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Mash Tun Flow Rate

I’ve been all-grain brewing for several years now. I had a 48-qt Igloo Cube with a circular braid in the bottom. I wanted to make some heavy brews and possibly 10-gal batches so I made a new tun from a Coleman 70-qt Xtreem with a long braid running it’s length. I made 3 brews in the new tun without any issues. Yesterday I made NB’s Brickwarmer Holiday Red All Grain Kit and after mash-in it stuck mid-way. I think I had the valve too far open. On the batch sparge I lessened the flow rate and drained almost every drop of wort. I was thinking the new tun has a larger valve and capable of flowing much more liquid. This made me wonder is there an optimal flow rate?

Thanks,

Mike

While I’m sure there is an optimal flow rate, I think it depends on so many factors that I’m not sure you can make a specific rule. A couple of the biggest factors are probably crush and grain bill. Some grains will cause a stuck sparge worse than others.

What seems to work pretty well for me is to start the drain slow and recirculate until it runs clear. Slowly increase the flow rate over a couple minutes until I have the valve wide open. Or if I’ve got a lot of rye, wheat or flaked grains in the grain bill, keep it slow.

Might be becasue the braid is too long. A few inches is all you need.

Here is a picture of the tun:


http://smg.photobucket.com/user/mbg/media/Brewing/IMG_0003_zpsc0866148.jpg.html

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Hi Denny, you’ll have to explain that one to me. With a longer braid and the same diameter port, you should get lower flow rate at any given surface area of the braid, thus reducing the chance of clogging. Or so it seems to me. I’ll agree though that you only need a few inches.

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Hi Denny, you’ll have to explain that one to me. With a longer braid and the same diameter port, you should get lower flow rate at any given surface area of the braid, thus reducing the chance of clogging. Or so it seems to me. I’ll agree though that you only need a few inches.[/quote]

The thing is that wort doesn’t flow along all of that braid. It’s porous. It just passes through most of it. All the draining happens in the last few inches. As to the longer braid making for more runoff issues, it’s just a WAG. Probably has nothing to do with it. That’s what I get for drinking before thinking!

I agree with Denny, a long braid doesn’t really act as a long straw. The suction happens near the valve, and the liquid is pulled through the braid in that vicinity.

To your question, I’ve never seen flow rate cause issues with flow. Stuck mashes invariably come back to the fineness of my crush and the adjuncts used. I think a whole lot of the sticking has to do with how much protein is in the grain. I always rake my mash and that helps things keep flowing.

I use a BIAB bag inside my 10 gallon Igloo with a bazooka filter under it. Yeah, I know, it’s overkill, but it doesn’t have stuck sparges. Best of all, at the end of the mash, I lift out the bag and the tun just needs a couple of rinses to be ready to store away.

[quote=“tom sawyer”]I’ve never seen flow rate cause issues with flow. Stuck mashes invariably come back to the fineness of my crush and the adjuncts used. I think a whole lot of the sticking has to do with how much protein is in the grain. I always rake my mash and that helps things keep flowing.[/quote]I agree. All of my mash tuns have 1/2" full port IPS ball valves with 1/2" I.D. tubing, I go full bore once the grain bed is set with no problems.

Not sure if there is an optimum flow rate out of the mash tun but I like to run mine slow for a few reasons. I collect about 25-26 gallons of wort over the course of about 1.5-2 hours, heating in the brew kettle while I am collecting. That way, it is boiling as soon as I stop sparging. I have not had a stuck sparge since I put pumpkin meat in the mash a few years ago. I have 3 tuns and use the one which will hold the grain bill I am working with.

I don’t use a bag, I don’t get stuck runoffs, and all I do is rinse out my cooler, too. Glad you have a system that works for you, but it kinda seems redundant.

I can see some possible advantage to using a bag in a MLT as far as cleaning, but I hate rinsing a bag out more than I hate hosing off the cooler.

Dump the bag, rinse, drip dry, shake, done. Cleaning the bag doesn’t bother me. The stuck mashes and sparges I was getting before I got the bag bothered me.

Whatever works for you is what you should do. My approach would have been to find the cause of the stuck runoffs and fix that, but that doesn’t mean it has to be your approach.

Not to high-jack the thread, but what are some of the major causes of stuck sparges?
I have probably done 20 all-grain batches since getting into it two years ago. One time I had a stuck sparge when my braid broke during dough in (got my mix stir too low).

This past weekend I came close. I was brewing Denny’s BVIP and had one of the slowest runoffs I have ever had. I blow back through the hose a couple times but the flow rate would slow back down almost immediately. Are there ingredients in the BVIP that cause a slow runoff?
What would the fixes be?

[quote=“Roddy”]Not to high-jack the thread, but what are some of the major causes of stuck sparges?
I have probably done 20 all-grain batches since getting into it two years ago. One time I had a stuck sparge when my braid broke during dough in (got my mix stir too low).

This past weekend I came close. I was brewing Denny’s BVIP and had one of the slowest runoffs I have ever had. I blow back through the hose a couple times but the flow rate would slow back down almost immediately. Are there ingredients in the BVIP that cause a slow runoff?
What would the fixes be?[/quote]

Nope, nothing in the ingredients that would cause that. If you batch sparge, start the runoff slowly, than after you return the vorlauf portion to the tun, open it up.

[quote=“Denny”][quote=“Roddy”]Not to high-jack the thread, but what are some of the major causes of stuck sparges?
I have probably done 20 all-grain batches since getting into it two years ago. One time I had a stuck sparge when my braid broke during dough in (got my mix stir too low).

This past weekend I came close. I was brewing Denny’s BVIP and had one of the slowest runoffs I have ever had. I blow back through the hose a couple times but the flow rate would slow back down almost immediately. Are there ingredients in the BVIP that cause a slow runoff?
What would the fixes be?[/quote]

Nope, nothing in the ingredients that would cause that. If you batch sparge, start the runoff slowly, than after you return the vorlauf portion to the tun, open it up.[/quote]

That’s pretty much what I did. I trickled the first 2-3 quarts to allow the bed to settle, then turned it up. Do I need more than a couple of quarts before opening the spigot all the way?

I usually vorlauf less than a qt. Never more than 2.

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