# Custom CNC False Bottom



## idzy (15/2/14)

Hi Guys,

I am beginning to do research on replacing my current 30cm false bottom. The reason being that I am not getting as great efficiency as I would hope for and a friend offered for me to do provide a design and he can make one with his CNC machine.

Main features I need to determine are steel thickness and hole size. Not sure if anyone has any ideas on this, but I was thinking 1mm and 1mm for these. The false bottom will be going into a Robinox Forje 70L Stainless Steel pot. Where I see potential efficiency gains is that the false bottom will go all the way to the sides of the pot, hopefully encouraging good vertical flow all the way to the sides. I have nothing to support this theory other than the designs I have seen on other systems.

The difference between 30cm and 43cm in area is 706 vs 1452, so it will have double the potential in theory.

Will post with more updates.


----------



## dicko (15/2/14)

I am not entirely familiar with the complete cnc process but your theory of making the false bottom fit all the way to the edge of the mash tun is sound and should ensure good extraction.
I will leave it to others to comment on hole size and spacing.


----------



## Smokomark (15/2/14)

Won't a full width false bottom potentially reduce your efficiency. The wort will take the path of least resistance and travel straight down the sides of the pot.

Have a read up before you commit to your design. Palmers How
to Brew has a bit of info on this.


----------



## dicko (15/2/14)

smokomark said:


> Won't a full width false bottom potentially reduce your efficiency. The wort will take the path of least resistance and travel straight down the sides of the pot.
> Have a read up before you commit to your design. Palmers How
> to Brew has a bit of info on this.


I think the path of least resistance in the Palmer book may relate to a manifold rather than a false bottom.
If it was the case with a FB then a Braumeister would not give such good efficiency.

These are of course, only my thoughts

Cheers


----------



## MHB (15/2/14)

smokomark is spot on, have a read of Palmer before doing any design work.
If you have a domed 30 cm FB in the pot already, it isn't what is causing your problems. I would be looking at the rest of your processes first.
Mark


----------



## idzy (15/2/14)

MHB said:


> smokomark is spot on, have a read of Palmer before doing any design work.
> If you have a domed 30 cm FB in the pot already, it isn't what is causing your problems. I would be looking at the rest of your processes first.
> Mark


Any chance of some elaboration?


----------



## idzy (15/2/14)

For the design, I was thinking something like these:

http://www.homebrewing.org/assets/images/stainless_steel_PICO_style_keg_kettle_false_bottom_with_supports_in_keg_half.jpg

http://www.homebrewingguild.com/home-brewing-images//Blichmann-False-Bottom.jpg

http://i304.photobucket.com/albums/nn176/wilko138/IMG_1210.jpg

http://brew.is/blog/wp-content/uploads/2011/10/2011-10-29-10.09.11.jpg

http://www.cobbersbrewery.com/images/brauduino/top-perf-closeup2.jpg


----------



## Online Brewing Supplies (15/2/14)

Read Kunze book on malting and brewing technology, it has all you need to know about % of open face etc.
The info doesn't get ay better, most of the info on here is subjective.
Nev


----------



## The Village Idiot (15/2/14)

Cutting a keg tomorrow and am very interested in views on this subject. If channelling down the sides is an issue, as Palmer suggests, should a full width false bottom have an edge or an unperforated section around the edge to minimise the side wall channelling?


----------



## MHB (15/2/14)

Have you gone and read the relevant parts of Palmer's book? if so you should understand what I posted, if not do you expect me to spend a great wack of time typing the same information out so you can read it here rather than go and do a bit of basic research to improve your own brewery.
sorry if that sounds a bit harsh but frankly if you understand what you are building and why you will be a better brewer for it.

Nev - Kunze is holy writ, but unfortunately a bit on the expensive side for people not in the industry, tho a great investment for anyone who really wants to understand brewing, my copy is only a couple of years old and already looks very second-hand.

TVI - if you want to make an exceptional mash tun out of a keg, I would fit one of the smaller domed FB's that are widely available to the narrower type of keg, or the larger if its one of the wider type of keg. In either case I would make the outlet on the centre bottom and weld on a bit of all-thread so you can screw the FB down securely, makes it easy to stir without the bottom moving and you get a very good drain down.


----------



## The Village Idiot (15/2/14)

Thanks Mark, that's what I was getting my head around. Used to have a round cooler with domed bottom and the outlet on top. PITA to stir and kept moving the falsie. Toying with the idea of feeding the mash from the bottom like a BM. Early days and a few headaches to come.


----------



## idzy (17/2/14)

MHB said:


> Have you gone and read the relevant parts of Palmer's book? if so you should understand what I posted, if not do you expect me to spend a great wack of time typing the same information out so you can read it here rather than go and do a bit of basic research to improve your own brewery.
> sorry if that sounds a bit harsh but frankly if you understand what you are building and why you will be a better brewer for it.


Don't mean to sound harsh back at ya MHB, but naming a book such as Palmer's "How to Brew" with no reference to the section is really not all that helpful. I did try to find the relevent info you were referring to and stopped after reading some misc bits as well as Chapter 12 on Mash Efficiency. 

Thank you from providing the link to the info you were referring to, this is indeed very helpful, and saves you the wack of time typing. Muchos Gracious!

EDIT: Haven't read reference yet, but wonder about those other designs and how they work comparatively to my current design and also in light of the reference material.


----------



## idzy (17/2/14)

Gryphon Brewing said:


> Read Kunze book on malting and brewing technology, it has all you need to know about % of open face etc.
> The info doesn't get ay better, most of the info on here is subjective.
> Nev


Thanks Nev, will check it out. Always after tips on good books.


----------



## Online Brewing Supplies (17/2/14)

idzy said:


> Thanks Nev, will check it out. Always after tips on good books.


I dont like to by pass the author but there was a copy floating out there is cyber space a while back.
I did pay for my hard copy.
Nev


----------

