Overnight Mash

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Enhoffer-Knopfe

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Are there any drawbacks from mashing at night, leave it in the mash tun (10 gallon cooler mash tun) overnight then sparge in the morning? I'm attempting to brew 3-5 gallon all grain batches in 1 day. Kids' skating lesson screws with my timing.
 

pompeiisneaks

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I used to think this could be problematic, due to the fact that tannins can be extracted, but now I think that only happens over 170degF, but not sure at this point... How would you keep the mash at temp? I'm not sure it would be great to try and mash out after the mash had cooled down to room temps (or near it) overnite. But I'm fairly new to this and am mostly guessing... I kinda feel like it wouldn't be a good idea... On the other hand, I think if you did the 1 hr mash, and mashout and had the wort ready to boil, and covered that up for the nite, and then did the boil the next day, that may work... but again... don't count on this as being gospel in any way :)
 

TexLaw

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It's been done . . . many times. Often, you get something that's a little "weird" in the final product. I put that in quotes because none of us have ever been able to put a finger on what that "weird" thing is. It's very, very subtle, though. We have wondered if it is not a little bit of souring from bacteria or wild yeast, but there is so little of it. If you keep the lid closed after mashing in, sanitation should not be a major concern (beyond this little "weird" thing).

Also, you better be brewing a beer that you want fairly low on dextrines.

ETA: The tannins that Pompeii mentioned also could be that little "weird" something. One of these days, we'll figure it out, but overnight mashes are too rare.


TL
 

bluehouse

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How long does your mash tun hold temperature for? Have you experimented with this?
 

springer

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I would think that the wild yeast on the grain would start working on the sugar in the wort if left overnight. Since you dont kill it with mash temps but do when you boil it.
 

humann_brewing

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How long does your mash tun hold temperature for? Have you experimented with this?
During the winter and if mashing outdoors would probably not end well, but during summer, my poorly insulated garage would probably stay close to 100 overnight on those nights where it doesn't get below 85 outside.

That that is just one issue, you have the issue of just having it in there for that long period which TexLaw mentioned and make sure you want a beer with a lot of dextrines.
 

ghack

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David Line in his early tome on homebrewing "The Big Book Of Brewing" advocated the use of the overnight mash. I have not tried it.

Barley husks have naturally occurring lactobacillus in them. I've made a small "soured" wort to add to stouts by dropping a handful of crushed grain in a small bit of wort. A few days and it was had a clean nice sour taste.

Sitting overnight, at the perfect temperature for bacteria and some of those lactobacillus or other baddy might start to kick in, but I suspect it would not be to a noticeable degree. I'd boil the mash water to kill anything in it, and sanitize your mash tun and equipment.

Give it a try and let us know.
 

bluehouse

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After the temp drops below 140% you have approx 2 hours before spoilage of the grain & wort starts. So if you maintain temp of 1405 till 4 AM & it starts falling off & you get up and handle the brew before 6AM you have avoided any loss in potential. The longer the tun sits below 140% the greater the potential spoilage and/or loss would be.
 

conpewter

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I was just reading up on what temps kill lactobacillus and came across this
http://jds.fass.org/cgi/reprint/36/4/409.pdf

This is for cheese so they actually want to keep the lacto alive. Basicallly by looking at the charts a rest of 150* for 60 minutes killed all 60 different cultures of lacto. But it did take the full 60 to kill the 2 most heat resistant varieties they were testing. Now was this the type that sours beer? No idea.
 

conpewter

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After the temp drops below 140% you have approx 2 hours before spoilage of the grain & wort starts. So if you maintain temp of 1405 till 4 AM & it starts falling off & you get up and handle the brew before 6AM you have avoided any loss in potential. The longer the tun sits below 140% the greater the potential spoilage and/or loss would be.
My cooler mash tun doesn't even drop 1 degree in an hour, especially if I do a 10 gallon batch ( so it is almost full). I think if you mashed at 150 not only would you kill a lot of the lacto to start with, but it wouldn't get to 140 for 10 hours, plenty of time to wake up on a Saturday and start brewing ;)

I've not tried an overnight mash yet, a lot of my styles have too much body to try doing it.
 

the_bird

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I might be worried about overattenuation with a super-long mash, especially if your target mash temp is on the low side. I've dried out beers by mashing for 90 minutes instead of 60, if all of your enzymes are not denatured it seems likely that you could end up with a slightly more-attenuated product if you mashed overnight.
 
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Enhoffer-Knopfe

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I might give it a try and see what happens. I plan on brewing a Pils, Hefe-Weis and an IPA. Any suggestions on which one might handle an overnight mash better?
 

Octavius

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I used to do this all the time, ie

Day 1: mash
Day 2: mash out, sparge, boil and leave overnight to cool
Day 3: pour into fermentor and add yeast

The advantage, of course, is that you do not have to spend a whole day brewing.

I've a 1970's book here that I'm trying find (not the Dave Line book) that says something like:

An overnight mash, if anything, is better.

Of course, that was in the days when the preferred method of adding yeast was to float it on a piece of toast in the wort.

Cheers!
 
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