$5.00 False Bottom Plan

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I just ordered mine the other day, right after a big price drop. I'm looking forward to getting rid of my bazooka screen, and maybe start fly sparging. Thanks dude!
 
I am looking to move into all grain so I have been researching building a false bottom and this thread is great. I do have a question. John Palmer says this in chapter 17 of how to brew, "Another extraction efficiency problem that needs to be considered when designing your tun is preferential flow down the walls. The smooth space between the grainbed and the wall of the tun can be the path of least resistance to the drain. To minimize this short circuiting, false bottoms should fit tightly". I am curious how some of these FBs are fairing in efficiency, in light of this preferential flow. Some of the pictures shown clearly show a false bottom smaller than the mash tun itself. I am very interested especially in the plastic microwave screen because it seemed the easiest to find/make and you don't have to worry about trying to find a stainless steel one. Did anyone make that plastic one and have problems with preferential flow or even the plastic colapsing under the weight of the grain?
 
I'm going to make one of these for my cooler I bought to make a mash tun with. Insted of the screen.
 
Hey Everyone,

I wanted to do my first all-grain brew and did a lot (A LOT) of research into to the best methods, costs involved, etc. I decided that the false bottom would give me the most flexibility, but at anywhere from $30-$100 for professionally made ones, my inner Scrooge said, "Bah, humbug!" So I did some more looking and came up with my own using only $5 worth of parts. It's for a 5 gallon Igloo beverage cooler, but the design is simple and could be modified for almost any size round mash tun. I'll admit I'm as green as one gets to brewing and would greatly appreciate any comments and suggestions about my design. It's still untested, but I'll be brewing a Scottish Heavy Ale next week and will post an update as to how it performed.

Parts List
(1) 9" 18-gauge Aluminum Pizza Pan; 0.4" depth - {I got mine from a restaurant supply store} - $2.88
(1) PEX Elbow Adapter; brass - {From Home Depot in the plumbing section} - $1.71
(2) #31 O-Rings - {Home Depot in the faucet repair section} - $0.23/ea
1/8" drill bit
1/2" or 3/8" drill bit - {Depending on your inlet size; I made my assembly out of 1/2" parts, so I used a 1/2" bit}
Variable speed drill
Ruler or T-Square
Pencil
Scotch Tape
Old cutting board or sheet of wood
Safety Glasses - {Better to look like a dork for an hour that a pirate the rest of your life :D}

How To
Begin by taping the pizza pan domed side up to the cutting board. This will make it easier for the rest of the steps. Use the ruler or T-Square to draw a straight line down the center of the pan. Rotate it 90 degrees and make another line so the cross marks the center of the pan. Mark the lines every 1/2" from the center out to the edges on each axis. Finally draw parallel lines at each mark to form a grid:

Put on your goggles and start drilling 1/8" holes at each point on the grid. There'll be about 250 of them so it'll take a while.

When that's done, use the 1/2" or 3/8" bit to drill the port in the center of the pan for the PEX elbow. Use a wire brush, sandpaper or the like to clean all the barbs off the underside of the pan from drilling. Wash the pencil grid of the pan and use a garden hose or high pressure water to clean off any metal flakes that may have collected in the rolled rim of the pan.

Take one of the O-Rings and push it onto the inlet side of the PEX elbow about halfway down the barb. Insert the elbow into the port in the center of the pan so it looks like this:

Holding it in place, take the other O-Ring and push it over the inlet barb on the underside of the pan. The PEX elbow should be held firmly in place, decently sealed and easily rotated:

Here's mine installed in my mash tun. I used 3" of 1/2" braided tubing to hold mine in place and it is held snugly. You could also use copper tubing with compression fittings, but I find this way much easier to deal with as far as installation and cleaning are concerned.

I put 1 gallon of water into the tun to test dead space and it was only 1/4 gallon short, so not too bad. Hopefully some of you can mess around with the design and I'll post my findings when I brew next week.

NOTE
11/16/2012 -- A few people have mentioned that due to the lightness of aluminum there have some issues with the false bottoms floating while mashing, causing stuck sparges by grist getting caught in the dip-tubes and lines. One way to remedy this is to use rigid, braided food-safe tubing from the PEX elbow to the barb on the valve. This is what I use and I haven't had an issue with floating or stuck sparges.

Another would be to use compression fittings and copper/SS tubing which would keep the false bottom in place as well. This is what I'll likely use when I upgrade to a 10 gallon mash tun in the future.

Finally, adding weights to the false bottom such as SS washers above and below the PEX elbow or weights mounted along the upper edge of the rim would likely cure this issue as well.

Update

I brewed with this false bottom for the first time today and I’m honestly impressed at how well it worked! Hit 85% efficiency and had only a pinch of grain material come out while fly sparging. The tun had a fast, steady flow and didn’t even hint at a slow or stuck sparge. Had exactly 5.7 gallons of wort which was what BeerSmith predicted.

Even though this is my first all-grain brew, this false bottom worked much better than my friend’s who uses the braided S/S line method. She often has to fiddle with it and complains of stuck sparges all the time. Cheap B-Day present, perhaps? :D

I got the hole size and spacing parameters from a fantastic article I read by John J. Palmer and Paul Prozinski here: http://morebeer.com/brewingtechniques/library/backissues/issue3.4/palmer.html. It has some great info on improving mash efficiency and it taught me quite a bit.

UPDATE
12/3/2012 - I upgraded to a 10 gallon Igloo cooler for my mash tun to do higher gravity brews and made a new false bottom. This one is made from a 12" stainless steel pizza pan I purchased from Amazon for $13. I cannibalized the parts from my 5 gallon mash tun and they work flawlessly. Here you can see the the false bottom made with the same 1/8" drilled holes at 1/2" offsets. I set the PEX pickup end as low as possible under the false bottom as this pan is a bit deeper than the 9" in the previous build. Hopefully this will minimize the wort lost to dead space. I'm planning an Imperial IPA next and will report the new mash tun's performance once it is complete.

UPDATE

12/29/2012: Brewed an Imperial IPA with the new 10 gal mash tun and 12" pizza pan false bottom. Worked even better than the original 9" version. The addition of S/S hose clamps on the dip tube made grain material in the 8qt re-circulation almost non-existent so I highly recommend using them with this design. Hit 82% efficiency and there was no hint of a stuck sparge (very smooth, slow, steady flow). I'm very happy that a second iteration of this design has proven as effective as the original.

I know what I'm doing this weekend. Great diy build, thanks for posting
 
I am looking to move into all grain so I have been researching building a false bottom and this thread is great. I do have a question. John Palmer says this in chapter 17 of how to brew, "Another extraction efficiency problem that needs to be considered when designing your tun is preferential flow down the walls. The smooth space between the grainbed and the wall of the tun can be the path of least resistance to the drain. To minimize this short circuiting, false bottoms should fit tightly". I am curious how some of these FBs are fairing in efficiency, in light of this preferential flow. Some of the pictures shown clearly show a false bottom smaller than the mash tun itself. I am very interested especially in the plastic microwave screen because it seemed the easiest to find/make and you don't have to worry about trying to find a stainless steel one. Did anyone make that plastic one and have problems with preferential flow or even the plastic colapsing under the weight of the grain?

The false bottom on this will fit tightly, the weight of the plate itself will keep it down if its Stainless Steel. Some people posted previously about the aluminum one floating, and ive read other threads with people using plastic and it floating too. Ur better off going with SS as that won't bend in the middle under the pressure of heavy grain bills like the plastic one could. Plus with high temps, plastic becomes more pliable so i think thats even more recipe for something to go wrong.
 
I am looking to move into all grain so I have been researching building a false bottom and this thread is great. I do have a question. John Palmer says this in chapter 17 of how to brew, "Another extraction efficiency problem that needs to be considered when designing your tun is preferential flow down the walls. The smooth space between the grainbed and the wall of the tun can be the path of least resistance to the drain. To minimize this short circuiting, false bottoms should fit tightly". I am curious how some of these FBs are fairing in efficiency, in light of this preferential flow. Some of the pictures shown clearly show a false bottom smaller than the mash tun itself. I am very interested especially in the plastic microwave screen because it seemed the easiest to find/make and you don't have to worry about trying to find a stainless steel one. Did anyone make that plastic one and have problems with preferential flow or even the plastic colapsing under the weight of the grain?


I usually hit 80%+ efficiency with my SS one and haven't had any issues as far as channeling is concerned. In my Igloo cooler, at least, the pan fits snugly under the barb adapter inside the mash tun and with the threaded tubing and weight of the mash it holds down well. When draining the wort I always run it through a mesh strainer to catch any bits that may have gotten through and I never have more than a pinch or two of grist.

One modification that I have played with and would alleviate any concern regarding the false bottom floating up, but that I haven't gotten around to doing on mine, is to use a SS dip tube with compression fittings angled slightly to keep the whole thing rigid and tight.

I don't have any experience with the plastic screens that some have used, but as long as you put some support feet on it between the false bottom and the bottom of the cooler I imagine it wouldn't have any issues flexing under the wort temp/grist weight, but I have no idea if floating would still be problematic.
 
... Did anyone make that plastic one and have problems with preferential flow or even the plastic collapsing under the weight of the grain?

I built the plastic false bottom on my first all grain system in an effort to save money. It worked good. However I did have a couple of problems that needed work arounds.

1) To keep it from collapsing and stopping flow I used the largest 90 deg elbow I could find and then put notches in the portion that protruded through the bottom (see picture).

2) It did eventually loose it's original shape due to the heat and weight of the grain. To compensate for this and potential lifting I would put a 1 gal strainer bag that I bought at Lowes over the entire false bottom. This would prevent a stuck mash by keeping grain from potentially getting under the false bottom.

I believe it is safe to say that "every" false bottom that just sits on the bottom of the mash tun has the potential to lift and allow grain to get under it. I have friends who have had this problem with stainless steel ones they purchased online or from their homebrew shop.

I got great efficiency with this false bottom but to be honest it was just a cheap way for me to start doing all-grain without spending a lot of money. I have since moved on. I hope you enjoy your journey as much as I have! :-D

Thom

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Yeah that one looks awesome and you cant beat that price. I think I paid 14 bucks for the one previously linked. Love how amazon jacks around with its prices based on page views...
 
Yeah that one looks awesome and you cant beat that price. I think I paid 14 bucks for the one previously linked. Love how amazon jacks around with its prices based on page views...

Yeah when I first looked for one after finding this link the pan was $13 and change. I checked a few days later and it dropped to less then $8.

If ur patient u can def save urself a few bucks.
 
To give you an idea, I'm brewing a chocolate oatmeal stout today. Here is a picture of how much grain got through in the sparge from a 12.5# bill. It was composed of mostly particulate matter. Not too bad:

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The only thing I hesitant about is how flimsy the $6 is compared to the $20 one :/ still haven't pulled the trigger.
 
Unless it's like one of those disposable foil turkey pans you use at Thanksgiving I imagine it will work fine. You can always make some brass, copper or SS "feet" for it (something similar to these, for example), say 3 or 4 around the dip tube pickup to support it and you'd still come out ahead price wise.

A few places to check out are restaurant supply stores near you or one of those kitchen gadget stores that pop up in malls. At least then you could hold it and see if it is too thin to hold up to 15# grain bills.
 
Has anyone had the problem of grain getting under the pizza pan? I had a serious stuck sparge this weekend. I had to empty the mash tun and found that my pizza pan had lifted up. Did I just stir to vigorously or what?
 
Has anyone had the problem of grain getting under the pizza pan? I had a serious stuck sparge this weekend. I had to empty the mash tun and found that my pizza pan had lifted up. Did I just stir to vigorously or what?

Check back on the first page. The aluminum ones are light and had this problem. Adding SS washers to it can help keep it weighted down.
 
Has anyone had the problem of grain getting under the pizza pan? I had a serious stuck sparge this weekend. I had to empty the mash tun and found that my pizza pan had lifted up. Did I just stir to vigorously or what?

One thing that has helped with mine is to cut the braided tubing a little long (maybe 1/4" - 1/2" longer than what you need) so that it creates a bow in the tubing (with the apex of the curve facing the cooler opening) that pushes the pan down a bit. The pan will be slightly off center, but should still make complete contact with the cooler's bottom. If it doesn't, just shave a bit off the end and refit it until it does. Afterwards, add some mash temp water that just covers the braided dip tube and leave it sealed for about an hour. Drain it and pour some cold water on it. It should retain that curved shape for future mashes.

I never had a stuck sparge, but was having more grist come out during the sparge than was ideal until I did that when I was using the 9" aluminum pan. I did the same with my 12" SS and, as you can see from the picture above, grain coming from the sparge is almost nonexistent.

The other thing that you should be careful of is not to catch the dip tube with your paddle or spoon when stirring, since you mentioned stirring vigorously. I've caught myself once or twice almost doing the same thing while mashing. If I'm trying to get to the stuff on the bottom of the grain bed, I'll stir the grain parallel to the dip tube (which you can find easily by looking at where your valve is) to avoid hitting it.

I imagine if I were to upgrade to compression fittings and a SS dip tube none of the above issues/work-arounds would be necessary, but I'm just too lazy at this point to go to the trouble, ha ha.
 
Great thanks for the advice. I'm using high temp silicone tubing so I can mold my tubing. But I'll probably cut a longer length that way it will push the pan to the edge of the cooler.
 
I was using a CPVC solution with slots cut into it with my bandsaw but had some nasty stuck sparges in the last several brews. I vowed I was done with it. Looked online and decided to gamble with a cheap colander from amazon. http://www.amazon.com/gp/product/B0096C9220/?tag=skimlinks_replacement-20

You can see in the pictures that I just cut a hole in the side of the colander with my dremel and fit my CPVC solution underneath. Sort of a back-up to the colander, but after pulling it out, I don't think any grains actually got past the colander to the CPVC - but doesn't hurt to have the back-up in there so will probably just keep using it.

It worked fantastic. A little higher dome than some other solutions, but that doesn't affect the dead space, just recirculate as usual. Was able to easily stir the mash around it. Fits snuggly into my 10gallon HD cooler so overall am very very happy with my $11 purchase. And no drilling needed which was a bonus.

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Thanks for the idea. 366 7/64" holes with a $1 bit (and a bit of cutting oil), angle grinder (with sanding/carving disk) to smooth the back side. Used a $11 (12.75" ) pan over the $8 (13.5") pan because it's lip looked better for the side mounted pickup tube.

It has been mentioned before, but if I do it again I would mount a sacrificial backing to the pan. The burrs from previous holes caused the pan to stand off the floating backing, increasing the burrs. The longer burrs also cause the holes to dent a little.

I used a greenlee 13/16" punch for the pickup hole. It is a little over-sized for the barbed 90 elbow fitting (used a "True Bulkhead" fitting from brewhardware), but the extra room helps to make the bottom removable and I expect a silicone washer will keep any grain out
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