preheat cooler or compensate strike temp?

How many of you guys are getting away with using a elevated strike temp to compensate for cooler absorbtion?

The first thing I did was put 3 gallons of boiling water into my rectangular cooler and let it sit for a while. This really deformed the cooler in some spots so I'm thinking it is a bad long term solution.

Even after the preheat, adding 12 qts of 166dF water to 10lbs of 70dF grain brought my temp to a stable 143 when I was shooting for a 154dF mash (these instructions were per brewsmith). What the hell went wrong? My cooler is a bit large, I'd say the headspace was equal to the grain + water space so it was half full. Does this effect it?

Should I just try striking at like 195 without the preheat next time just to see where I stand? Maybe I'll go with 1qt/lb at first and leave that last .25 qt/lb for temp adjustment.

According to this calculator that I've had good results with...

http://www.rackers.org/calcs.shtml

You need a strike temp of more like 170 to hit 154 with that mash.



I usually just heat the water to about 180-185, pour it in the cooler, and wait for it to settle to the desired strike temp. I've had good luck with that procedure, which is quicker and more efficient than pre-heating with seperate water.

Well I always preheat with just warm water. How long did you wait before checking the temperature? I have noticed with thick(er) mashes like that it takes a few good, deep stirs and then at least 5 minutes to let it stabilize. My reading is always low off the bat with thick mashes.

Yeah, so I wonder why Brewsmith steered me wrong. Hmm, maybe I told it I had a much smaller cooler in the equipment setup. Shouldn't matter that much. I actually have a probe thermo so I was monitoring the temp constantly. It stuck at about 145 even after a few stirs and 5 minutes of waiting. I added 1 qt of boiling water and it got me to 153 so I stayed there.

I guess I'm lucky.

My first guess was 170 for 154 and it was right always hit within 1f or so.

I do both. I don't however add boiling water. I spray in the hottest tap water I can into the tun. I over shoot the strike by about 4 or 5 degrees and mash in when it's spot on. I've had pretty good luck with this method.

Since my brewery is an unheated garage, the tun can be anywhere from 30F-105F. Pre-heating the cooler removes a possible complication. In warmer weather the 'add & wait for the strike temperature' method works, but in the winter I end up draining the cooler & re-heating the water. As long as the cooler is closed, I don't lose too much of the pre-heat.

david_42 said:

Since my brewery is an unheated garage, the tun can be anywhere from 30F-105F. Pre-heating the cooler removes a possible complication. In warmer weather the 'add & wait for the strike temperature' method works, but in the winter I end up draining the cooler & re-heating the water. As long as the cooler is closed, I don't lose too much of the pre-heat.

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I'm a AG n00b (still collecting equipment) but I surely will fall into this temperature swing camp, but my temp swing will be close to 30F to 140F. Are we all assuming room temp grains? I imagine that there could be 10-15°F variation in that, or I am I overthinking?

Bobby_M said:

Yeah, so I wonder why Brewsmith steered me wrong. Hmm, maybe I told it I had a much smaller cooler in the equipment setup. Shouldn't matter that much. I actually have a probe thermo so I was monitoring the temp constantly. It stuck at about 145 even after a few stirs and 5 minutes of waiting. I added 1 qt of boiling water and it got me to 153 so I stayed there.

Click to expand...

Hmm, yeah the cooler size shouldn't really matter at all. The equations are dependent on grain temp, water amount and grain amount. The biggest varying factor is the temperature of your grain for sure. I always, always measure it just before mashing.

Well I'm sure the dry grain temp has quite an impact on the settling temp of the mash, at least as much as the cooler wall temp. I'd say bringing the cooler into your living space overnight would take some of the burden off.

Just posted a thread, I'm doing my first AG right now. Hit 154 on the nose pretty much with 172deg strike water.

seefresh said:

Just posted a thread, I'm doing my first AG right now. Hit 154 on the nose pretty much with 172deg strike water.

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With or without preheating your MLT?

I put 172 degree water in my cooler, then I added the grains and stirred.

I preheat my cooler too with 170 degree water. I don't add boiling water as that may damage the water cooler.

170 degree strike works out every time and the temp does not move a degree for the 60 to 90 minute mash time.

Bobby_M said:

I actually have a probe thermo so I was monitoring the temp constantly.

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Are you sure your probe thermo is correct? What kind are you using? Is it one of those intended for use in the oven like you can get at Target, etc?

I haven't had much luck with the one I have. In my case it seemed to start out at the correct temp, but at the end of an hour it said my mash temp had dropped 15°F. When I checked it with my other thermo I had only lost a couple degrees. I know it's a different situation, but something to consider.

SP

Yes it's the oven type with the probe and stainless braid over the wire but i've protected the first 2 feet of the wire with silicone tubing filled with keg lube. I used a #60 O-ring underneath where it attaches over the probe. Completely water tight and working like a charm. I did verify that it was spot on with my candy thermo. In fact, i move the probe over to my brew pot and it was reading 210 at vigorous boil which is almost correct at my altitude.

I have a 7 gallon Rubbermaid mashtun and I preheat with hot water out of the house (about 4.5 gallons). It's 130F and I let it sit for about 30 minutes while I heat up the strike water - I dump the water and go in at around 167F and work for that 153-154F target. So far, so good.

I heat my strike water to 185 F and drain into my 48 qt cooler/mash tun, the cooler absorbs 5 to 10 degree's instantly, depending on the amount of water. I then just wait until I reach my mash in temp, I rarely miss my mash temps and can maintain temp quite well. Of course when its 5 below I have to wrap the cooler with an electric blanket, a sleeping bag and a chunk of foam rubber on top.

For mini-mashers out there, I hit my temp perfectly by pre-heating w/ tap water and using water 11 deg over target per the BYO article on using a 2-gal cooler (4 lb grains).