Bottom-up reciculation

I'd like to stir up some discussion about the idea of reverse or bottom-up reciculation. This could also apply to fresh, hot sparge water flushing.

In standard top-down reciculation we are inherently submitting ourselves to the risk of grain bed compaction and channelling. The water constatnly added on top and sucked out the manifold in the bottom causes the grain bed to tighen up and the wort to flow through paths of least resistance in the grain bed.

I'm theorizing that if the liquid is pumped from the bottom and clean wort collected from the top that the counter-action of flow vs gravity will cause more of a stirring effect keeping the grain bed moving and mixing at all times, never compacting it and eliminating channelling.

This concept is used in the Brewmeister home brew product, but I don't like it for a couple of reasons. First, it uses a seal on the bottom of the tun and a built-in pump. This just seems to be trouble for a DIYer to accomplish. Second is that it looks like it has a lot of little fiddly parts to put together to get the screen on top correctly.

How would you do it? What do you think of the problem that I'm trying to solve?

Bonus points for making the system work like a brewmeister so I can just pull out the "grain bucket" and start my boil in the same container but without the complication

I've played with something like this before. It's not terribly complicated to set up. All I did was turn my pump around so it was pulling from the top and feeding back into my spigot. It worked fine enough, but it didn't really provide much benefit when the rubber meets the road.

A grainbed should only be compacting if it's seeing a significant vacuum, and if that's happening the problem is the rate of recirculation. I was hoping that the bottom-up recirc would provide some stirring, but even at high through-put the water just carved a channel of least resistance. Plus, one of the advantages of a recirculating mash is that you get a nice, set grainbed for filtering, and recirculating backwards left me with cloudier wort.

Cloudier wort is an interesting result.

I intend to make this system single-vessel or at most double if you include a HLT, but i am planing to do something that involves lifting the grain out of the tun, either BIAB or a stainless mesh of some sort.

So you would suggest that compaction is a non-issue if the recirc is slow enough? I'm certainly in no rush to recirc, as long as my temps remain stable and my mash-out happens evenly across the bed.

If grain bed compaction is a problem (and you use a pump), look into building a grant.

MazdaMatt said:

So you would suggest that compaction is a non-issue if the recirc is slow enough? I'm certainly in no rush to recirc, as long as my temps remain stable and my mash-out happens evenly across the bed.

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I can only speak for myself, but I have never gotten a stuck grain bed that couldn't be fixed by stirring and slowing down the recirculation. Some people use rice hulls to help, too.

Cloudy wort is the result I would expect from reverse flow through the bed.

Without a grain bed that is at least semi-compacted, the light grist material will never really be filtered out.

I always viewed well-filtered clear wort as one of the key benefits of a conventional RIMS system.

While its feasible to do it, I guess I am not seeing the advantages of reverse flow outweighing the negatives.

MazdaMatt said:

Cloudier wort is an interesting result.
So you would suggest that compaction is a non-issue if the recirc is slow enough? I'm certainly in no rush to recirc, as long as my temps remain stable and my mash-out happens evenly across the bed.

Click to expand...

Things that affect recirc flow/rate and compaction:

1. Water/grain ratio - 1.75 to 2.50 is recommended
2. Grist Bill - Wheat, and corn/oats/rice are not your friends
3. RiceHulls - More of these alleviate the "gumming" that #2 provide, and allow a faster recirc rate.