Grain bed depth

I'm currently mashing in a 5gal Igloo with a grain bag. My first AG used 12# of grain and was really pushing the capacity of said cooler.

So over the weekend I saw a 50qt cube cooler at Target for $20 and nabbed it. I figure that'll be good for big 5 gallon recipes or normal gravity 10 gallons. It's 13"x13" inside.

I'm planning to build a false bottom or manifold for it. The thing I'm wondering is if there are any resources to determine how much grain you'd need to make a deep enough grain bed for good filtering.

The reason is I'm wondering if I should keep my 5 gallon MLT for smaller beers in order to get an acceptable bed depth.

In the 13"x13" square cooler, 1 gallon of liquid is 1 3/8" deep. In the round one (assuming 9" round) it's 3 5/8. So the grain bed would be twice as deep in the 5 gallon for the same amount of grain.

-Joe

If you're batch sparging, it makes no difference at all.

Eh? Then what's the point of vorlaufing to get clear runnings? Won't a shallow grain bed prevent this from doing any good?

-Joe

The bed doesn't have to be that thick to filter during vorlauf. You'll have a few inches minimum on just about any recipe. I've done 3.5% beers in my keg based mashtun and it clears up quickly with a shallow bed. You'll be happy with the 50qt.

nostalgia said:

I'm planning to build a false bottom or manifold for it.

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Just curious, have you considered using a braid?

wilserbrewer said:

Just curious, have you considered using a braid?

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I have, and that will be my fallback option if the FB or manifold don't work out. I have a feeling I'd end up destroying the braid pretty quickly. I play rough apparently

-Joe

Bobby_M said:

The bed doesn't have to be that thick to filter during vorlauf. You'll have a few inches minimum on just about any recipe. I've done 3.5% beers in my keg based mashtun and it clears up quickly with a shallow bed. You'll be happy with the 50qt.

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Thanks for the info. Right now I mash in a big nylon mesh bag, but I leave the bag in and pull the wort out through the spigot at the end of the mash. So realistically speaking, wouldn't that be very similar to using a s/s braid and should yield similar results?

Thanks,

-Joe

If you are adding your sparge water in "batches" and stiring it into the grains, then you are batch sparging. If your are adding sparge water continuously to the top of the grainbed, and pulling the runnings out the bottom, then I would say you are fly sparging.

IMO the braid is simple, cheap and very effective, and should not be easy to damage. Just don't stir the mash like you are mixing concrete, no problems. Also, no need for a 3 foot long braid that will get all tangled and kinked. 8 - 10 inches is all you need.

8 - 10 inches is all you need.

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That's what she said.
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