HERMS recirculation

so this topic only moderately fits in the subject of electric. I can relocate if needed. I'm building an eherms system. going great. had a questions related to mash recirculation:

the internet is basically saying that during mash, you can run your pumps wide open as long as you don't get a stuck sparge. Cool. but during sparge you have to basically trickle to prevent channeling. Why can channeling only happen during sparging and not during mash recirculation? Is it because it starts all mixed up and most of the conversion happens in the first 10 min or so?

Thanks!

channeling during recirc likely happens as well, but it's not as critical, as the rest of the mash (non-channeled area) has enzymes working in it as well. it might fluctuate in temp a bit more, but it probably doesn't cause major problems.

the recirc with a HERMS is interesting to me. I don't know the intricacies. I don't know if slow vs fast helps with conversion or not. i know fast is better for temp ramps, obviously. i also know that if you run full open with a chugger pump, you WILL compact some mashes, others maybe not as much, depends on what is in the grainbill and how full the mashtun is

M25 said:

so this topic only moderately fits in the subject of electric. I can relocate if needed. I'm building an eherms system. going great. had a questions related to mash recirculation:

the internet is basically saying that during mash, you can run your pumps wide open as long as you don't get a stuck sparge. Cool. but during sparge you have to basically trickle to prevent channeling. Why can channeling only happen during sparging and not during mash recirculation? Is it because it starts all mixed up and most of the conversion happens in the first 10 min or so?

Thanks!

Click to expand...

Channeling might occur if you run full open, but that's not the primary reason for going slow during fly sparging. And if you're batch sparging you can pretty much go full open.

During fly sparging you want to go slow to give the sugar time to diffuse into the sparge water that has a lower concentration of sugar than the surrounding grain.

Channeling during fly sparging greatly reduces the amount of contact the new sparge water has with the grain from the point it enters the mash until it is recovered. And the grain it does contact along the channel will be mostly depleted of sugars.

During the mash the more critical issue is maintaining target temp throughout the grain bed. Channeling isn't as big an issue there, even though it would be better if it wasn't happening.

In my eHERMS system I dough in and then let the grain settle for a few minutes before I start recirculation. When I do start recirculation I only crack the valve open a little and gradually open a little more and a little more. My hope is that I'm reducing the chances of channeling and/or a stuck mash.

M25 said:

so this topic only moderately fits in the subject of electric. I can relocate if needed. I'm building an eherms system. going great. had a questions related to mash recirculation:

the internet is basically saying that during mash, you can run your pumps wide open as long as you don't get a stuck sparge. Cool. but during sparge you have to basically trickle to prevent channeling. Why can channeling only happen during sparging and not during mash recirculation? Is it because it starts all mixed up and most of the conversion happens in the first 10 min or so?

Thanks!

Click to expand...

This is a good question. As enzymes start the conversion process it's desirable to release sugars simultaneously into wort. This requires a flow of low sugar concentration wort past a zone of converted grains at a higher concentration. It is therefore important to reduce channeling while mashing to maximize flow around all grains. I make every attempt to keep my grain bed loose and less resistant to flow while mashing with RIMS. I want maximum grain exposure to circulation. I will normally use a low flow and stir the grain bed about 10 minutes into, halfway through and just before ramping up for mashout and sparge.

I also have been stirring up my mash after 15-30 minutes if i find the mash is pretty compacted. it seems to stay loose after that. not sure if it really does much for my conversion or lautering, haven't compared directly

Like many others here i just run full open, i open it just a bit to start and let it run for a minute or two and then slowly open it up to full and leave it there.

I think how open you can run without getting stuck really is a matter of grist but also your false bottom.

Depends on the pump too. Isn't the chugger higher flow than the March for the usual homebrew pumps?

Thanks for the comments everyone! It helped clear it up. So it really does happen but most do things to prevent this causing any issues such as stirring the mash. Good point Gameface on the other reason the go slow through a sparge. IE giving the fresh water time to soak up the sugars when passing through the grain bed.

On my set up, I have to take account of batch size. I cannot run wide open on 5 gallon batches unless it's a big beer with a big grain bill. I can watch the sight glass go up and down 2-3 gallons as the pump cavitates. I've read about false bottoms collapsing from the suction.

LarMoeCur said:

On my set up, I have to take account of batch size. I cannot run wide open on 5 gallon batches unless it's a big beer with a big grain bill. I can watch the sight glass go up and down 2-3 gallons as the pump cavitates. I've read about false bottoms collapsing from the suction.

Click to expand...

More grain reduces your chances of a stuck mash? Any idea why that is?

More grain = more water. The grain bed floats higher off my false bottom. 15 or more pounds of grain and I have 5 to 6 gallons of water. 6 or 7 pounds of grain, I'm only looking at 1.5-2 gallons of water. I even run my 5 gallon batches at 1.5 quarts per pound just give me a little more wiggle room.

My chugger pump will compact a grain bed like concrete. I've had to turn it off and break it up with a mash paddle before I learned to throttle it back. I can only imagine how much grain is being sucked into the FB holes. You want to talk about vacuumed packed. No way your getting water through it.

Mine runs better with less grain in the mash tun, less force pushing down on FB I guess

My mash doesn't seem to really float no matter what.

i debate running the pump fast i did a small test once and o appeared to get a little better mash conversion with faster flow, but only maybe 3% i think

I'm sure a lot depends on equipment. Seems a smaller diameter longer coil will restrict flow more. I use 50' 3/8 close to full open on my LG. My last dozen or so batches have been full volume recirculation, no sparge. I dough in with my calculated strike volume, I have my sparge volume preheated in my BK. I circulate from the MLT-->BK-->HERMS coil-->MLT. Best beers I've made and a lot faster. I'm not looking back.