Big variations in Mash Temp

[i4ourgot]

I am getting some big variations in my mash temps, even after letting it sit for 10 min. One part of my mashtun is reading 160 one part 140 and one part is reading 150. even after stirring and letting sit for 15 min I am getting this variation in readings.

 

[Cyclman]

Mash vessel?

 

[dmtaylor]

That's normal. It doesn't matter. The only thing that really matters is the overall average.

 

[Bigdaddyale]

Freaks you out doesn't? Increase your qt./lb ratio to 1.50 /1

 

[RM-MN]

When your mash tun gives you those kind of variations over the short time there are a couple solutions. First is to change the environment. Mash indoors to keep the temperature difference from the mash to outside tun smaller and no wind to chill it or increase the insulation of the tun is one. The second is to change the mash period. It doesn't take an hour for the conversion to happen, it takes minutes. What takes time is the gelatinization of the starches so conversion can start. That time it controlled by the size of the grain particles. If you mill the grain very fine, the conversion is done before the temperature drops enough to matter but then you have to worry about a stuck mash or sparge....unless you use something like a fine mesh bag to do the filtering. Line your mash tun with Swiss Voille (curtain material, readily available) and make it form a bag when the mash is done and you can lift it up a bit to form a huge filter area. No stuck mash or sparge!

 

[i4ourgot]

So that temperature variation is normal even at mash out I had pretty big variation in temperature on a 75 min mash. I though I would have pretty good insulation because its an insulated water cooler that i'm using but my mash definitely has more cool spots on the outside of the mash tun ( although the middle wasn't the warmest). I'll try more water but I heard more water means that conversion takes longer, not sure if this is true. Something about the enzymes have to travel further to the carbohydrates. Again not sure if that is true or not.

 

[Staticsouls]

The real solution is to obtain a pump and recirculate your mash. Preferably through a heat exchanger in your hlt or kettle to help maintain stable mash temps.

 

[schematix]

That's normal. It doesn't matter. The only thing that really matters is the overall average.

^^^this is ranks among some of the worst advice i've ever seen on HBT. do not listen to this. mash temperature matters a lot, especially in the range OP is mentioning.

temp stratification happens. its going to be especially pronounced in a small mash vessel.

stir more or recirculate.

 

[kevin58]

Stir.

 

[Qhrumphf]

The best way to get consistent mash temp is a grist hydrator or otherwise adding grain and mash liquor simultaneously so that everything is consistently mixed and at the right water to grain ratio and temp from the start. This is difficult to do with homebrew gear/scale (though not impossible, but perhaps not practical). Assuming normal process of adding grain to the full volume of strike water, stir the f*** out of it while adding grain at a slowish metered pace, and then stir more when you're done.

 

[RM-MN]

The real solution is to obtain a pump and recirculate your mash. Preferably through a heat exchanger in your hlt or kettle to help maintain stable mash temps.

I'd say this is the expensive way to maintain the temperature for the conversion. Milling the grain finer so the starches gelatinize quicker and convert before the temperature changes is much cheaper. A 60 minute mash with super temperature control isn't necessary if the conversion is done in 5 minutes.

 

[wilserbrewer]

Stir more.
I only take temps after stirring, resulting in the average temperature.

Of course after sitting for 15 minutes the outer edge against the kettle will be cooler, but I don’t worry much about it...

My opinion, recirculating is a wonderful thing, but can lead to more difficulties for not much quantifiable improvement.

Stirring is so much easier and cheaper, less stress makes an easy decision for me that recirculating is not worth the added effort and equipment. Jmo

 

[dmtaylor]

^^^this is ranks among some of the worst advice i've ever seen on HBT. do not listen to this. mash temperature matters a lot, especially in the range OP is mentioning.

temp stratification happens. its going to be especially pronounced in a small mash vessel.

stir more or recirculate.

Your reaction is a little extreme. I stand by my previous statement.

If you're going to stir a lot, be aware that everytime you open the mash tun and stir, you're going to lose a few degrees. Temperature at the highest point might fall to 140s or even low 130s if you overreact, and then you might wish you hadn't touched it.

Have a nice day.

 

[schematix]

Your reaction is a little extreme. I stand by my previous statement.

If you're going to stir a lot, be aware that everytime you open the mash tun and stir, you're going to lose a few degrees. Temperature at the highest point might fall to 140s or even low 130s if you overreact, and then you might wish you hadn't touched it.

Have a nice day.

I stand by my statement that you are offering advice which is so poor it's not regularly encountered here on HBT.

You've doubled down by offering additional bad advice - which is that stirring causes the loss of several degrees. Maybe if you're mashing in a 100mL beaker, but for a mash containing 10lbs of grain and 30lbs of water (very realistic for a 5 gallon batch), you have so much thermal mass that a little stirring will have little impact on its average temperature, aside from evening it out.

If you are cooler mashing without recirculating you should be stirring at least once every 15 minutes to reduce temperature stratification. When i cooler mashed back in the dark ages i bought a thermometer with a 24" probe. it was quite enlightening to see how in-homogeneous a mash was and how quickly it stratified. Once i switched to a recirculating mash i used the same probe to confirm how stable the temp was.

 

[wilserbrewer]

My guess is the OP is not stirring enough at dough in.

Try stirring for at least two minutes at dough in, wait about 5 minutes then stir for another two minutes.

Keep stirring until you get readings throughout the mash that only differ by a degree or two.

Getting temps ranging from 140-160 is very unusual imo and is more than cooling and stratification?

My guess is that you never achieved a good thermal mix???

 

[Bigdaddyale]

Did the OP ever state his grain to water ratio? I got a feeling he was making cement

 

[Bigdaddyale]

That said- what is your grain to water ratio?
Batch Sparge, 5 gallon , 1.50

 

[augiedoggy]

I use a rims for this. some use a herms and some use a well insulated mash tun. if you preheat the mashtun and stir well when doughing in you shouldnt get such huge shifts unless like others stated your brewing out in an arctic wind storm or using a non insulated mash tun.

 

[i4ourgot]

That said- what is your grain to water ratio?
Batch Sparge, 5 gallon , 1.50

It is viscous enough for my thermometer to keep falling over when i stick it in the middle of the mash tun. I would add 200F water to my mash tun (about 1 gallon to half a gallon) than add grain and stir and keep repeating. Not sure what I do for a grain to water ration I add water aiming for a certain temperature. Sometimes adding cold water to bring my temps down because I can't heat my mash in my mash tun, and I don't have a pump. before I closed my mash tun I stirred for 4-5 min trying to make sure I didn't have any dough balls. Out the lid on with my thermometer and checked 5 min later. I was getting pretty different readings so I stirred my mash again for a few min while checking my temps, and was still getting pretty different readings.

 

[Bigdaddyale]

It is viscous enough for my thermometer to keep falling over when i stick it in the middle of the mash tun. I would add 200F water to my mash tun (about 1 gallon to half a gallon) than add grain and stir and keep repeating. Not sure what I do for a grain to water ration I add water aiming for a certain temperature. Sometimes adding cold water to bring my temps down because I can't heat my mash in my mash tun, and I don't have a pump. before I closed my mash tun I stirred for 4-5 min trying to make sure I didn't have any dough balls. Out the lid on with my thermometer and checked 5 min later. I was getting pretty different readings so I stirred my mash again for a few min while checking my temps, and was still getting pretty different readings.

I used this page to calculate my mash tuns thermal mass.Once you know that its pretty easy to hit tempts. http://jansson.us/mashcalculator.html

 

[i4ourgot]

cool thanks thats really helpful.