Direct Fired MLT

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ziggy13

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I am in the process of building a 3 keg pump driven system and was planning on direct firing my mash tun. I don't think I'm looking to build a RIMS or HERMS as of now and was wondering if it's possible to direct fire a mash tun without scorching the grain?

My plan is to fire the HLT and BK with the huge Bayou Classic BG14 burners, while firing the MLT with the smaller BG12 burner. I was planning on recirculating the mash through my electric pump and directly back into the MLT. Would this work? I suppose I could also recirculate my mash through my 50 ft wort chiller inside the HLT, but I'm mostly concerned with the amount of time it will take to raise the temperature of the liquid for a step mash without direct firing the MLT. Any thoughts or input on this?

Also, this may be a silly idea, but is it possible to put a false bottom ABOVE the ball valve in a keg? Would this create too much dead space or is this not even possible? I thought having the grain bed that high above the heat would help prevent scorching, but I'm just guessing at this point.

I purchased this item: http://morebeer.com/view_product/10073//Maximizer_for_Mash_Tun_Hot_Liquor_Tank the maximizer from MoreBeer in the hopes of using it in my 1/2 barrel keg with false bottom. Now I see this might not work and I probably need a standard false bottom with regular fittings but am concerned about scorching if the grain is that close to the heat source.

Finally, is it possible to recirculate the mash back through your sparge arm...like a stainless rotating one? I am looking for options of what type of 'valve' to use to drop the mash back into the MLT.
 
I'm in the process of using a direct-fire mash tun as well. I think I'm going to have to just use a mash paddle to keep it stirred to avoid scorching the grains on the bottom. Having a false bottom on the keggle should help with this too I'm hoping.

I can't answer your other questions, but I'm sure someone here knows.
 
ziggy13 said:
I am in the process of building a 3 keg pump driven system and was planning on direct firing my mash tun. I don't think I'm looking to build a RIMS or HERMS as of now and was wondering if it's possible to direct fire a mash tun without scorching the grain?

My plan is to fire the HLT and BK with the huge Bayou Classic BG14 burners, while firing the MLT with the smaller BG12 burner. I was planning on recirculating the mash through my electric pump and directly back into the MLT. Would this work? I suppose I could also recirculate my mash through my 50 ft wort chiller inside the HLT, but I'm mostly concerned with the amount of time it will take to raise the temperature of the liquid for a step mash without direct firing the MLT. Any thoughts or input on this?

Also, this may be a silly idea, but is it possible to put a false bottom ABOVE the ball valve in a keg? Would this create too much dead space or is this not even possible? I thought having the grain bed that high above the heat would help prevent scorching, but I'm just guessing at this point.

I purchased this item: http://morebeer.com/view_product/10073//Maximizer_for_Mash_Tun_Hot_Liquor_Tank the maximizer from MoreBeer in the hopes of using it in my 1/2 barrel keg with false bottom. Now I see this might not work and I probably need a standard false bottom with regular fittings but am concerned about scorching if the grain is that close to the heat source.

Finally, is it possible to recirculate the mash back through your sparge arm...like a stainless rotating one? I am looking for options of what type of 'valve' to use to drop the mash back into the MLT.
Click to expand...
Wow lots of questions here. Let me see if I can help some as I has a similar system.
I direct fire my MLT and I don’t circulate. My thinking on this is that if I am drawing wort toward the heat of the fire at the bottom then I might be risking scorching. This could be just paranoia but I would rather not take the risk. Instead I just fire and stir it gently over a longer period of time. I have learned in my brewing adventures the more patient you are with you mash and any process the better the beer comes out in the end.
Putting the valve below the grain isn’t a terrible idea but you will have a ton of dead space.
The Maximizer will still work with a false bottom. I have the jaybird false bottom with the hole drilled in it and I could see this combo working very well. I might modify my dip tubes for this.
If want to recirculate the mash back through I don’t see why you couldn’t run it through the sparge arm. I use a SS shower head that flows at 2.5gpm. It has a valve on it already but I also use a valve on my Pump.
I hope this helps and that I‘m not giving you bad info.Cheers

Quick addition: I usually raise my step temps over a time period of 10minutes.
 
Thank you both!

@noodle23 I was under the impression that the actual grain would scorch, not the wort/mash water. Maybe I am wrong?
 
You could look at either way i guess. I mean when you vorlauf you still get some grain in there and you would be drawing those, while a small amount of grain, toward the flame and could scorch that. Like i said i could be paranoid.
 
You said you don't want RIMS or HERMS, but doing direct firing on the MLT and recirculating it is RIMS! What you're proposing to do will be just fine, but don't do a FB above the valve. You want your wort in contact with the grains, not sitting below it. The recirculation will take care of making sure you're not scorching anything. You really have to leave the wort sitting in one place a while to scorch it, so don't worry about it. Also, doing the direct fire method works well for raising your temp for mash out or step mashes.

You also don't need to invest in one of those whirly-gig type sparge arms. Many of use use about 36" of hose coiled in the top of the kettle as the return on the MLT. If you keep an inch or so of water above the grain bed, you don't have to worry about making sure you evenly distribute the water.
 
Gotcha.

@JonW I guess what I meant was I wasn't planning on running it through a heat exchanger/wort chiller in the HLT. You're right though.
 
Here's my last question. If I'm recirculating out of the valve in my direct fired MLT through a pump and back into the top of the direct fired MLT, is there any advantage at all to throwing a 50 foot wort chiller in the mix and sticking it in the direct fired HLT, thereby recirculating through the wort chiller in the HLT? Would that increase temperature steps being that it's going through 2 direct fired vessels, or should I just stick to recirculating back into the MLT and skip the HLT?
 
Doing the coil is a HERMS system, so pick one, not both. No advantage to doing both systems. There are some that use the direct fire to heat their strike water and then switch to doing the HERMS coil for maintaining mash temps. I've found that direct firing RIMS works very well and is much simpler to implement then the added complexity of HERMS.
 
I have a direct fire RIMS system as well. I use a blichman 15 gal for my MLT, and like others, found the brewmometer to be pretty useless once you dough in. I use it to get to my strike temp, that's about it. I have made a contraption out of two stainless T's, a couple of camlock couplings, and a short length dial thermo. This essentially measures the temp of the wort as it's being pulled through the pickup, and reads more accurately than the brewmometer.

Now, I'm on my third sparge arm. I started out with the coiled tubing on top of the grain bed. I was getting horrible efficiency out of it. So I made an H manifold out of CPVC. It worked, kinda. I'm now using just a Siphon Sprayer out of the top of my lid on the MLT. Works awesome. Last brew I hit 92% efficiency.

The one thing I have been doing after my first couple brews, as I bring my strike water up to temp, I have this thermo rig hooked up, then my tubing, and my pump, and am recircing throughout. This way, once i dough in, I dont' have to worry about temp loss once hooking everything up.
 
Dfess: can you post a picture of your siphon sprayer/lid? I'd like to see what spray head you're using. I was using one I bought at the local HBS but the rate of flow through it didn't create much spray. I recirculate at a pretty slow rate because once I switch to sparge/lauter I flow out to the BK at the same rate I'm flowing sparge water into the MLT from the HLT. I'm back to using the floating tube method and getting low 80s efficiency but 92% sounds amazing.
 
This is the short sparge arm. I use this for 10 gal batches or high gravity 5 gal batches.
short_arm.JPG


This is the longer sparge arm for smaller 5 gal batches. In both these pics, the tubing looks to be bent, and it is. But once you get the heat of the strike water/mash running through it, it straightens right out.

longArm.JPG


And this is the thermo do-hicky thing. Works much the same way the one from MoreBeer does. Built it myself and saved maybe 4 dollars. But i put it together myself!

thermoUnit.JPG
 
I do direct fire and it works fine, and seems to give better flavor but you have to keep the grain moving.
 
see, i've never mixed my grain bed after I doughed in. why do you have to keep it moving?
 
Wicked Daddy said:
Dfess: can you post a picture of your siphon sprayer/lid? I'd like to see what spray head you're using. I was using one I bought at the local HBS but the rate of flow through it didn't create much spray. I recirculate at a pretty slow rate because once I switch to sparge/lauter I flow out to the BK at the same rate I'm flowing sparge water into the MLT from the HLT. I'm back to using the floating tube method and getting low 80s efficiency but 92% sounds amazing.
Click to expand...

this was also with grain run through my MM3-2 mill (first time using it). I'm sure that had a bit of a helping hand!
 
Perfect. Thanks for the picks. That sprayer is the same as the one at my HBS. I'm giong to give it try and perhaps push a little more pressure through it. Love the temperature sensor. I think I'm going to need to build one. My MLT (Blichmann) has the temp on the kettle and that has worked well but having the temp as the wort comes off the bottom of the MLT would be really cool.
 
So from what I'm reading, the weldless thermometer I'll be installing towards the bottom of the MLT is really only useful for reading strike water temp? Meaning I want some sort of inline solution located between the output of the MLT and where I locate my input back into the MLT? Is that because the grain bed skews the temperature reading of a weldless thermometer solution?
 
The temp. probe in the middle of the grain bed can't measure how hot you are getting the wort coming out of the vessel. By the time it does measure a temp. change you have already overshot your goal.
I have been doing my mashing in my brew kettle while stirring and measuring temp. continuously, then dumping the whole thing into my lauter tun with a false bottom. This works great, problem is it's back breaking when I want to make a 10 gal. batch.
 

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