How much temperature swing are you seeing?

You can pour in enough water to cover your elements, then pour in the stripped alcohol. There's nothing wrong with doing this. The reason most people don't is that you do two runs and spend double the time. I do quick stripping runs when I don't have time to invest in a long high quality run. Once the alcohol is stripped there's no problems with aging or bacterial infections.

duds2u · Post by **duds2u** » Tue Sep 26, 2006 2:43 am

Rereading your post about your thermometer temp fluctuating. I think that your thermometer probe may have condensate falling onto it. Make sure that the end of the thermometer probe is measuring vapour temp only and not having any liquid falling onto it..
Cheers
Duds

markx · Post by **markx** » Wed Sep 27, 2006 1:02 am

Liquid pouring over the temp probe may cause fluctuations in certain cases but in my setup the temp is rock solid even though all the refluxing liquid falls directly over the thermometer probe. Temp fluctuations arise when you don't provide enough reflux to equalize the column (like in the case of a stripping run when you operate with valves wide open) or when you flood your column by providing too much heat input. So I think that you just need to take it slower and let everything stablise nicely before you take anything out. A 1.1m column packed with 15 scrubbers should handle 95% with ease.

CoopsOz · Post by **CoopsOz** » Fri Oct 06, 2006 3:27 pm

Just a follow up. I've changed the rig, replaced the ball valve with a needle valve, (I know, like everyone said in the first place, I was trying to do it on the cheap and ended up spending more). Replaced th SS scrubbers with copper structured mesh and ran it a slower. I only got 87%....but at least it's an improvement. Another 6 or 7% and I'll be happy!

rkr · Post by **rkr** » Fri Oct 06, 2006 11:23 pm

CoopsOz wrote:Just a follow up. I've changed the rig, replaced the ball valve with a needle valve, (I know, like everyone said in the first place, I was trying to do it on the cheap and ended up spending more). Replaced th SS scrubbers with copper structured mesh and ran it a slower. I only got 87%....but at least it's an improvement. Another 6 or 7% and I'll be happy!

Huh, you are definately doing something wrong or there's some fault in your rig. I had an EL still loosely based on Alex's design and it was very easy to get 95.6% stuff using ballvalve for controll and scrubbers for filling.

Things to check:
Reflux is returned to the top of the packing and in the horizontal middle of the column?

You did let the column equilibrate for at least 30 minutes, preferrably an hour or two?

You were taking the stuff out slowly enough?

Cheers, Riku

pothead · Post by **pothead** » Sat Oct 07, 2006 3:08 am

Personaly, I think your heating element is a little too powerful for that size wash. I use a smaller one than that with 13 gallons in a keg.
I found I get the highest proof when I use about 750(or so) watts. I use a larger 240v element plugged into 110v.
I think the vapor traveling slowly up is what helps the most.
taking the product off REAL slow helps too.