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Keggle MLT Question/Comment

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hayabusa

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I have a keggle MLT w/ a copper manifold insulated with that Reflectix stuff (silver bubblewrap) and I have been losing about 5-9 degrees/hr; this past weekend I tried to direct fire the MLT to bump the heat up a few degrees which seemed to work but when it came time to clean it there was definitly some scorching happening (and that s$$t is hard to clean)

When direct firing it I had the flam on pretty low and constantly stirred up the mash to try and prevent any grains from resting on the bottom to long.

I do not want to use a cooler; I am not against a hot water tank element w/ a temp controller but would rather not have to use electricity and if I did that then I would put in in the HLT and make a HERMS but I am perfectly fine w/ single infusion batch sparging.

How are you guys direct firing your meggle MLT without scorching?? Are you using one of those flase bottoms and not a manifold to prevent scorching? I need to find a better way to heat the MLT to keep temps consistent.
 
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Thats how I do it! I can tweak strike temps, do step decoctions and raise to mash out temps without ever adding hot water or using direct flames. Usually I just do single step mashing but I always raise to mashout temps (never had a stuck sparge!). I can raise from 155 to 168 in less than 10 mins (5 if I want) with a typical 5 gal grain bill. Just keep the grains stirred as steam injects and all is good. The steam ring can easily be adapted for any application.
 
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hayabusa

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that's definitly interesting; I don't really have pressure cooker to get steam injection working.

I tihnk that the keggle, even with the refletix insulation is going to lose to much heat and I either need to switch over to a rubber-insulated keg or start with a thicker mash and raise my mash temp every 15/20 mins to end up with a total volume of 1.25(ish) qt/lb for the first runnings..... I have a pump but didn't want to to HERMS since batch is just easier and almost as effective. The steam idea does have me intrigued though and if I can find a cheap pressure cooker I may give it a try.

I still want to know how folks are direct firing the mash without scorching.
 

menschmaschine

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I use a direct-fired MLT keggle. It sounds similar to yours with reflectix, etc. I use a stainless steel false bottom, so, with proper stirring, scorching is much less likely. Sometimes, on a cold brew day, I'll put the burner on very low while stirring if I think I'm losing too much heat.

Do you insulate the lid in any way? I found this can reduce heat loss dramatically. I went from losing 5°F per hour to maybe 1°F on a warm day. I put a folded up blanket over the lid and it keeps the heat in much better. I also have 3 layers of reflectix around it.
 
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hayabusa

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I use a direct-fired MLT keggle. It sounds similar to yours with reflectix, etc. I use a stainless steel false bottom, so, with proper stirring, scorching is much less likely. Sometimes, on a cold brew day, I'll put the burner on very low while stirring if I think I'm losing too much heat.

Do you insulate the lid in any way? I found this can reduce heat loss dramatically. I went from losing 5°F per hour to maybe 1°F on a warm day. I put a folded up blanket over the lid and it keeps the heat in much better. I also have 3 layers of reflectix around it.
I made a reflectix lid but I will go with a blanket on top of it for the next batch; i think with the false bottom you are not allowing much grain at all to touch the bottom of the keggle where my manifold doesn't give me that - i think that is the main difference and probably the root of my issue. I may opt for the false bottom as a test but it's ~$40 which is a bit much for a test... did you make, or purchase yours? does it fit perfectly so no grain touches the bottom of the vessle?
 

menschmaschine

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I bought this one which was made specifically for a Sankey keg... yeah, a bit pricey, but scorching is one of the main reasons I bought it.
 

Bobby_M

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You need a large false bottom and a pump. The heat must only be applied to areas where mash liquid touches and it has to be removed quickly to avoid overheating.

I also use reflectix but I treat it almost like a cooler. Strike water is heated directly in the MLT but I overshoot by 5F. Flame off, reflectix on. I then stir until the temp drops to strike temp. This heats the air in the reflectix bubbles and in the airspace between the keg and insulation.

I've done maybe 8 batches like this and I hope to build a HERMS or electric fired heat tube by next winter.
 
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hayabusa

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You need a large false bottom and a pump. The heat must only be applied to areas where mash liquid touches and it has to be removed quickly to avoid overheating.

I also use reflectix but I treat it almost like a cooler. Strike water is heated directly in the MLT but I overshoot by 5F. Flame off, reflectix on. I then stir until the temp drops to strike temp. This heats the air in the reflectix bubbles and in the airspace between the keg and insulation.

I've done maybe 8 batches like this and I hope to build a HERMS or electric fired heat tube by next winter.
so I have to recirculate to direct fire? makes sense now that you say it but it almost makes the point to HERMS it up and just keep the HLT to temp.... i guess it's only a few QD's and 50ft of copper more...... all of which I was trying to avoid. This hobby is a money pit. :):mug:
 

menschmaschine

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I wouldn't say you need a pump for direct fire. It may be ideal, but not absolutely necessary. I've direct-fired step-mashed (no pump) several beers with no scorching taste in the beer. I just stirred a lot while the burner was on and didn't put the burner on high.
 

JoeBob

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Do you have a deflection plate under your mash tun? I friend of mine has an old brew magic and above the burner is welded a steel plate about 8" in diameter to deflect the heat. It takes a bit longer but there is no scorching 10 years into it. We also recirculate while mashing and there is a false bottom, which ties into what was said earlier. I guess all three together add up to a clean keggle!
 
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