Batch Sparge Speed/Problems

[raceskier]

I've been brewing AG for a few years now.

My mashtun is a 10gal Rubbermaid cooler with up until now a stainless braid manifold. I had been having some minor issues with the manifold. I have maimed it from repeated handling and was beginning to have some minor stuck sparge problems. I batch sparge exclusively.

So, I decided, why not switch to a false bottom, for a more bullet-proof setup, at least handling wise? I got the nice stainless steel domed perforated false bottom unit, plumbed it in and did some "dry" runs with water and all seemed well. I checked that the false bottom was snug to the bottom of the mashtun and that it was held firmly there by the manifold.

Well today I'm in the middle of my first run with the new false bottom. I open the valve and am getting barely a trickle as compared to the flow I got with the stainless braid. I tried all of the normal unstick methods; blowing back in the hose, stirring and letting the mash re-settle, etc. I am still getting a very slow flow rate. I realize that when continuous sparging, people are getting total runoff times in the 1 to 1.5 hour range. With my old stainless braid setup, I could drain 3.5 gallons in 10 minutes easily. With the false bottom, I can see that it is going to be more like the 1 hour range.

Can anyone using the false bottom for batch sparging give me some idea of what kind of flow rates you are getting? Do I have some other issue going on?

 

[The Pol]

This is a grain bed problem moreso than a false bottom problem. I can easily get a gallon/min from my falsie if I really want to.

 

[JVD_X]

You want to make sure that the weight of the grain is not pushing the inlet part of the tube (the part under the screen) onto the bottom of the cooler. The cooler gets a little softer when you add 155 degree anything and the bottom with deform just slightly enough to allow the end to touch the bottom.

 

[Yooper]

How do you have the false bottom attached to your ball valve? A couple of times, I've hit the tubing with my mash paddle and dislodged it. I had to empty my MLT into a bucket, fix it, and pour it back.

 

[raceskier]

You want to make sure that the weight of the grain is not pushing the inlet part of the tube (the part under the screen) onto the bottom of the cooler. The cooler gets a little softer when you add 155 degree anything and the bottom with deform just slightly enough to allow the end to touch the bottom.

I was worried about that when installing the false bottom, so I installed a short length of copper tube in the center fitting of the false bottom with 8 vertical slots in it. Even pushed down firmly against the tun bottom, it will still flow. I am beginning to think grainbed myself.

 

[raceskier]

How do you have the false bottom attached to your ball valve? A couple of times, I've hit the tubing with my mash paddle and dislodged it. I had to empty my MLT into a bucket, fix it, and pour it back.

I thought of that as well and hose clamped the fittings on both the false bottom and the valve.

 

[JVD_X]

I was worried about that when installing the false bottom, so I installed a short length of copper tube in the center fitting of the false bottom with 8 vertical slots in it. Even pushed down firmly against the tun bottom, it will still flow. I am beginning to think grainbed myself.

The screen will not get all the grains on the first run. Quite a bit can get through. Those 8 slits are probably clogged.

 

[raceskier]

Well, I got through my brew day with some patience. It took a couple extra hours to complete the sparge with the slow flow.

A post-mortem tear down, showed that JVD-X probably had the answer. I found about a quarter cup of fine grain bits under the false bottom. They were most likely clogging the slotted tube I had in the false bottom fitting. I'll pull out the tube for my next try with the false bottom. I'll just have to re-circ a bit more.

During the tear down it appears I probably left a quart or two more of wort than I would normally be able to extract with the braid manifold. It's not worth the headache of the long sparge though. Interestingly, my efficiency was very high for this brew at 79%. Perhaps an artifact of the very long sparge?

 

[Bobby_M]

I'm convinced this is just a fact of life with false bottoms.I used to have 1/2" tall slots in my pickup tube with the bottom laying dead flat on the tun bottom. I eventually made the slots twice as wide, and more like 1/4" tall and I leave less wort now.