Author Topic: Mash tun efficiency bazooka screen vs false bottom  (Read 17156 times)

Offline tfrommer

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Mash tun efficiency bazooka screen vs false bottom
« on: September 11, 2014, 11:46:09 PM »
Hi smart brewers,
After one too many issues with the false bottom in my mash tun (converted Igloo cooler) I'm trying a bazooka screen. A couple of batches later and while no more stuck sparges my efficiency has taken a nosedive. Have others experienced lower efficiency with a "BS?" The non-physics major in me could make some fake hypothesis about there being less surface area for wort to pass through but that doesn't seem like a good conclusion.

thanks.
Tim F.
Seattle
Cascade Brewers Guild

Offline klickitat jim

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #1 on: September 12, 2014, 12:18:27 AM »
How much gap between the bottom of the bazooka and the floor of the cooler?

Offline Joe T

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #2 on: September 12, 2014, 09:20:48 AM »
Bazooka screens are great for batch sparging. Terrible for fly sparging.
If you have a copy of How to Brew by John Palmer, check out Appendix F.
« Last Edit: September 12, 2014, 09:47:06 AM by Joe T »

Offline wingnut

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #3 on: September 12, 2014, 11:10:46 AM »
John Palmers book "How To Brew" talks about this (great book and worth picking up... below is a pretty good take from his website)

http://www.howtobrew.com/section3/chapter17-2.html

Bazooka will result in a less efficient extract from the grain bed.  You are esssentially draining the sugers efficiently from a much smaller area compared to a false bottom.   With the bazooka the middle of your cooler is having the grain rinsed well, but the edges are not, and will have more residual sugars left in the grain since thw water flow through that section will be slower than the  flow of water through the grain on top of the bazooka.

Two options are to accept the reduced efficiency and adjust your recipe, or if you are getting less than 70%, switch to batch sparging instead of fly sparging.  (I consistently get 73 to 78pct efficency with a similar setup and batch sparging).

The other option is going back to the false bottom and really slowing the flow during your lautering.  That will keep the grain bed from compacting.   (Becaue your bazooka is pulling from a smaller area, it is creating less suction on your overall grain bed and not compacting the grain as much.) 

Good luck!
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Offline tfrommer

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #4 on: September 12, 2014, 06:18:46 PM »
Thanks for the replies. I do have Palmer's book and will read through the referenced pages tonight. Sounds like I was on the right track with my guess.
Tim F.
Seattle
Cascade Brewers Guild

Offline Tim Boyden

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #5 on: September 12, 2014, 06:23:45 PM »
Another option is to use a custom BIAB filter bag in the cooler. Even better, add recirculation to pump the wort from the drain back to the top of the grain bed continuously during the mash. Your efficiency will go way up. Example at this link, bottom of the page: http://www.biab-brewing.com/?page_id=11

BIAB or Brew in a bag, is an all grain brewing method that allows one to use less equipment - ideally you mash and boil in the same kettle by lifting out the grain bag before boil. As you get to larger brew volumes, lifting a heavy grain bag can be dangerous and cause injury. So some BIABers have gone to a two vessel system, sometimes using another pot, sometimes using a cooler, to do the mash in, but still use the filter bags in lieu of a false bottom, bazooka screen, or manifold.

I have an electric setup and do temperature mashes, so I have two kettles, both with electric elements, and I mash in one, boil in the other, and use a pump to do the recirculating mash and the wort transfer to the boil kettle.

Offline denny

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #6 on: September 12, 2014, 06:25:57 PM »
Thanks for the replies. I do have Palmer's book and will read through the referenced pages tonight. Sounds like I was on the right track with my guess.

If you're interested in batch sparging, you might want to skip John's book and look at www.dennybrew.com
Life begins at 60.....1.060, that is!

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Offline theDarkSide

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #7 on: September 12, 2014, 06:52:08 PM »
I use a BS in my blue Coleman cooler and haven't seen a drop in efficiency.  My efficiency seems to be right around 78%, which is fine with me.

I love it so much more than the water supply braid I had that would get crushed or would float off the bottom of the cooler.
Seacoast Homebrew Club - Portsmouth, NH
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Offline denny

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #8 on: September 12, 2014, 07:06:27 PM »
I've posted this before, but the braid to be using is Lasco brand (part number 10-0121 or 10-0321).  Just because another braid is bigger, fancier, or more expensive doesn't necessarily mean it will perform as well.  In 464 batches with that braid I have never had a stuck or slow runoff.
Life begins at 60.....1.060, that is!

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The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell

Offline tommymorris

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #9 on: September 12, 2014, 10:51:43 PM »
I used to use a bazooka screen when batch sparging. I switched to the stainless toilet braid (Denny's suggestion on dennybrew.com). I like the toilet braid better because vorlaufing goes much faster. With the toilet braid I vorlauf 4 cups and then drain. With the bazooka I was filling a 2 qt. pitcher twice before draining.

Note: I was less experienced then, so, part of the difference in vorlauf amounts could be attributed to being a noob.

Offline Stevie

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Re: Mash tun efficiency bazooka screen vs false bottom
« Reply #10 on: September 12, 2014, 10:55:25 PM »
I always vorlauf 2 qts, hose braid on 40 qt and bazooka on 70 qt. I do it out of habit I suppose.