Author Topic: Mash temperature differences  (Read 3725 times)

Offline speed

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Re: Mash temperature differences
« Reply #30 on: February 23, 2010, 08:03:25 PM »
instead of slowly stirring, i take my spoon in one end of the tun and make small rapid circles. it will move the grain across the whole length of the cooler. i feel that evens out the temps more.

Offline bspisak

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Re: Mash temperature differences
« Reply #31 on: February 24, 2010, 12:12:02 AM »

I'm interested in a motorized mixer simply because I'm lazy. ;)

If you are doing multi-step decoctions, there's a whole lot of stirring to do. It takes at least 5 minutes of continous stirring to get temp gradients minimized (longer for stiff mashes.)

Also, Its hard to avoid aeration when using a spoon or paddle to stir with: one has to lift and fold the mash to evenly mix.

If you're using a direct fired tun, it's hard to keep the grain from scorching. A properly designed mixer can get the mash off the bottom of the tun.

An evenly heated mash can also help repeatability batch to batch.

Anyway, this article is a good read:

http://brewingtechniques.com/library/backissues/issue2.6/put.html
   

Offline stout_fan

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Re: Mash temperature differences
« Reply #32 on: February 24, 2010, 07:28:11 AM »
... I get about 75 to 78 percent with this tun. ...

What you need to do is do a batch of a recipe that you know the efficiency of with the blades off and see if it makes a difference.
I'd say something witty down here, but I'm at a bit of a disadvantage in that department.

Offline beerocd

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Re: Mash temperature differences
« Reply #33 on: February 24, 2010, 07:43:06 AM »
Stirring VS Recirculating? Is one better? I think the motors vs pumps and the effort required are probably equal. So does anyone see a definite benefit of one over the other?
The moral majority, is neither.

Offline dhacker

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Re: Mash temperature differences
« Reply #34 on: February 24, 2010, 09:15:25 AM »
Stirring VS Recirculating? Is one better? I think the motors vs pumps and the effort required are probably equal. So does anyone see a definite benefit of one over the other?

The breaking of any clumped dough balls is better handled by stirring . . .
Just brew it...

Offline bspisak

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Re: Mash temperature differences
« Reply #35 on: February 24, 2010, 09:28:29 PM »
Stirring VS Recirculating? Is one better? I think the motors vs pumps and the effort required are probably equal. So does anyone see a definite benefit of one over the other?

The biggest difference is that stirring alone doesn't allow you to adjust your mash temp. A recirc system usually runs through a heat exchanger. Stirring might in fact benefit a recirc system, though I would think if you have a good tun design, the grain is evenly rinsed by the recirc water, so it shouldn't be necessary.

My stirring setup will be used with a steam infusion system. I decided to go with steam after I saw a recirculation system in action. I wasn't impressed by the temperature fluctuations during recirc: The wort sitting in the plumbing cools when the mash is at temp (and it's not circulating), then the temp in the tun drops a few degrees when it kicks back in. Is that really an issue? Probably not, but add to that all the plumbing required and I decided to go a different direction.

With steam, I can get a pretty good temp rise, on the order of a couple of degrees a minute. Not sure what those RIMS/HERMS folks are getting, but from what I saw of the system I was on, it was much slower. Also, I wonder if those enzymes trapped in the plumbing aren't better off in the mash. For larger batch sizes, the amount of liquid in the plumbing is probably negligible. But, for 5 gallon stiff mashes?

Then there's cost: those pumps are expensive. You can get a windshield wiper motor to drive your mash mixer for $15. (But, I suppose if you've got a pump anyway....)  And you need two temp controllers and stainless fittings for your plumbing.

I dunno, it's probably more a philosophical debate than a technical one. Once you get any system dialed in, you can achieve great results.

Brian

Offline dhacker

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Re: Mash temperature differences
« Reply #36 on: February 25, 2010, 06:07:30 AM »
Brian,

You and I are thinking alike . . keep the wort in the tun where it belongs during the mash! Hence my new tun with a heat exchange manifold inside the tun on the bottom. How are you generating your steam?
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Offline bspisak

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Re: Mash temperature differences
« Reply #37 on: February 25, 2010, 03:47:06 PM »
How are you generating your steam?

Nothing fancy: a cheap second hand presto pressure cooker. It's not too big, I believe it's a 5 qt model. I was concerned it might not be enough, but I fire it on my big burner and it works just fine. I recently did a mash that required 4 injections with steam (doughin to 120s to 140s to 150s to mashout) and it didn't need refilling. That was a 5 gallon mash.

I used soft 1/4" copper tubing to create a ring shaped manifold with perhaps a dozen 1/16" holes drilled in the top. That goes in the bottom of the tun and connects to a fitting I installed on the pressure cooker with a valve to turn the steam on or off. I didn't even bother with high temp tubing: just bought the only stuff the local HW store had that was rated to 170. I sometimes stays pinched once it cools from the lid closing on it, but I have always got it open and have used it a dozen times now without needing to replace it.

The only thing I need to change is that valve I use for controlling the steam. It gets really hot on top of the pressure cooker and is getting hard to open and close. It's probably not rated to those temps.

Overall, I'm quite happy with this setup. It let's me use a cooler to maintain mash temps and then inject steam to adjust or raise as needed. Even with a single step mash, I can now do a mash out and I haven't got a stuck sparge since. The cost and fab is a fraction of a recirc system as well.

Check out this article:

http://www.brewingtechniques.com/library/backissues/issue2.4/jones.html

Cheers!
Brian

Offline euge

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Re: Mash temperature differences
« Reply #38 on: February 25, 2010, 11:07:59 PM »
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Offline dhacker

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Re: Mash temperature differences
« Reply #39 on: February 26, 2010, 05:59:21 AM »
Thanks for those links, euge . . That is perfect!
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