Mistakes during first recirculation attempt

I didn't really think through the issues I might have when I attempted my first recirculation. The wort would not flow through my manifold fast enough to keep up with my chugger, even when the output of the pump was turned down to the point where it was barely a trickle coming back into the mash tun.

I'm guessing the grain clogged the slots in the manifold enough to slow down the flow. I'm trying to think of low cost solution to fix this issue for a couple of reasons, the main one being my budget is limited right now. I use an Igloo cube as a mash tun, so a false bottom is out of the picture.

Could I basically mash in a bag on top of the manifold to alleviate the problem? If I MIAB, should I just remove the manifold completely?

All said and done, I hit my efficiency numbers, but had A LOT of hot side aeration which worries me a little bit.

Thanks for any input.

The solution is to use a grant.

A grant is simply a vessel (I use a 2 gallon bucket) into which the wort can flow via gravity, from which it is pumped back into the mash tun. It eliminates the possibility of the pump drawing a suction on the mash tun outlet port and compressing the grain bed.

It also provides a convenient place to measure the wort's ph, gravity, and temperature while recirculating. It also allows you to keep the wort flowing continuously once you've started recirculating, without having to close the valve and redirect the wort to the boil kettle (risking disrupting the grain bed).

I use a plastic 2-gallon bucket I bought from ULine, to which I added an outlet port, valve, and hose barb. I let the wort trickle into the grant, and once the level has risen above the outlet port, I pump the wort back into the mash tun at the same rate it's flowing into the grant. When the wort is clear enough, I shut off the pump, lift it up (to drain the lines), take the hose off the pump and move it over to the boil kettle (with the wort flowing from the mash tun into the grant the whole time, so as not to disturb the grain bed), and collect my first runnings.

You can see it in action in this thread.

I would use the bag and the manifold next time, just make sure you don't over-fill the bag(s). The grain is going to expand substantially and if it gets too tight in there it will negatively impact your mash efficiency.

When you get the funds together a mash tun with a false bottom is going to be ideal for a recirculating mash because it's going to help eliminate problems like grain bed compression and channelling.

Also, you should have a ball valve on your chugger's output side so you can control flow. Slowing recirculation down will help with these problems as well.

I do have a valve on the pump output. I couldn't slow it down enough and still push it through the HERMS coil though. I'm thinking now of maybe scrapping the HERMS next time.

I second Kombat's idea. Also, if you're using slotted pipes, are they open-side down? That might help to keep them from getting clogged.

dirkomatic said:

I do have a valve on the pump output. I couldn't slow it down enough and still push it through the HERMS coil though. I'm thinking now of maybe scrapping the HERMS next time.

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I want to talk you into trying at least one more time. Theres some great advantages to a recirculating mash and working out the kinks is just part of this hobby.

Since a false bottom is out of the question for the time being, a combination of all the above suggestions ought to help: a wort grant, grain bags, and an upside down manifold.

Just make sure you can still prime your pump from whatever you use as a grant.

Yes, the slots in my manifold are facing down. I'll have to see if I have enough stuff to cobble together a grant... Unfortunately, all my tubing and pump have camlock fittings, so the cost of something like that adds up quickly. But maybe I'll just try the bag first.

Thinking about this even more...

My HERMS coil is in a small kettle on a hot plate. What if I just did away with the coil, made a small grant out of a bain marie pot and heated the grant with the hot plate if my ITC determines the temp drops?

I kind of like that idea... Any reason why that wouldn't work?

That sounds like a great solution. Brew on.

On the way home, I stopped by the store and they had a little 2 qt kettle for 6 bucks. I've got everything to put a port on it... I'll get that done tonight and try it on my next brew. Thanks!

Just curious have you tried using rice hulls to help form a filter below the grain bed? I had this problem in my setup (although mine is very different) but the rice hulls at about 10% of the grist did the trick. I think I paid $1.25 a pound for the hulls. And for a 10# grain bill used about a gallon bucket scoop of hulls and it was like magic. If I'm brewing with any type of flake, I use more hulls.

jcc4507fly said:

Just curious have you tried using rice hulls to help form a filter below the grain bed? I had this problem in my setup (although mine is very different) but the rice hulls at about 10% of the grist did the trick. I think I paid $1.25 a pound for the hulls. And for a 10# grain bill used about a gallon bucket scoop of hulls and it was like magic. If I'm brewing with any type of flake, I use more hulls.

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No, I didn't try rice hulls. This was my first attempt at recirculation and I hadn't ever needed them before. I'll go get some for the next brew and read up on how to use them...

They/Rice Hulls, don't impart any flavors or fermentable sugars so ultimately you could use however much you want. But there is a 'magic' number to not waste your money. In my setup I used the 10%ish rule per pound of grain, and it worked out great. (I don't recall where I read about it for reference. But it was on this forum.)

I add them just prior to dough-in then pour in and stir grain as usual. Then sit back and recirculate.

Another trick I learned in stuck recirc is to pump a little bit of HOT water through your drain port on the mash tun. I've had to do this on batches with flaked oats, maize, and the like. Also this helps if you mash at lower temps and fly sparge. I'll use this just prior to starting my sparge. Works wonders and saves me a lot of time!! Hope this helps and saves you $$!

Ok. Got my grant put together... It's a cute little bugger. Got a couple pics when I did my leak test. Can't wait to try it out!

Wow, nice! Looks way nicer than mine! Let us know how it works out for you.