A false bottom is the best way turn a Sanke Keg into a mash tun if you plan to fly sparge and if you're direct firing your mash tun, a full width false bottom is the best prevention from scorching your grain and wort.
This specific model, FB15HH, is meant to be used with a diptube installed in the sidewall of your keg. If you prefer to bottom drain your tun, it will not require a diputube so you would look at model FB15H which does NOT have a hole.
NEW! We also now include a perforated center support for no additional cost to you.
This is the same unit we include in our keg to mashtun conversion kits so if you're starting with a fresh keg and need everything, check out those kits.
If you're comparing to other offerings out there, here are the vital specs: we start with 16 gauge (that's about 1/16" thick and we don't know of anyone making them thicker than this) 304 Stainless Steel sheet that has 3/32" holes punched over the entire surface on 5/32" centers.
We use a total of 12" of piano hinge that is spot welded at 10-12 locations per hinge and are also made of 16 gauge 304 stainless for strength and corrosion resistance. The hinges are necessary because the top holes that are typically cut in kegs are about 12" diameter and a full 15" disk would otherwise not fit.
Please read: Getting a false bottom to fit nicely in the bottom of a keg and have it work in perfect harmony with a diptube is not difficult to do but it does require attention to detail and consideration of the instructions. Please read everything on this page before ordering.
The hole for the dip tube penetration is a "11/16" to accommodate our oversized 5/8" OD diptubes, no matter how low the bulkhead is installed. When the diptube is installed as low as possible, there is very little gap between the FB and Diptube. The hole is punched on the centerline split between the two halves, but is offset from center in the other direction by 3/16" to allow for up to 3/8" of diptube length adjustability simply by rotating the disk 180 degrees. The hole is trimmed with a thick SS washer that is spot welded to one half of the false bottom which provides added strength to the center where the hinge is interrupted.
The last thing we want to mention is that all units will have a 1/8" thick stainless D-ring welded on to act as a pull handle ease in handling when installing and removing the false bottom. Many competitor units use a much wider "gate pull" style handle and we simply think it is unnecessary and just serves as another obstruction to stirring the mash.
Note: The primary application is for 15.5 gallon, American Sanke-style Kegs, that measure approximately 15.75" diameter just above the area that transitions to the dished bottom. This false bottom will self-center at the area where it begins to curve into the dish. While it may fit into other keg styles such as the European 50L, Coors, or Hoff Stevens, we have not had the chance to test this.
The details below will suggest the need to trim the diptube in most cases. The two easiest ways to cut stainless tubing is a tubing cutter (Lowes/Home Depot) meant to cut copper tubing, etc or a hack saw with a fine tooth metal cutting blade. In the case of the hack saw, you'll want to clean up the sharp cut edges with a file or sanding block. Please be careful. The cut edge is really sharp.
Dip Tube Length Requirements:
If you're just buying the false bottom by itself without the dip tube, we assume you already have a diptube installed or plan to make one yourself. No problem, maybe. You'll need to make sure they will mate up. The centerpoint of the center hole will be between 7.44" and 7.81" from the sidewall of the keg where you'd install the bulkhead (depending on how you rotate the false bottom). It should be obvious that a diptube that is a little too long can be trimmed, but there is nothing you can do if it is too short. If you've purchased a thread-in style diptube from us in the past, check the measurement because the lengths were never as precise as required here.
Bulkhead Type Considerations:
When installing with the weldless bulkhead with integrated 5/8" diptube, the fit is most precise because we know exactly where the keg wall is going to hit the assembly. Even in this case, we er on the side of too long rather than too short and trimming the tube may still be necessary.
If you already have a coupling welded in and select that style of thread-in diptube, we now base the dip tube length on the assumption that your coupling has been installed flush with the inside of the keg. If your coupling is welded half way into the keg or even flush with the outside, you will likely need to trim the length as discussed above.
Dip Tube Height Requirements
The height of the dip tube is less critical than the length, but there are some things to consider. First, if the drop is too long given your bulkhead install location, the horizontal tube is not going to seat into the compression fitting straight. In extreme cases, the compression nut won't even be able to thread on to the fitting. The easiest way to test fit is to install the diptube without the false bottom in your way. You can fix a long tube by trimming a little off the bottom opening. We recommend taking off small slivers at a time (no more than a 1/4" at a time). Keep test fitting it until the horizontal tube is sticking relatively straight out of the compression fitting while the bottom is just touching the bottom dish of the keg.
Many people will like to cut it even shorter to keep the opening from bottoming out on the keg and stopping the flow. However, our recommended solution to preventing bottom-out is to cut the bottom of the tube at an angle. AFTER you have the height trimmed so that it nearly hits the bottom, remove it and cut a triangular piece off the end. Then turn the blade to the end and remove the 3/4 piece. Now you have a point on the tube that will touch the bottom of the keg, but a wide open area to flow the wort out.
Now it's time to test fit the false bottom. Fold at the hinge to get the false bottom into the top of your keg, then open it up with the hinged DOWN. Drop the diptube (with compression nut and nylon ferrule in place) into the hole and try to get the horizontal tube into the compression fitting. You can slide the false bottom back away from the bulkhead to clear the compression fitting. Rotate the false bottom and notice how the diptube will get closer and further away from the bulkhead fitting. Ideally, you want the diptube fully seated into the compression fitting while the false bottom is well centered in the keg and sitting nice and level. If the false bottom is being held too far away from the bulkhead to sit flat, even when the center hole is rotated furthest away, you will need to trim the horizontal side of the diptube. Again, trim VERY little off at a time. Try 1/8" sliver off the end and retry the fit. This may be a hassle, but once you get the diptube trimmed perfectly, your subsequent disassembly for cleaning will be painless.
Competitor Diptubes: If you've already purchased a diptube from a competitor, it is 99% certain to be 1/2" OD tubing. You may be able to use it if it meets the length requirements discussed above. Keep in mind it will fit loosely in the oversized hole we use in the false bottom, but you can easily fill the gap with a short (1" long or so) piece of silicone tubing pushed up on the diptube. Keep in mind the diptubes do not need a press fit into the hole. Grain husks create the filter bed and bridge over small gaps.
In case it is not obvious from above, the diptubes discussed above are NOT included in the price of the false bottom on this page. This can be found on the buklhead page. This false bottom should be compatible with ALL 5/8" OD tube diptubes that we offer including the integrated weldess bulkhead version and both thread-in units (both for welded and weldless bulkheads). See notes above to determine if your currently installed diptube will work.
We have attempted to be as thorough as possible in describing these units, their application and installation requirements but much of the end result is dependent on the user's ability to adjust the diptube as described. It's not rocket science, but it's slightly more challenging than installing an iPhone cover. If you have any questions or doubts before purchasing, or need any clarification before you start cutting your diptube, don't hesitate to contact us.
Last thoughts.. FALSE BOTTOM STRENGTH! You'll occasionally read about folks collapsing their false bottoms in spectacular fashion. This happens more frequently in flat bottom pots where the disc is only held up by a few legs and doesn't have the same support around the circumference like in the case of a keg. That isn't to say that you can't collapse our false bottoms, or any others from any other vendor. Given the principals of hydraulics, you can actually apply enough vacuum using a March or Chugger pump to put 1000 pounds on top of the false bottom if you plug up your runoff hard enough. We've sold hundreds of units so far and have only had one customer report a collapse. However, we know what piece of mind is worth to many people so we're now including a center support with all false bottoms for no extra charge. This piece of tubular perforated is 2" in diameter and 1.75" tall. When installed in the bottom recess of the keg, the false bottom will hover over by 1/8" as to not interfere with positioning. It will make contact and provide support as soon as any weight is applied.