Hollow lid on mash cooler = easy fly sparge setup?

This may be difficult to explain, but I have a ten gal Rubbermaid cooler that I use for my mash tun. I'm also about to install a pump to get the water from my kettle to tun.

The lid on my cooler appears hollow, and I want to get a fly sparge system going. I'm thinking about drilling a hole in the top/exterior of the lid in which to place the tubing carrying the water from the kettle. Then I'm thinking of drilling a series of small holes on the bottom/interior of the lid to create a drip system. The water would enter the top of the lid, and disperse throughout the hollow lid while dripping down on top of the grain. Anyone done anything like this before? Any initial red flags I haven't thought of? Thanks!

An

zstar5000 said:

This may be difficult to explain, but I have a ten gal Rubbermaid cooler that I use for my mash tun. I'm also about to install a pump to get the water from my kettle to tun.

The lid on my cooler appears hollow, and I want to get a fly sparge system going. I'm thinking about drilling a hole in the top/exterior of the lid in which to place the tubing carrying the water from the kettle. Then I'm thinking of drilling a series of small holes on the bottom/interior of the lid to create a drip system. The water would enter the top of the lid, and disperse throughout the hollow lid while dripping down on top of the grain. Anyone done anything like this before? Any initial red flags I haven't thought of? Thanks!

An

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I like the idea. I checked out my round cooler mlt and the bottom of the lid was not straight or flat. All of the sparge water will flow to the edges instead of distributing evenly. I would have to flood it to get it to drain as intended. You would also need a pump that can handle the back pressure if attempting to control the flowrates. You may want to try gravity first. I am going with my original thoughts of using loc line. Widely used in industrial applications.

I would be concerned about the inside of the lid and biological growth. I know that boiling would kill things that came out but I still don't want to risk running my sparge way through unknown and unseen biological contaminants.

I would also be concerned with the insulation lost with drilling small holes on the inside of he lid. Perhaps drilling one hole in the middle and then building something to disperse the water over the grain. That was you can remove and let dry with peace of mind.

Gartywood said:

I would be concerned about the inside of the lid and biological growth. I know that boiling would kill things that came out but I still don't want to risk running my sparge way through unknown and unseen biological contaminants.

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Good point. But it could be rinsed out with soap and water. You could even use a bottle brush to clean the inside, so I don't think it would be too bad.

If you did this though, you might want a second lid for mashing, otherwise heat will escape through the holes... OTOH, 10 gallons of mash tends to hold its heat well enough in just a steel or aluminum pot, so I probably wouldn't worry about it.

The fact that the bottom of the lid is not flat, however... that could be an issue. As someone above me stated, you'd have to keep it flooded to ensure even distribution of the water.

I did have basically the same idea. I haven't done it yet though because I already get good efficiency with batch sparging. and I didn't like the idea of pumping hot water around, as I am an apartment brewer and much prefer transferring water from the stove to the MLT by way of 2L pitcher. I think a small mistake with a pump could just cause too much mess for me. Still... it's a good idea. If you do it, let us know how it turns out.

I think you would have trouble ever getting the inside dry. I drilled through my lid to run some tubing through and still can't get all the plastic shavings out.
The tubing is high temp silicone that floats on top of the mash while I fly sparge and it works great.
My understanding of the "shower effect" you are after is primarily used in conjunction with rake arms that mix the grain for efficiency.

Thanks for the input. After further examination, there are some "ridges" and "valleys" in the lid, so I would probably have to really flood the center valley in order to get any water over to the other valleys. And even then, I think the ridges may actually be touching the top of the lid, making water transfer impossible.

FWIW, I build a sort of spray manifold inside the lid of my mash tun, which is a little 5-gal round one (time to upgrade already!)... I used plastic bendable PVC tube with push-to-lock connections... one very short hose through the lid (with the obvious hose barb on top), through to a tee. One piece of tube, cut to length, is stuck into both sides of the tee to form a loop 'round the circumference of the lid, with one adel clamp around, tied to the inside of the lid with a self-drilling screw to hold in place/shape.

Then a number of tiny (maybe 1/32"?) holes are drilled into the tube at the right angle, which creates a nice fountain of water jets cross-firing across the center, a pretty little pattern of water to fly-sparge with. Interestingly enough, that hole size doesn't seem to accommodate more water flow (at normal gravity pressures) than we'd want for sparging... so the flow rate into the tun doesn't seem to be too tricky to adjust, just a matter of cracking the valve and then managing the outlet flow rate...

Wish I had pics, but I've been too busy building the more complex side of the rig...