Using a smaller false bottom (diameter) in larger kettle?

microbusbrewery said:

You could see a slight change in efficiency, but it's negligible IME. I used to have a round cooler-based mash tun. I switched to a stainless pot mash tun and use the same FB that I used in the cooler. The pot is almost 16"in diameter. When I switched I monitored my efficiency very closely and didn't find a detectable difference (both vessels yielded between 82 and 85%).

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Bobby_M said:

If you plan to put a flame under it you want to keep all the thick mash off the heating surface. Other than that, a full diameter fb won't move around as much.

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thehopbandit said:

What are the downsides, if any, of using a smaller false bottom in a larger mash tun / kettle?

My stainless mash tun will be roughly 15-15.5" in diameter. I understand that using the largest fitting false bottom is preferable, but I have found some pretty great prices on some stainless steel domed 12" false bottoms. I am wondering if this will work ok given the diameter difference and the excess space?

Are there any downsides? Any considerations with something like this? Anyone have a similar setup?

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cantrell00 said:

Not at all. I have the exact setup that you describe.

Use a rigid piece of pipe and I would use the FB sold at adventures in homebrewing too.

Here is mine. Couplings are soldered in.

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cantrell00 said:

$85 polarware economy 42 qt, 10.5 gallon

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thehopbandit said:

Do you ever use direct flame on the mash tun to regulate the temp? If so, any issues with the malt getting scorched due to the thin bottom?

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tsl346 said:

I would be careful about how fast you sparge. The larger surface area you have the more spread out the grains will be and the slower the water will flow through each square inch. If you have a smaller false bottom and plan to sparge relatively quickly you will have more flow through each square inch and have a higher likelihood of a stuck sparge.

I do 5 gallon batches with roughly 12 lbs of grains and my sparge takes approximately 50 minutes through a 12" false bottom. If you are doing a 10 gallon batch (assuming with your 15.5" dia pot) with 24lbs of grains still through a 12" false bottom then to do a 50 min sparge there will twice the amount of water going through the false bottom and a higher likelihood of a stuck sparge.

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thehopbandit said:

What size is your kettle? If it's larger, any issues with using the smaller false bottom?

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