Author Topic: Kettle Mashing Question  (Read 6889 times)

Offline ckpash88

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Kettle Mashing Question
« on: November 26, 2012, 07:57:34 PM »
So I brewed on thanks giving with my new set. It's a direct fired Boilermaker with a pump to recirculate during mashing.

The problem I was having I think were really bad hotspots. I would read the Brewmometer on the side and it would dip to 140 degrees on the dial the. I would put a thermometer in the mash and it would say 160.

When the Brewmometer would say 140 I would put the heat on and stir then in a couple of minutes I would bring it up to 152 my target temp.

Should I be stirring the mash almost all the time and if so should I be running the pump to recirculate while doing this?


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Offline bluesman

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Re: Kettle Mashing Question
« Reply #1 on: November 26, 2012, 08:15:17 PM »
Do you have a false bottom?

I use the Blichmann kettle for my RIMS. I heat/recirculate using a false bottom with a moderate flame (KAB4 burner) and get some temperature gradients in the tun, but usually +/-3 degrees during the heat/recirculate without stirring. Stirring the mash should only be necessary after the initial infusion and upon sparging.

How do you infuse and/or recirculate your mash liquor?
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Offline a10t2

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Re: Kettle Mashing Question
« Reply #2 on: November 26, 2012, 08:19:13 PM »
Have you calibrated the thermometers?
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Offline hopfenundmalz

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Re: Kettle Mashing Question
« Reply #3 on: November 27, 2012, 05:33:14 AM »
Sean has one obvious point, calibrate your instruments. I check the thermometers in my vessels vs the thermopen. The pH meter goes through a calibration with calibration solutions. Refractometer is checked with distilled water. And so on.

The pump return on my system is just the hose submerged under the wort. I give the mash a good stir to even out the temp.

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Offline ckpash88

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Re: Kettle Mashing Question
« Reply #4 on: November 27, 2012, 06:25:17 AM »
I calibrated my equipment before i started both of my thermometers and brewmometer are the same.

I also have a false bottom as well in my brew kettle.

I infuse the first step which was like (i am estimating i don't have my recipe in front of me) 4.25 gallons of 169 degree water to 13.5 pounds of grain. I then stirred for a moment to get it mixed up then turned on my pump to recirculate.

After about ten minutes i would have to stop the pump (if i didn't stop the pump i would lose prime and fight that for a while) and stir to get the heat distributed more evenly.
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Offline dcbc

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Re: Kettle Mashing Question
« Reply #5 on: November 27, 2012, 07:11:48 AM »
I would suggest taking your temperature somewhere in the return loop to the kettle and keep the recirculation rate fairly quick (but not so fast that it sticks).  On my setup (direct fired rims with 20 gallon kettle and false bottom), I keep the flame low, recirc with the valve on the high output march pump about 1/4 open, and take the temperature with a probe on the output side of the pump.  My temps are pretty consistent between my controller, my kettle thermometer, and the handheld thermometer I use to randomly check the mash temps and wort return.  I use a piece of flexible/adjustable tubing from brewhardware.com as my wort return.  I place it just beneath the surface of the mash toward the side.  There is a little whirlpooling of mash liquor, but minimal aeration. 
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Offline dean_palmer

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Re: Kettle Mashing Question
« Reply #6 on: November 27, 2012, 07:52:54 AM »
My mash tun is also a direct-fire keggle with a RIMS tube and a false bottom. Mostly 10 gallon batch sizes. I do stir for a while as the temps stabilize, and a few times during the mash session to even them out. No matter what you do there will be temp differences, especially when the outside temps are cold, and there is nothing wrong with gentle stirring of the mash every 15 minutes. If you were using a well insulated vessel it would be even more stable, but with an uninsulated stainless vessel there will always be a bit of variation. Nothing wrong with some stirring, if there were, the pros wouldn't have mash rakes running. Chances are if you did nothing you would still get acceptable results due to the average temps in the main body of the mash.

Offline ckpash88

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Kettle Mashing Question
« Reply #7 on: November 27, 2012, 07:30:21 PM »
Two questions.

Should I have the pump recirculating wort while I am stirring?

Would my best bet on monitoring mash temp be right at the kettle valve? If my thinking it right that should be the hottest area in the mash.


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Offline ckpash88

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Kettle Mashing Question
« Reply #8 on: November 27, 2012, 07:34:00 PM »
I know I didn't mess up my last batch bc the airlock was going crazy. I am just not sure if I hit my target temp to get the right gravity... I guess I'll know after it hits fg.


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Offline dcbc

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Re: Kettle Mashing Question
« Reply #9 on: November 28, 2012, 08:39:35 AM »
Two questions.

Should I have the pump recirculating wort while I am stirring?

Would my best bet on monitoring mash temp be right at the kettle valve? If my thinking it right that should be the hottest area in the mash.


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I think there are multiple schools of thought on probe/thermometer placement.  The valve is probably fine.  Mine is about in the middle of my loop, about 3 feet of silicone hose and one pump from the kettle outlet.  This is about half way between the heat source (direct fired) and the mash liquor return in the kettle.  Once everything settles in, the probe in the loop is reading the same as both the kettle thermometer (mid mash) and the thermometer I can stick in the wort stream at the return or in several spots at the top of the mash.  So, the answer is that it probably doesn't matter too much.  By having it mid stream, I'm chancing that the mash liquor below the false bottom where heat is being applied might be slightly hotter the second or two it's being heated before leaving the mashtun and recirculating across the probe that controls the flame.  But that's not enough of a variation to worry me.  My recirculation rate is pretty quick.  So things are constantly moving.

As for stirring, you shouldn't have to if you are recirculating your mash liquor and you have a return line placed in a way that causes that mash liquor to flow fairly evenly throughout the mash.  The quick paced recirculation of the mash liquor coupled with a low heat source will help you avoid scorching and the correct placement of the return line helps to keep the mash temperature uniform.  By stirring, you are disturbing the mash bed, making it harder for the mash liquor to clear, and could possibly increase the chances of a stuck mash.

This is, of course, based on my system.  So your mileage may vary.

I should also add that my direct fired RIMS is automated.  So I'm not doing anything but letting the mash settle for about 10 minutes, starting my pump, slowly at first, then increasing flow to a pretty brisk rate, then punching in my temperature on the controller, and letting the controller do all of the work.  Manually turning the flame off and on sounds like a lot of work and is probably going to lead to some temp swings.  Once my temperature has settled in, the flame-ons don't tend to last longer than a second or two every 30 seconds to a minute. 

Some good insulation for the kettle might be a better bet until you decide to automate the RIMS.  Some closed cell foam (gym mat) and aluminum tape did just fine for my kettle for an hour mash as long as I wasn't recirculating.  It's not the prettiest thing, but it works.

Good luck.
« Last Edit: November 28, 2012, 09:00:49 AM by dcbc »
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Offline dean_palmer

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Re: Kettle Mashing Question
« Reply #10 on: November 29, 2012, 11:15:44 AM »

Should I have the pump recirculating wort while I am stirring?

Yes

No reason to shut it off when you stir unless what you are doing affects the pumps. Mine work fine when stirring the mash.

As for clearing of the wort, that will happen with a few minutes or less of recirculation, so just don't stir near the end of the process.

There is really no downside to any normal (not excessive) stirring of the mash. In a non-heated setup where you lose heat by opening the lid, stirring and heat loss can be a concern, but for a heated mash system it isn't.

As for the right place to take the temp, there are lots of places you could measure, but what matters is the average temp of the mash itself. Don't obsess, but do take all the tips provided for insulation as that is your best chance to keep an even temp in a metal vessel. Go low-tech like a blanket or removable foam wrap. Don't attach anything, you'll regret it later, trust me, done a lot of ideas there. Just something you add after the mash and recirculation is stable, and something you can remove at the end of the mash session.

Offline AleForce

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Re: Kettle Mashing Question
« Reply #11 on: November 29, 2012, 11:51:41 AM »
What size of tubing are you using for recirculating?  3/8" , 1/2" ?   

When I was using a cooler for my mashtun, I was using 3/8" tubing... When I switched to using Blichmann's I had to go to 1/2" tubing to get a better flow rate coming out of the kettle, which meant the pump wasn't having problems...
 
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Kettle Mashing Question
« Reply #12 on: November 29, 2012, 12:46:01 PM »
What size of tubing are you using for recirculating?  3/8" , 1/2" ?   

When I was using a cooler for my mashtun, I was using 3/8" tubing... When I switched to using Blichmann's I had to go to 1/2" tubing to get a better flow rate coming out of the kettle, which meant the pump wasn't having problems...

Me?  3/8.
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Offline bluesman

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Re: Kettle Mashing Question
« Reply #13 on: November 29, 2012, 08:31:20 PM »
What size of tubing are you using for recirculating?  3/8" , 1/2" ?   

When I was using a cooler for my mashtun, I was using 3/8" tubing... When I switched to using Blichmann's I had to go to 1/2" tubing to get a better flow rate coming out of the kettle, which meant the pump wasn't having problems...

I use 1/2" high-temp silicone for my RIMS.
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Offline ckpash88

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Kettle Mashing Question
« Reply #14 on: November 29, 2012, 08:53:08 PM »
I used 1/2 inch bc I had it sitting around.


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