Maintaining Mash Temp

[SamInNJ]

I did my first full volume BIAB batch this past weekend. (Just switched from extract). (was about 7.25 gallons in an 11 gal SS Bayou pot).

When I added my grains I hit my target mash temp (152). A friend and I removed the kettle from the heat and placed / wrapped in a sleeping bag. I came back once a half hour or so in to stir the mash. At 60 minutes we noticed the temp had dropped to 148.

Is this drop concerning? I had assumed the sleeping bag and the thermal mass would have allowed everything to stay a bit more consistent over a 60 minute mash.

Largely my attitude on this is :RDWHAHB, hit my target gravity etc. Just want to know how I can improve my process for the future and dial in my mash temp control a bit better.

 

[Johow]

Sounds like you did good!

 

[SamInNJ]

is a 4 degree loss in mash temp over an hour standard/normal?

 

[dmtaylor]

4 degrees ain't nothing. Yes, it's totally normal to lose that much. Worry only if it loses 8 or 10 degrees. You did great.

 

[SamInNJ]

awesome! Thanks! Hit target gravity and volume into fermentor. Pitched 1L starter. It's fermenting like crazy. Will post how it turns out!

 

[McKnuckle]

As others said, that's not a bad drop. You could avoid stirring until you pull the bag if you want to conserve another degree or two of heat. Stirring in the middle of the mash gives us a reassuring feeling but isn't really necessary, provided you make up for it at the end.

Congrats!

 

[SamInNJ]

What do you mean by "make up for it at the end?"

Get the grains in, stir, insulate. Wait 60-90, then just stir a ton before bringing the bag out?


I guess, in a nutshell is stirring during the mash not necessary?

 

[MatchstickBrewingCo.]

I brewed over the weekend and hit my mash temp range (154) and did the same as the OP, wrapped in a blanket and a sleeping bag. But since it was below freezing temps I still dropped to about 145 throughout the 60 min mash. Still hit an OG of what I was expecting but should I expect any ill effects from the temp drop? Fermentation seems to be going fine but I'm not sure what to expect.

 

[ballsy]

Keep in mind, temperature equilibrium b/w grain and the water actually takes a couple minutes to happen after stirring the grain in so if you stirred in and took immediate temp then sealed it up, it might have dropped anther couple degrees just b/c the grain and water hadn't totally equalized yet. Either way 4 deg's is no big deal, and depending on how fine you mill your grain the conversion could have completed before your temp even dropped more than 1 or 2 degrees. I now put my 10gal pot in then oven (set at 150 deg) and turn off the oven about 30 min into the mash and it keeps stable temp the whole time even with stirring every 20 minutes.

 

[ballsy]

I brewed over the weekend and hit my mash temp range (154) and did the same as the OP, wrapped in a blanket and a sleeping bag. But since it was below freezing temps I still dropped to about 145 throughout the 60 min mash. Still hit an OG of what I was expecting but should I expect any ill effects from the temp drop? Fermentation seems to be going fine but I'm not sure what to expect.

Worse case is it finishes slightly drier than it should have but means higher ABV:rockin: If you brewed an IPA, pale ale, blonde, etc...then it would work well with it. Main types you don't want to be as dry (low finishing FG...) are styles like stouts, porters, etc...

 

[MatchstickBrewingCo.]

Ok good, I brewed an IPA and its got a little bit of wheat malt, honey malt, flaked oats, and flaked barley so the mouthfeel should still be there as well. Thanks for putting my mind at ease Ballsy

 

[wilserbrewer]

By "make up for it at the end" I believe he means to stir thoroughly prior to removing the bag.

I wouldn't sweat 4 degree loss. I would suggest perhaps mashing a couple degrees higher anticipating the drop.

So instead of targeting 152, mash to hit 154 and knowingly let it drop to 150.

Think of mashing as a range, and not an exact temp. This will help to balance your temp loss.

 

[iijakii]

I'd first see what the temp loss is like at 30 mins. 4F is fine on its own. If that's somewhat linear and youre only at 2F 30mins in, great. I wouldnt mash higher to offset that if so. But couple degree swings won't make one difference anyways, so whatever.

 

[tennesseean_87]

Keep in mind, temperature equilibrium b/w grain and the water actually takes a couple minutes to happen after stirring the grain in so if you stirred in and took immediate temp then sealed it up, it might have dropped anther couple degrees just b/c the grain and water hadn't totally equalized yet. Either way 4 deg's is no big deal, and depending on how fine you mill your grain the conversion could have completed before your temp even dropped more than 1 or 2 degrees. I now put my 10gal pot in then oven (set at 150 deg) and turn off the oven about 30 min into the mash and it keeps stable temp the whole time even with stirring every 20 minutes.

But conversion is not a once and done sort of deal. You can have conversion from starch finished but still be chopping up the longer chains into shorter chains. This is why fly spargers do a mashout--they might complete conversion in the mash, but the longer it sits while slowly sparging the more fermentables are created if the enzymes are not first denatured.

That said, I think OP's probably fine. I was also going to mention mashing a little higher to compensate, but maybe compare some recipes with the FGs you are getting with the temp loss. If your FG always seems lower than expected with the same yeast, compensate by mashing a few degrees higher than recipes indicate. If it still finishes around the right gravity even with the temp loss, don't worry about it.

 

[ballsy]

But conversion is not a once and done sort of deal. You can have conversion from starch finished but still be chopping up the longer chains into shorter chains. This is why fly spargers do a mashout--they might complete conversion in the mash, but the longer it sits while slowly sparging the more fermentables are created if the enzymes are not first denatured.

True, but I can't help but think out of the majority of chains already extracted at full conversion, there is a minimal percentage chopped up shorter thereafter. Plus this is the BIAB forum, we aren't supposed to talk about crazy things like sparging hahaha. You have a good point though. But like all have said, I'm sure the OP's batch will be fine.

 

[RM-MN]

True, but I can't help but think out of the majority of chains already extracted at full conversion, there is a minimal percentage chopped up shorter thereafter. Plus this is the BIAB forum, we aren't supposed to talk about crazy things like sparging hahaha. You have a good point though. But like all have said, I'm sure the OP's batch will be fine.

You might be surprised how many of us crazies that sparge even with BIAB are around. It works really well for making up volume when your pot is just a little to small for full volume BIAB plus it collects more sugars from the wort.

 

[ballsy]

You might be surprised how many of us crazies that sparge even with BIAB are around. It works really well for making up volume when your pot is just a little to small for full volume BIAB plus it collects more sugars from the wort.

Oh, trust me I pour 2 gallons of sparge water over my bag every time too! I was just joking around b/c I've read the argument many times on here over the years that's all

 

[Jim311]

I'd say most of the conversion takes place in the first 15 minutes anyway so that drop in temperature is completely negligible. As far as "sparging" I just dunk the bank in some 170 degree water I'm bringing up to a boil. I stir the bag around for a few seconds, then pull it out. It helps my efficiency some by extracting some extra sugars I think.