Acceptable temperature range for overnight mashing?

[Zeno990]

Hello

I just got a cooler bag which I intend to use for overnight mashing. A test showed that the temperature sank from 68 c (154 F) to 48 C (118 F) in 9 hours. I will try to improve this, but I would like to know what is the proper temperature range for this. In other words, what is the max temp I should start with (72 c?) and what is the minimum low temperature I should end with (150 c?).

 

[Vuarra]

I would seriously refrain from going much higher than 68 - 69 C, as you may damage some of the enzymes in the grain. Is there a reason why you are doing an overnight mash?

 

[Zeno990]

I would seriously refrain from going much higher than 68 - 69 C, as you may damage some of the enzymes in the grain. Is there a reason why you are doing an overnight mash?

ok, thanks. The reason to do overnight mashing is to divide the workday. I rarely have the time to do a full brew day, but this way I can get away with a few hours in the morning.

 

[JPicasso]

I've heard of this being done but after your normal 60-90 min mash, the temps are taken up to 170F to stop the process. But it would require transferring the wort to a boil kettle for a time. When you return home from work, or sleep, or whatever, bring the wort back up to boil and finish.

I would not recommend leaving the mash at mash temperatures for 8 hours, or starting the temp on the high side, and letting it slide. I think you'll get unpredictable results and inconsistant beers. Or, you'll lay the groundwork for some new method with fantastic beers. Be sure to post back with results!

 

[theonetrueruss]

I say start at the mash temp you want.. let it go through the night.. sparge, brew, ferment, condition and drink. Then decide how well that works. Probably wind up being a bit dry. I've done mash and sparge in one night then boil etc in the morning with good results though.

 

[JPicasso]

There's a guy posting in the All-Grain forum that is having good success with overnight mashing. I'd suggest checking his posts out. Quite possible that as long as you take into account the results of a 9 hour mash, like drier beers, and adjust, like you mentioned with a higher temp it might be possible to predict the outcomes.

So, I'm giong to encourage you to continue this practice and let us know how it goes!

 

[BigB]

You are fine with leaving it overnight and don't need to worry about it cooling down. As long as you maintain the temp +/- a couple degrees for the first 60 minutes, the rest of the time isn't going to affect your beer... except giving a slight increased risk of infection due to the long period. All conversion of starches is pretty much done in 30 minutes... 60 minutes is done to be safe, and some grain bills need slightly longer time (hence 90 minute mashes). But for the vast majority of beers, after 60 minutes, you have all the conversion you are really going to get.

 

[DeafSmith]

This is an interesting possibility I hadn't considered. I mash in a 10 gallon RubberMaid cooler, but if I used a heatstick to raise the temperature to 170º F at the end of the mash before letting it sit overnight, would that totally denature the enzymes and completely prevent the beer from drying out?

 

[osagedr]

...the rest of the time isn't going to affect your beer... except giving a slight increased risk of infection...

How so, if he's still going to boil his wort?

 

[BigB]

How so, if he's still going to boil his wort?

Good point... brain cramp... I apparently decided to give advice about those that decide to wait a day to pitch their yeast too... LOL

 

[itsme6582]

I say go for it. Try it with a simple recipe and see what happens. Just stick with the same mash temp you'd use for a normal brew day.

 

[ultravista]

Is there a purpose to overnight mashing? Once conversion completes, that's it right?

I don't understand.

 

[Zeno990]

Is there a purpose to overnight mashing? Once conversion completes, that's it right?

I don't understand.

to divide the workday. It would be ideal for me to set a mash in the evening, and then spend a couple of hours in the morning to boil the wort (and put the wort in a no-chill container). I can then transfer to fermenter in the evening.

Quite a few people have done this and it apparently works well. Just search for it on the net.

My main worry is actually the lowest temperature that the mash should have, since it drops 20 degrees C over 9 hours. The problem is that a slight infection might give off flavors (although the infection itself will be stopped in the boiling). I'm guessing that I shouldn't let the mash go below 55 C to avoid infections, which will be a bit tricky with my setup.

 

[BigB]

Completely ignore the infection issues that I may have inappropriately thrown into the mix. The short period of time between the mash and the boil (although it is several hours) won't be long enough for any bug to affect the flavor. Also, don't worry about the temperature drop after 60 minutes. The temp at 2 hours, let alone 9 hours, is irrelevant as the conversion has already long since taken place.

 

[Vuarra]

I agree with the general consensus... it really won't hurt the beer. If it makes your day easier... go for it!

 

[tonyolympia]

I hate to resurrect an aging thread...but what about a mashout step?

Doing a 60 minute mash and having to sit around to raise it back to 170 before you go to bed would remove the set-it-and-forget-it aspect that makes an overnight mash attractive, but you'd still shorten your brew day.

But is it necessary to denature the enzymes at all? Or could the mashout be skipped? If you do mashout, is there any risk to raising the wort to 170 and letting it slide overnight? I can't think of any. But would it be better to mash, mashout, and sparge the night before and begin the next day with the boil?

I'm doing BIAB, by the way, and holding mash temps in a preheated oven. I know I could do a no-sparge mash, but I'm not yet comfortable letting my mash get any thinner than 1.75 qt/lb. Maybe someday.

Any thoughts on mashout and overnight mashing for BIAB would be appreciated.

 

[osagedr]

I think a lot of people skip mashout with no ill effects.

The best brewer I know personally does overnight mashing.