I've upgraded from a 20L homebrew system to a 200L system and used it for the first time the other day. I previously did boil-in-the-bag but for my new system I have a false bottom. For my first test I decided to try a half-batch. The problem was that several kilos of grain managed to get down beneath the false bottom, blocking the outlet and also clogging the pump with grain, preventing me from being about to recirculate or transfer to the boil kettle.

I've been thinking about what could have gone wrong and the possible solutions: - maybe I need a full batch so that there's enough grain weight to compact the grain bed above the false bottom so that the grain at the bottom doesn't fall through the holes or the small gaps around the side - maybe I turned on the pump before the grain had chance to settle which created a vacuum and sucked the grain down through the false bottom - maybe I knocked the false bottom when doughing in

I'm thinking of putting a roll of muslin cloth around the edge of the false bottom to get a better seal against the edge of the tun. Maybe also put a layer of muslin cloth over the false bottom itself to provide an extra layer of filtering. Another idea is to put a steel scourer (like for scouring dishes) in the tun outlet to filter out more grain - I'm worried though that it will still clog up the outlet and restrict flow to the point that my self-priming magnetic-drive pump won't work or might cavitate...

Any suggestions or ideas would be greatly appreciated. Thanks!

  • So in the end I put a couple of those steel wire thingies for scrubbing dishes in the outlets and also sewed some muslin cloth around the edge of the false bottom. Not a single grain came out! Wasn't too difficult to clean either. Now on to the temperature control issues :p image1 image2
    – Snowman
    Commented Dec 2, 2014 at 13:12
  • Out of curiosity, will you brew commercially with that? Or are you really, really thirsty? Commented Dec 4, 2014 at 20:58
  • @CleberGoncalves A bit of both. A keg for me, a few for the bar. :)
    – Snowman
    Commented Dec 5, 2014 at 3:10

2 Answers 2


I think you have the right idea about sealing the rim of your false bottom. The common method is to use a length of vinyl tubing slit lengthwise. The false bottom fits into the slit as you wrap the tubing around it.

  • On a 200L system??
    – brewchez
    Commented Dec 1, 2014 at 20:08
  • Sure, why not? What would the problem be?
    – Denny Conn
    Commented Dec 1, 2014 at 20:53

200L? Wow.

You might consider using a length of copper tubing with slits cut in it, instead of a false bottom. My mash tun came with a false bottom which was always a bit of a pain to get nicely into place. One day I replaced it with the copper tube thing and I love it! I have since replaced my mash tun with a larger one, but I'm still using the same copper tube.

You can find lots of pictures of these online, but most are manifolds built from sections of straight tube and elbow joints. That's cool, but I think mine was simpler to make. I just used a single piece (about 2 - 3 feet) of flexible copper tubing. I put masking tape over one end, and filled it with salt. (Sand would work too, if you have access to sand.) Then I bent it into a coil. The salt inside is essential to prevent it from kinking. After it had the right shape, I just used a hacksaw to cut slits in it every 1 or 2 inches. Pinch one end closed, and put the other into the outlet on your mash tun.

I really love this simple solution. And you hardly need to do any vorlaufing at all. The only time it clogged is once when I put the grains in first, and then the water on top. Now I just always start with the water, and then stir in the grains, and it works like a dream!

Here's what mine looks like, shown from the bottom. (You put it in the mash tun with the slits down.) copper tubing with slits for mash tun

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