Blichmann 10 Gallon MLT warped

Anyone else have this problem? I bought a 10 gallon Blichmann MLT with the false bottom and after a couple of batches I've noticed that the bottom of the kettle is warped and stained with burnt grain/flour.
Will the warped bottom be a problem and how did you clean off the blackness?
I have a 15 gallon Blichmann for the boil kettle and it doesn't have this problem.

i dont have experience with them, but it sounds strange.

what are you using as heat source?

Scottie2Hottie said:

i dont have experience with them, but it sounds strange.

what are you using as heat source?

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It's a 3 tier system on propane. I would think the boil kettle would be worse since it has the wide open throttle for a lot longer.

What is your process? Are you direct firing the MLT? If so, are you circulating while you heat?

Sounds like scorching to me.

Boerderij_Kabouter said:

What is your process? Are you direct firing the MLT? If so, are you circulating while you heat?

Sounds like scorching to me.

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I am continuously stirring while heating but there may not be enough liquid to circulate under the false bottom. I'm more surprised at the warping of the bottom than I am the degree of scorching.

If you are direct firing, I really suggest circulating the mash liquor with a pump. Obviously you are making good beer doing what you are doing, but circulation will make the temps 100% easier to target and control without temp spikes and scorching.

The Blichmann kettles are pretty thin walled but it is still surprising that it would warp. Maybe you were somehow building pressure under the mash and the temps got really high??? That is a weird one to me.

Boerderij_Kabouter said:

If you are direct firing, I really suggest circulating the mash liquor with a pump. Obviously you are making good beer doing what you are doing, but circulation will make the temps 100% easier to target and control without temp spikes and scorching.

The Blichmann kettles are pretty thin walled but it is still surprising that it would warp. Maybe you were somehow building pressure under the mash and the temps got really high??? That is a weird one to me.

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I have a 15 gallon Polarware that I've been using also and it has a false bottom also and it's never had this kind of problem but the design is different, it's just holes like a regular FB has where as the Blichmann has it's patent pending design and perhaps it allows the heat to build up more than a regular false bottom? It works great filtering but if it's letting the heat build up this much then perhaps that's going to be a problem with scorching and adding a roasted flavor to the beer.

If you are getting scorching I would try to figure out why and fix it. I doubt you will be able to stabilize your flavor profile with scorching. That sounds like it has inconsistent batches written all over it.

Boerderij_Kabouter said:

If you are getting scorching I would try to figure out why and fix it. I doubt you will be able to stabilize your flavor profile with scorching. That sounds like it has inconsistent batches written all over it.

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I agree. I just sent off an e-mail to Blichmann Engineering to see what they think about this. It could be a combination of too fine a grind allowing flour to build up on the bottom (under the false bottom) and the type of false bottom Blichmann sells not letting enough heat to circulate. Meanwhile I'll just use my Polarware until this gets resolved. I'll still use my 15 gallon Blichmann for the boil kettle, no false bottom or mash to deal with.

Heard back from John Blichmann and he agrees with you that the wort needs to be circulated during the heating process. He said that the stirring does nothing to circulate the wort under the false bottom. So this means extra work unless I invest in a pump system. Hmmm, something to ponder.

A pump is only $150 with all the fitting and everything... after I bought one I couldn't remember how I possibly managed to brew before. I am just being the devil

Boerderij_Kabouter said:

A pump is only $150 with all the fitting and everything... after I bought one I couldn't remember how I possibly managed to brew before. I am just being the devil

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Oh go sniff a donkey! I use a 3 tier system so I'm used to gravity (which is free, for now) so this would be the only thing I can think of to need the pump for. Thank you for the help, it's always appreciated.

you know you want a pump hahahahahahahahahahahhahahadon't listen, gravity works fine

hahahahaha

always glad to help

Pump ordered. The Debil won ageen. Eventually I'll need/want a plate style chiller and need the pump for that. I'm sure it will come in handy. I'll just keep reminding myself of that.

Hahaha. I actually laughed out loud. Well, I am sure you won't be disappointed, they really do come in handy. Plus now you can do a whirlpool chill with your immersion chiller, or circulate ice water. Or you could start using your immersion coil as a HERMS for stabilizing mash temps...

Boerderij_Kabouter said:

Hahaha. I actually laughed out loud. Well, I am sure you won't be disappointed, they really do come in handy. Plus now you can do a whirlpool chill with your immersion chiller, or circulate ice water. Or you could start using your immersion coil as a HERMS for stabilizing mash temps...

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So I got the pump. Now in order to keep the scorching from happening do I just set it up like a constant Vorlauf? As well as stirring during the heating process?
Thanks for the help. None of my books mention recirculating during a heating of the mash process.

HBHoss said:

So I got the pump. Now in order to keep the scorching from happening do I just set it up like a constant Vorlauf?

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Yup, a constant, slow wort recirculation throughout the mash tun. I don't recommend recirculating more than a 1/2 gallon per minute, otherwise the grain bed may literally cement itself to the false bottom and the pump will cavitate.

HBHoss said:

As well as stirring during the heating process?

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No stirring is necessary (or recommended) after dough-in.

That's right. Just a slow circulation to keep things moving.

I have cleaned out my PM box now btw.

Boerderij_Kabouter said:

That's right. Just a slow circulation to keep things moving.

I have cleaned out my PM box now btw.

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Here's my recirculation setup. Look workable to you?

Perfecto! Step mashing will be soooo much easier for you now.

Boerderij_Kabouter said:

Perfecto! Step mashing will be soooo much easier for you now.

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Awesome, thanks.

Just saw this thread. I think it's crap that the most expensive pot on the market would warp, I don't care what your process is. That is telling. Telling me not to buy one.

wildwest450 said:

Just saw this thread. I think it's crap that the most expensive pot on the market would warp, I don't care what your process is. That is telling. Telling me not to buy one.

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Any equipment used improperly can result in failure of said equipment. These pots are very nice and well built and there's obviously something wrong with the process and the handling of the pot that made this happen.

Looking at your pictures I see 2 things you might want to change with your pump setup. One is the orient the pump head vertically to aid in priming, and the second is to add a ball valve on the outlet side of the pump to control your flow. Its bad for the pump to be controlled by the valve on the pot. So when you are recirculating, your MLT valve should be wide open and you should be throttling the flow at the outlet valve on the pump.

RiverCityBrewer said:

Looking at your pictures I see 2 things you might want to change with your pump setup. One is the orient the pump head vertically to aid in priming, and the second is to add a ball valve on the outlet side of the pump to control your flow. Its bad for the pump to be controlled by the valve on the pot. So when you are recirculating, your MLT valve should be wide open and you should be throttling the flow at the outlet valve on the pump.

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Cool, thanks. I can do that.

RiverCityBrewer said:

Looking at your pictures I see 2 things you might want to change with your pump setup. One is the orient the pump head vertically to aid in priming, and the second is to add a ball valve on the outlet side of the pump to control your flow. Its bad for the pump to be controlled by the valve on the pot. So when you are recirculating, your MLT valve should be wide open and you should be throttling the flow at the outlet valve on the pump.

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Are you suggesting these items led to the warping? I can't imagine it would matter.

pickles said:

Are you suggesting these items led to the warping? I can't imagine it would matter.

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I think what led to the warping was the build up of heat by not recirculating the wort. Also because I'm using a finer grind then I used to it was allowed to cake up and burn on the bottom of the MLT concentrating the heat in one spot. A combination of factors led to the warping. All of which (I hope) have been addressed. I'll know tomorrow when I dump my grains from tonight's brew session.

Did you lift or try to lift the kettle by the handles while it was full? Those kettles are paper thin and lifting it when full could cause it to deform. I think they warn you not to lift it when full and that may be the reason. I can't imagine that the warping would be due to overheating. The kettle will only get to boiling temps or maybe a little more than that if it contains liquid.

Catt22 said:

Did you lift or try to lift the kettle by the handles while it was full? Those kettles are paper thin and lifting it when full could cause it to deform. I think they warn you not to lift it when full and that may be the reason. I can't imagine that the warping would be due to overheating. The kettle will only get to boiling temps or maybe a little more than that if it contains liquid.

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No, I never have tried to lift it when it's full. Heat is the only thing I can think of that would do it.

It is pretty clear in the directions that the false bottom is not intended to be in place when direct fire is applied to the bottom of the kettle.

FWIW, the 10 gal boilermaker doesn't deform/warp to any noticable degree when lifted at almost full. I've lifted mine when almost full many times (only at dough-in temps, I wouldn't lift it while really hot).

Also FWIW, I direct-fire mine all the time and do not get any scorching at all. But I'm mashing on a kitchen stove and do not crank the heat wide open. At the end of a mash I can just rinse the kettle and it's shiny stainless even on the bottom. I rarely recirculate, maybe an occasional quart at a time just to ensure all the liquid below the FB gets above it (I've always just assumed that when heating the enzymes under the FB are denatured). I stir at ~5 min. intervals during heating with an upward motion from the bottom, sort of getting the whole thing to 'roll' in the pot. I often direct-fire to mashout and usually go from the mid-high 150s to 168* F in just 5-10 minutes...with a shiny stainless bottom of the pot at the end. It can be done just don't rush it.

StAnthonyB said:

It is pretty clear in the directions that the false bottom is not intended to be in place when direct fire is applied to the bottom of the kettle.

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That's not true. I have the instructions in front of me and it only says not to use the FB as a boil screen, only as a mash filter. I did find a word of caution about excessive heat causing scorching and possible damage to the bottom. I guess my burner is hotter than I thought.

I was going to eventually upgrade to Boilermakers, but I really don't like the idea of a thin-walled brewpot without three-layer bottom that will flex just by lifting it when full.

Even with recirculating, my last brew did have some scorching though not nearly as much as before. I'll turn down the flame even more on the next batch.
For those of you applying direct heat to the MLT, typically, how long does it take you to get to your desired mash temp for a 10 gallon batch?

HBHoss said:

Even with recirculating, my last brew did have some scorching though not nearly as much as before. I'll turn down the flame even more on the next batch.
For those of you applying direct heat to the MLT, typically, how long does it take you to get to your desired mash temp?

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It depends on the batch size, the dough in temp, the grain bill, the cirulation rate, the flame intensity and the ambient conditions. My temp ramp up rates vary from 1 to 3 degrees/minute. I can heat the strike water in the MT and hit my mash temp right away. OTOH, I frequently do step mashes doughing in at 95 F and ramping up with direct heat from there.

The potential for scorching is one of the major drawbacks of using stainless steel vessels for brewing. SS does not distribute heat very well at all and this results in concentrated hot spots where the burner flame contacts the kettle bottom. I use a 12" dia x 1/8" thick copper heat diffuser plate under my kettle to mitigate the problem. This was a major improvement, but it wasn't cheap.

Catt22 said:

It depends on the batch size, the dough in temp, the grain bill, the cirulation rate, the flame intensity and the ambient conditions. My temp ramp up rates vary from 1 to 3 degrees/minute. I can heat the strike water in the MT and hit my mash temp right away. OTOH, I frequently do step mashes doughing in at 95 F and ramping up with direct heat from there.

The potential for scorching is one of the major drawbacks of using stainless steel vessels for brewing. SS does not distribute heat very well at all and this results in concentrated hot spots where the burner flame contacts the kettle bottom. I use a 12" dia x 1/8" thick copper heat diffuser plate under my kettle to mitigate the problem. This was a major improvement, but it wasn't cheap.

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So it could take you an hour to an hour and a half to reach 154 degrees with a typical 15 lb. grain bill? It took me an hour to go from a cold start of 60 degrees to 154 degrees while recirculating. Where did you get your copper plate?

HBHoss said:

So it could take you an hour to an hour and a half to reach 154 degrees with a typical 15 lb. grain bill? It took me an hour to go from a cold start of 60 degrees to 154 degrees while recirculating. Where did you get your copper plate?

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A 15 lb grain bill for a 6 gallon batch on my system would be about a 1.075 OG or thereabouts. I can ramp up temps much faster when brewing 6 gallons vs 12. This is simply due to the fact that I can "turn over" the entire mash volume much faster when pumping. The temp ramp rate for this batch size and grain bill would be on the higher side at about 3 deg/min, so it would only take about 20 minutes to get to 154 F a dough in at 95F. I've recently made some changes which I think may have improved the rate some, but I haven't done any timing tests since, so I can't say for sure. One of the problems with direct firing a MT is that pushing for high pumping rates can lead to the mash sticking and/or pump cavitation. The trick is to pump as fast as possible with the heat as high as possible. Some experience is required to get the balance right in order to maximize the ramp up rate and avoid sticking.

Here's a link to the copper plate source. Keep in mind that these only work well with flat bottomed kettles:

http://store.electrical-insulators-and-copper-ground-bars.com/index.html

I think I paid close to $100 for the one I have.

Thanks.

Ouch Catt22; for 0.094" or 11 gauge of 20" diameter copper they're price is $139.95. No wonder our electrical contractors get pissed off when we waste wire on long wire pulls. Hoss, time for some midnight country backroad manhole collecting for a burner plate.

BrewBeemer said:

Ouch Catt22; for 0.094" or 11 gauge of 20" diameter copper they're price is $139.95. No wonder our electrical contractors get pissed off when we waste wire on long wire pulls. Hoss, time for some midnight country backroad manhole collecting for a burner plate.

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Too bad we don't have man holes to cover.