Mash Temp

[WaltG]

OK, so getting ready to do a 1 gallon biab. What I'm wondering is how close do I have to stay to the mash temp? I mean if the mash temp is 152deg am I ok staying +/- 5 degrees or do I need to work to keep it closer?

I know if I strike temp at about 12 degrees above and just wrap the kettle in a blanket I wont get below about 148-149.

 

[QuercusMax]

Set your oven to its lowest setting (I put mine on Warm) and put your mash vessel in the oven. Should keep the temperature perfectly.

 

[3PegBrew]

Set your oven to its lowest setting (I put mine on Warm) and put your mash vessel in the oven. Should keep the temperature perfectly.

In all the years of doing stove top brewing...I never once considered this. Wow!

 

[NervousDad]

I have a built in temp probe in my oven I've been temped to mash so many times, but I always get too lazy

 

[stpug]

In terms of full conversion, +-5 degrees with a center temp of 152 is fine. You'll get full conversion of the starches provided you give it enough time. If you fall down to 147 quickly then you'll want to give some extra time; if you jump up to 157 quickly than you might want to cut your time short a little bit. All in all, you'll get conversion at that temp +-5F given an appropriate amount of conversion time.

HOWEVER, I have found that PEGGING a specific mash temp is the single best way to ensure your FG and ensure you'll get the malt/body profile you'd expect from certain mash temperatures. I had several batches suffer the slow temp fall (152ish falling to 148ish) and those beers overattenuated; finished lower than expected; had less body than I'd hoped for; and, put simply, were mildly unbalanced. They were certainly drinkable and even pretty good, but did not meet my expectation for what I had planned. So, having the ability to really peg your mash temperature is KEY to having a beer finish where and how you expect it to.

The preheated low-setting oven is perfect for 1 gallon batches. Hit your mash temp, put in a 170F oven, and you should be sitting wonderfully after 45-60 minutes. The warmer air will act as an insulator and not affect the actual mash temperature too much. I like to turn off my preheated over about 10 minutes after putting the MLT/pot in there.

At the end of your mash, in order to get a good read on your final mash temperature, you really need to stir it up well and then check the mash temp. I have found that this will give you the best reading for your final mash temperature.

 

[dangerbrew]

I'd say you don't even have to go the oven route, really - I'd just estimate for a degree or two above where you want to end up for your target and then throw about 2 towels over the kettle to hold the temp. Also, remember to get in there and stir that thing every 15-20 minutes or so. Brewers tend to forget to do this sometimes, but hot and cold pockets develop in the mash, and just by stirring you can distribute the temperature throughout and make sure you get a good conversion.

I know sometimes I'll be doing a mash and my thermometer will read a little lower than I expect, and then I'll take the lid off and stir it and it will go back up a few degrees at least, evenly distributing the warmth.

Hope this helps.

 

[PRE66_6TART]

Stirring my mash frequently is exactly what led to me having problems maintaining my mash temps. Every time I took the lid off and stirred the temp would start dropping, then I'd try to add heat and I'd have to stir it more to evenly distribute and the temps would start bouncing around like crazy. I think just getting it to the right temp and sticking it in the oven and leaving it alone is a better way to go. I start off a few degrees too high and stir like crazy until the temp comes down to where I want it, that way I know it's thoroughly mixed, then I cover it, pop it in the pre-warmed oven, turn the oven off, and don't touch it until it's done. Smaller mashes with less thermal mass lose heat easier so people doing large mashes in ten gallon pots are a different story.

I think the OP mentioned a strike temp of +12 degrees. That sounds high for a one gallon batch. That's about what I do for five gallon batches.

 

[QuercusMax]

I think the OP mentioned a strike temp of +12 degrees. That sounds high for a one gallon batch. That's about what I do for five gallon batches.

If you preheat your mash tun, then your strike temperature shouldn't really vary based on the size of your batch.

 

[PRE66_6TART]

If you preheat your mash tun, then your strike temperature shouldn't really vary based on the size of your batch.

I've never done a one gallon batch, but it seemed like two pounds of grain wouldn't lower the temp as much as 10 pounds. I guess it's the water/grain ratio that matters though. That makes sense.

 

[dangerbrew]

I've never done a one gallon batch, but it seemed like two pounds of grain wouldn't lower the temp as much as 10 pounds. I guess it's the water/grain ratio that matters though. That makes sense.

The water/grain ratio is what matters. Papazian says to go with 1 quart to 1 lb of grain for your mash and you'll get a temp drop of between 16-18 degrees when adding the grains. I always presuppose it will be 18 and add cool water to balance it out if needed. If you have a ratio like this then the thermal mass should be stable enough that you wouldn't need to worry about the temp falling down like crazy by removing the lid and stirring about 3 times during your mash to equalize the temps throughout the mash.

 

[PRE66_6TART]

The water/grain ratio is what matters. Papazian says to go with 1 quart to 1 lb of grain for your mash and you'll get a temp drop of between 16-18 degrees when adding the grains. I always presuppose it will be 18 and add cool water to balance it out if needed. If you have a ratio like this then the thermal mass should be stable enough that you wouldn't need to worry about the temp falling down like crazy by removing the lid and stirring about 3 times during your mash to equalize the temps throughout the mash.

That was just my experience with my setup. My five gallon pot that I mash in is pretty short and wide (that's why it fits in my oven), and I'm not sure what material it's made of but it doesn't seem to hold heat very well. So trying to keep it from losing heat was an uphill battle for me, and taking the lid off and stirring wasn't helping. I also might have been stirring too much or something. I just know that I had a hell of a time keeping it steady until I started leaving it in a warm oven and not messing with it. Everyone should figure out what works best for them though.

I did notice the temps being inconsistent throughout the mash before I started using the oven. I assumed it was due to heat escaping at the top and sides of the pot, but it doesn't seem to be a problem in the oven, for me anyway.

Anyway, that's all I got.

 

[dangerbrew]

That was just my experience with my setup. My five gallon pot that I mash in is pretty short and wide (that's why it fits in my oven), and I'm not sure what material it's made of but it doesn't seem to hold heat very well. So trying to keep it from losing heat was an uphill battle for me, and taking the lid off and stirring wasn't helping. I also might have been stirring too much or something. I just know that I had a hell of a time keeping it steady until I started leaving it in a warm oven and not messing with it. Everyone should figure out what works best for them though.

I did notice the temps being inconsistent throughout the mash before I started using the oven. I assumed it was due to heat escaping at the top and sides of the pot, but it doesn't seem to be a problem in the oven, for me anyway.

Anyway, that's all I got.

From gwk435 over at The Brewing Network forums:

"You have to determine what the max. grain weight you can mash, having the grain covered with a couple of inches of water and still have the ability to stir it without having to mop the floor. It is a real number which you can't exceed or else your mash will resemble cooked rice with your shoes covered with mash. If you can't manage your mash consistency and temperature by stirring, you will have hot spots and clumps. It doesn't matter what you stir it with, you should be able to feel any clumps with your spoon, etc., if you brew often enough. I have even used the long green Blichmann brewing gloves to dive into the mash. Adding grain to strike water works better than the other way around. So you will need know your max. strike volume, too. If you recirculate, more water is a must.

Know your limits, and boost your gravity with DME or suitable sugar in the boil if you need more gravity.
Think less grain .....more water..... room to stir"