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My 1.5" boka

PostPosted: Sat Feb 08, 2020 11:24 am
by tubbsy
No questions, just pretty happy with a run I'm doing now.

Stripping 5L of 35% low wines from a TPW today in my home made 1.5" boka. It's made from stainless steel exhaust tube and has 500mm of packed scrubbies. I've tried a few different things as packing, including copper mesh and lava rock, but this run is the best so far. Only a few hundred millimetres in, but the 100ml foreshots came out at just a smidge over 95% and my first jar of heads came out at 95.5. Pretty stoked! I'll be taking the rest in jars of 200-250ml.

I've got a couple cheap $5 Chinese temp sensors - one in the column under the top slant plate and another in the coolant outflow. Camera couldn't take a proper pic of it, but the top is the column at 76.1 and the bottoms coolant temp was 40.9.

The boiler is just a 10L stockpot. The column to lid connection needs a bit of work as it still leaks, hence the flour paste.

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 12:00 pm
by Professor Green
Hi Tubbsy,

Sounds like you're having a good run but I have some safety questions for you.

Do you know what grade stainless steal the boka made from - exhaust pipe may not necessarily be safe for distilling spirits.
How are you sealing that stock pot? I can see you have some heavy duty clamps to hold the lid down but what is the seal made from?
I can also see what looks like flour paste on the top of the lid, this isn't really such a good idea and you should look at fixing any leaks in a more permanent fashion.

I'm not trying to be an arse, just being concerned for your safety.

Cheers,
Prof. Green.

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 12:07 pm
by tubbsy
I'm not trying to be an arse, just being concerned for your safety.


No problems at all. I'm safety conscious as well. The exhaust pipe is 304 grade stainless steel. The lid seal is made from EPDM. The flour paste will not be needed once I get the new lid and ferrules I ordered a few days ago.

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 12:40 pm
by tubbsy
Ok, I do have a question now.

To get azeo the output is less than 500mL per hour. Is that a typical production rate for my size still?

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 3:04 pm
by scythe
Yeah pretty much, if you want to go faster while maintaining high ABV you need to increase diameter or height.

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 6:02 pm
by RC Al
To be honest im surprised that you can hit 95 with a half meter of any diameter of packing - have you looked at the temperature adjustment for your alcometer? if your product was at 40 degrees and showing 95, you only actually had 91%
alcoholmeter_correction_chart.xlsx

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 6:08 pm
by tubbsy
I didn't measure this time, but I did on the stripping run and the liebig was able to get the temp down to 23°C.

Re: My 1.5" boka

PostPosted: Sat Feb 08, 2020 6:10 pm
by tubbsy
My hydrometer set only cost around $10 off eBay though, so they may not be the most accurate.

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 5:10 pm
by Sam.
tubbsy wrote:My hydrometer set only cost around $10 off eBay though, so they may not be the most accurate.


Metho should give you 95 and water 0, good test for the old alcometer ;-)

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 9:27 pm
by tubbsy
Thanks Sam. Will have to get some method tomorrow :handgestures-thumbupleft:

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 9:30 pm
by bluc
Just a question . Why would you build a 1.5" boka instead of a 2 or better yet 3?

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 9:38 pm
by tubbsy
bluc wrote:Just a question . Why would you build a 1.5" boka instead of a 2 or better yet 3?


Already onto it. Realised after my first run that I should have gone bigger - so I did! This is my 3" boka going through it's cleaning run. It didnt leak so I've since insulated it, for performance but also to hide my rubbish stick welding :shhh:

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 9:40 pm
by bluc
Lmfao nailed it :handgestures-thumbupleft:

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 9:41 pm
by db1979
I don't envy you trying to control the needle valve all the way up there.

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 9:43 pm
by tubbsy
db1979 wrote:I don't envy you trying to control the needle valve all the way up there.


Yeah, I didn't think that through. Thinking of attaching a stepper motor to it to do it semi-remotely.

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 10:11 pm
by bluc
how much packing you got?

Re: My 1.5" boka

PostPosted: Fri Feb 14, 2020 10:17 pm
by tubbsy
It'll have 1.5m of lava rock. I was thinking stainless steel scrubbies, but it would be weird having to buy the amount I'd need to fill it. Given the height, I'll use them as is (20-30mm) first to see how they perform, then will look at crushing them smaller after.