Can I do it all night? (mash)

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tre9er

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Ok, catchy-title to get people inside...

Overnight mashing. I've searched and I see varying opinions on the dryness of the finished product. Some say that the time the beer spends in the 140's will result in a drier beer...but others say that if it keeps it's original mash temp for an hour or two, all of the enzymes are denatured and thus there can be no more low-temp conversion anyway.

Is there any hard evidence anywhere? I'm planning on mashing at 153-154 and expecting to only lose 5-10 degrees overnight, probably a degree an hour...so in 2 hours I'll be at 152.
 
Not as catchy as you anticipated, was it ;)

Hard evidence at Kai Troester's very excellent site. Spend a work day and look around there. Loads of buried treasure.

http://braukaiser.com/download/Effects_of_mash_parameters_on_attenuation_and_efficiency.pdf

Nope. I rarely even start new posts anymore. I thought this might be a good one though because all of the threads I found were either from pre-2010 and/or went largely unanswered.

I thought it was interesting that the BYO article (IIRC) mentioned the added dryness of the final beer...but then it doesn't make sense to me that there would really be enough enzymatic activity after several hours to keep converting sugars.

Thanks for the link. I'll read-up.
 
Not as catchy as you anticipated, was it ;)

Hard evidence at Kai Troester's very excellent site. Spend a work day and look around there. Loads of buried treasure.

http://braukaiser.com/download/Effects_of_mash_parameters_on_attenuation_and_efficiency.pdf

What I conclude is that this data is somewhat helpful, but not entirely representative of a large overnight mash in a well-insulated vessel. Our temp drops will be nowhere near as large as Kai's experiments. I expect attenuation to NOT be greatly affected if a relatively high mash temp (say, 156) is used and the temp drop is roughly 1*/hr. The alpha amalayse will have much more time to be active while the betas will be denatured to a greater extent than in Kai's exeriments.
 
I mash overnight most of the time mainly because it works out best with my schedule. I use a 10gal igloo cooler and never noticed a difference in the dryness of my recipes.
 
I mash overnight most of the time mainly because it works out best with my schedule. I use a 10gal igloo cooler and never noticed a difference in the dryness of my recipes.

do you increase mash temp at all or stick with original recipe mash temp?
 
I do it in the oven. I start low and ramp it up over an hour or two and hold it until I’m ready for it. Overnight is fine.

I’ve never used an Igloo, but I don’t see why it wouldn’t work.
 
My report:

Began mash after 11PM, temps at 153. Next morning at 7:00 (after sparge water was nearly at temp) temp was 143. Happy with the minimal loss to ward off nasties.

Efficiency saw a big rise, up to 83% from low 70's with my usual 60m mash.

Next day I was done in 3 hours including all equipment cleaned and put away. I love this method. Will see if FG dries way out or not. I tend to think it won't because temps stay within a degree in the first hour in my MLT. Betting most enzymes were done by 90m.
 
I use a 70qt Coleman Extreme cooler for MLT, by the by. Its a "6-day cooler". I had a high water/grist ratio...nearly 2.0
 
I was listening to an episode of Basic Brewing Radio not too long ago and the guest, Randy Mosher, said that he mashes overnight all the time. He indicated that the enzymes are only going to work so long, and then there is nothing more to do. He saw no disadvantages to doing the mash overnight.

Also, I am confused as to why the beer might be drier. As I understand it, the drier beers come from a lower mash temperature and beers with more body are mashed at a higher temperature. However, the enzymes are denatured at higher temperatures, not lower temperatures. It is for this reason that when doing a step mash, you must always start with the lower rest temperature and move up through the steps. If the process were reversed, you would denature the enzymes at the higher temperature and cause nothing to happen at the lower temperature. So my confusion is why would a mash that is cooling from a higher temperature cause the enzymes to make a drier beer when (at least theoretically) they have already been denatured at the higher temps?

I think that you would be fine with mashing all night. Then you would have the added advantage of being able to start with the boil early the next morning. Mark:mug:
 
I don’t know for sure if increasing the mash temperature over time does anything different than holding the temperature. I’ve done it both ways and it seems that increasing the temp adds some extra malt complexity.

I’ve tried doing it on the stovetop, adding just enough heat to hold the temp, but it’s real tricky. It’s better and way easier to put it in the oven. At 250ºF it takes about an hour to mash out. If I match the mash temp I can hold it as long as I want.
 
Also, I am confused as to why the beer might be drier. As I understand it, the drier beers come from a lower mash temperature and beers with more body are mashed at a higher temperature. However, the enzymes are denatured at higher temperatures, not lower temperatures. It is for this reason that when doing a step mash, you must always start with the lower rest temperature and move up through the steps. If the process were reversed, you would denature the enzymes at the higher temperature and cause nothing to happen at the lower temperature. So my confusion is why would a mash that is cooling from a higher temperature cause the enzymes to make a drier beer when (at least theoretically) they have already been denatured at the higher temps?

The only reason I mentioned it is that some more "prominent" sources have mentioned a potentially drier beer as a result, however perhaps they were figuring the temps would drop rather quickly, as they did in Kai's experiment where he showed much higher fermentability with longer mashes. Holding the temps for as long as I do in my cooler before significant loss begins, I think there is denaturation and thus no further conversion of maltose.
 
Well, took a gravity reading this AM on the aforementioned pale ale, which was overnight mashed at a starting temp of 153...falling to 143 after 8 hours...

Beer temp was 57 and gravity read..... 1.002?!?!

It didn't taste hot or alcoholic. Tasted awesome actually...but this dry attenuation is puzzling
 
It could very well end up drier. The higher fermentability comes at low mash temps (140's). With an extended time in this range the wort could be very fermentable (drier). Enzymes are not denatured in the temp range you are working with so they will continue to work as long as there are starches, maltose, and maltotriose to "chop" up. Also, enzymes do not get "used up", they are just catalysts to the reactions taking place so without big changes in pH or temperature they will continue to work as long as there are starches and short chain sugars available.
 
helibrewer said:
It could very well end up drier. The higher fermentability comes at low mash temps (140's). With an extended time in this range the wort could be very fermentable (drier). Enzymes are not denatured in the temp range you are working with so they will continue to work as long as there are starches, maltose, and maltotriose to "chop" up. Also, enzymes do not get "used up", they are just catalysts to the reactions taking place so without big changes in pH or temperature they will continue to work as long as there are starches and short chain sugars available.

Interesting. Wonder how high id have to start the mash in order to get complete conversion before reaching lower, more attenuating temps?

While I know the enzymes don't get used up, why shouldn't all conversion be done within the first few hours? Why would there be starches left to convert?
 
I'm a lazy brewer so I've done overnight mashes and overnight cooldowns with no major issues although you will want to mashout before going to bed to keep conversion from continuing throughout the night and creating the 'extra dry' beer that the posters above have been experiencing.

Amylase enzyme is the main conversion enzyme that is working to create more fermentable sugars. At 158°F, amylase denatures in about 60 minutes. When it gets below 150°F, it will hang around for a long time. If you do not maintain enough heat to keep the mash in the 150°F-158°F range and denature all of the amylase, it'll keep working and dry your beer out.

So when doing overnight mashes, either make sure you can maintain that heat range (I shoot for 2.5 - 3 hours in that range but that might be overkill) or do a mashout before going to bed.
 
I like the idea but have yet to try it.

I am going to do a few like this since I do the preperation for brewing a little bit each night before I brew on the weekend, but I think this will make "brewday" a whole lot easier.

I have been brewing Milds and Ambers that Mash at about 154 and (maybe I just add a degree or two) let it go overnight,,, maybe add some "dextrine" malt to play it safe.

DPB







Do the
 
I'm a lazy brewer so I've done overnight mashes and overnight cooldowns with no major issues although you will want to mashout before going to bed to keep conversion from continuing throughout the night and creating the 'extra dry' beer that the posters above have been experiencing.

Amylase enzyme is the main conversion enzyme that is working to create more fermentable sugars. At 158°F, amylase denatures in about 60 minutes. When it gets below 150°F, it will hang around for a long time. If you do not maintain enough heat to keep the mash in the 150°F-158°F range and denature all of the amylase, it'll keep working and dry your beer out.

So when doing overnight mashes, either make sure you can maintain that heat range (I shoot for 2.5 - 3 hours in that range but that might be overkill) or do a mashout before going to bed.

Like I said, I typically don't lose even a degree in the first hour, so my 153 mash should have been 152.5 or so after an hour, then probably 151 after two hours. I figured by then I might have had full conversion anyway and therefore no more starches left to convert. This doesn't seem to be the case though.

This weekend I mashed at 156 for an OktoberFAST and again had efficiency in the low 80s. We'll see how far it attenuates in a week or two.

I'd still like more science behind why this is possible. If everyone does iodine tests to see if conversion is "done" after 45-60 minutes...how am I getting further conversion hours and hours later? Again, my temps are staying very near the initial mash temp for the first few hours (120m).
 
I'd still like more science behind why this is possible. If everyone does iodine tests to see if conversion is "done" after 45-60 minutes...how am I getting further conversion hours and hours later? Again, my temps are staying very near the initial mash temp for the first few hours (120m).

An iodine test is an imperfect science -- it shows high starch levels. Just because an iodine test passes, it doesn't mean the wort is starch-free, it just means the starch level is low enough to indicate enough conversion has taken place to proceed with brewing. This is one of the reasons I switched to a refractometer instead of the iodine test.

And the relationship between time, temperature, and enzyme denaturing is not linear. So if 158°F denatures in 60 minutes, 152°F can take exponentially longer which would keep amylase active well past the 120 minute mark.

So your problem is you are letting amylase over-convert the wort resulting in a beer that is too dry. You basically have two options:

  1. Mash at a higher temperature and the amylase will denature faster, resulting in a less fermentable wort.
  2. Perform a mashout (this is what I do) at some point in the middle of the night. Bring it to 170°F for 10 minutes and the amylase will denature.
 
I'm considering adding some carapils...wonder how much...? That or increasing the mash temps. I'll have to mess around with it a little. I love the convenience of getting up and only having a few hours left to finish a brew, though.
 
There is alpha and beta amylase. One does coarse 'cutting' of starches (chainsaw on a tree) and the other one, whichever works at low temps, does the fine cutting that results in the simple sugars yeast eat (like clipping the smaller branches off with shears).

So it isn't just whether you have full conversion or not, it is whether you have left longer, bigger sugars (mouthfeel and sweet) or have cut everything up into simple sugars (very fermentable wort).

I think.
 
I'm considering adding some carapils...wonder how much...? That or increasing the mash temps. I'll have to mess around with it a little. I love the convenience of getting up and only having a few hours left to finish a brew, though.

I'm not a fan of doctoring recipes to compensate for a brewing methodology but you could add carapils or even malto-dextrin to liven up the body. But then you'd be adding more sugars which means more booze and you'll have to adjust the recipe again to keep the BU:GU in the same ratio.

If I were you, I'd crank your mash temp up to 158°F as the starting temp and see how much conversion you get. I imagine (aka total guess) that the enzymes should have about 2 hours of activity which should keep your FG a little higher. If it's still too dry, try 160°F next time. If it's too sweet, drop it 2°F and try again.

You should have it dialed in after 2-3 batches. Just keep notes so you can have you process down on paper.

Now once you can do that, you can go epic lazy:

Sunday Night: Overnight Mash
Monday Night: Boil and Overnight Cooling (AKA no-chill)
Tuesday Morning: Rack to a carboy and pitch

While it does take 3-days to complete a brew, you don't have to do much 'hands on' work other than be around for the hop additions. You just have to be comfortable with your equipment so you aren't having to worry about temps every 15 minutes.
 
Now once you can do that, you can go epic lazy:

Sunday Night: Overnight Mash
Monday Night: Boil and Overnight Cooling (AKA no-chill)
Tuesday Morning: Rack to a carboy and pitch

While it does take 3-days to complete a brew, you don't have to do much 'hands on' work other than be around for the hop additions. You just have to be comfortable with your equipment so you aren't having to worry about temps every 15 minutes.

Already doing something like this! Overnight mash, morning sprage/boil/initial chill, throw in ferm-chamber with temp probe taped to side of fermenter and 6-24 hours later, I pitch.
 
There is alpha and beta amylase. One does coarse 'cutting' of starches (chainsaw on a tree) and the other one, whichever works at low temps, does the fine cutting that results in the simple sugars yeast eat (like clipping the smaller branches off with shears).

So it isn't just whether you have full conversion or not, it is whether you have left longer, bigger sugars (mouthfeel and sweet) or have cut everything up into simple sugars (very fermentable wort).

I think.

Yeah, I understood how that worked before I started. What I didn't know was how long it takes to denature beta amylase at certain temps. The goal is to denature most of it within the first few hours, before the temp drops into it's sweet spot. That or I wasn't sure how much, if any, starches were really left after a few hours of conversion.

I'm learning more about how those enzymes work in relation to time and temp. It seems they are pretty resilient.
 
So to review:

First overnight mash I began the mash at 11PM at a temp of 153. Temp eight hours later was 143. Figure it was 151-153 for the first two hours. 83% efficiency, Attenuation was 97% if my math is right (1.048 to 1.001).

Second overnight mash began at 156, 7 hours later it was 147. 80% efficiency, 1.049 OG. Will report back attenuation when I know it.
 
I believe I'll be trying this myself sometime soon. I have a 10 gal igloo I'll use and blanket the heck out of it....BUT, I have a question for those that use Ovens to do this. HOW?!

Isn't the oven dial limited to 200*F as far as the "low" point goes? How do you keep it at 160?....or whatever temp you're going after?
 
I believe I'll be trying this myself sometime soon. I have a 10 gal igloo I'll use and blanket the heck out of it....BUT, I have a question for those that use Ovens to do this. HOW?!

Isn't the oven dial limited to 200*F as far as the "low" point goes? How do you keep it at 160?....or whatever temp you're going after?

My guess is their ovens set from 150 up. Some do. Also I bet they're using kettles for mash tuns. Most coolers wouldn't fit very well in an oven.

My recommendation is to take the mash temp of the recipe and up it by 2 degrees. That's what I'm going to be doing. If it's a lower mash temp, maybe ramp it up 3-4 degrees. You want to avoid sitting in the high 140's without having denatured beta amylase. Otherwise you'll end up with super dry beer like my 1.001 Pale Ale.

I'd say the lowest I'd mash overnight, without much crystal or dextrine malt, is 155. That will still likely result in a dry-ish beer.

We'll see where my 156 mash (oktoberFAST) comes out. I'm guessing it will be slightly more dry than I wanted, but with 10% crystal and 40% Munich I'm hoping there's still some malt character.
 
I use two 12 qt stainless pots. My oven has an analog thermostat, marked from 150-500F. If I put the mash in a 175ºF oven it will mash out over night. If I set it to 200ºF the mash will go to 170º F in an hour or two. Then I reduce it to 175ºF to maintain the mash temp until I’m ready to lauter.

If your oven won’t go below 200ºF you could experiment with turning it on and off. I wouldn’t leave it at 200ºF overnight. If you turn it off when you go to bed, it’ll still be pretty hot in the morning.
 
I use two 12 qt stainless pots. My oven has an analog thermostat, marked from 150-500F. If I put the mash in a 175ºF oven it will mash out over night. If I set it to 200ºF the mash will go to 170º F in an hour or two. Then I reduce it to 175ºF to maintain the mash temp until I’m ready to lauter.

If your oven won’t go below 200ºF you could experiment with turning it on and off. I wouldn’t leave it at 200ºF overnight. If you turn it off when you go to bed, it’ll still be pretty hot in the morning.

I suppose there's a way to hook up a temp controller to a 220v oven with analog dials so you can precisely control it's temp if it won't go below 200...but that seems like overkill.
 
My guess is their ovens set from 150 up. Some do. Also I bet they're using kettles for mash tuns. Most coolers wouldn't fit very well in an oven.

My recommendation is to take the mash temp of the recipe and up it by 2 degrees. That's what I'm going to be doing. If it's a lower mash temp, maybe ramp it up 3-4 degrees. You want to avoid sitting in the high 140's without having denatured beta amylase. Otherwise you'll end up with super dry beer like my 1.001 Pale Ale.

I'd say the lowest I'd mash overnight, without much crystal or dextrine malt, is 155. That will still likely result in a dry-ish beer.

We'll see where my 156 mash (oktoberFAST) comes out. I'm guessing it will be slightly more dry than I wanted, but with 10% crystal and 40% Munich I'm hoping there's still some malt character.

I'm using a 10 gallon cooler for my tun, and am thinking about trying this on my next brew. My question has to do with mashout. Are you doing any sparging after the overnight mash? In my head, I'd imagine you'd lauter in the morning, and then heat the sparge water to 170, hold for 10-ish minutes, and then drain to the kettle for the boil like normal. Is there any reason you wouldnt be able to sparge as normal? I dont imagine there would be. Are you also doing a 60 minute boil, or do you boil for longer?
 
I'm using a 10 gallon cooler for my tun, and am thinking about trying this on my next brew. My question has to do with mashout. Are you doing any sparging after the overnight mash? In my head, I'd imagine you'd lauter in the morning, and then heat the sparge water to 170, hold for 10-ish minutes, and then drain to the kettle for the boil like normal. Is there any reason you wouldnt be able to sparge as normal? I dont imagine there would be. Are you also doing a 60 minute boil, or do you boil for longer?

There's really no point in mashing out in the AM. If you're set on doing that, do it before bed, then leave the tun overnight. The conversion is really as "done" as it's gonna be by the AM, so mashing out won't "stop" anything.

Mashing out the night before it the only way to have attenuation similar to a "normal" mash. Otherwise, as I've experienced, not enough beta amylase is denatured so it continues to work thru temps into the 140's, resulting in a very fermentable wort.

The way I plan to avoid this is to up the mash temps accordingly. Beta begins to be denatured from 154-162. It doesn't happen immediately, which is why you can mash at 154 and still get good fermentability/attenuation.

I think 155 is a good bet for a relatively dry beer (but not super dry). That allows beta to work for a while but most of it is denatured before temps drop down into it's sweet spot.

For a larger bodied beer, I'd just increase by a few degrees. I'm sure there's a formula that could be derived from this if you know your average temp loss over time and the sugar profile you're looking for.

To answer your question though, I wake up, flip-on the sparge water, make coffee, stir mash (no mashout), then start running off. Then I sparge as usual.

It's literally like I just mashed for an hour and continue like normal, but someone froze time on me and it was actually 8 hours.
 
I'm using a 10 gallon cooler for my tun, and am thinking about trying this on my next brew. My question has to do with mashout. Are you doing any sparging after the overnight mash? In my head, I'd imagine you'd lauter in the morning, and then heat the sparge water to 170, hold for 10-ish minutes, and then drain to the kettle for the boil like normal. Is there any reason you wouldnt be able to sparge as normal? I dont imagine there would be. Are you also doing a 60 minute boil, or do you boil for longer?

Don't forget one of the reasons we want to raise the temp to 170 is to get the sugar into solution.

So from all my reading about BATCH SPARGING it would lead me to believe that you should get it up to 170 and leave it there long enought for the sugar to release from the grain just like you would on the second sparge...

There are all sorts of descriptions on how to do this out there.

Happy Brewing!
 
There's really no point in mashing out in the AM. If you're set on doing that, do it before bed, then leave the tun overnight. The conversion is really as "done" as it's gonna be by the AM, so mashing out won't "stop" anything.

Mashing out the night before it the only way to have attenuation similar to a "normal" mash. Otherwise, as I've experienced, not enough beta amylase is denatured so it continues to work thru temps into the 140's, resulting in a very fermentable wort.

The way I plan to avoid this is to up the mash temps accordingly. Beta begins to be denatured from 154-162. It doesn't happen immediately, which is why you can mash at 154 and still get good fermentability/attenuation.

I think 155 is a good bet for a relatively dry beer (but not super dry). That allows beta to work for a while but most of it is denatured before temps drop down into it's sweet spot.

For a larger bodied beer, I'd just increase by a few degrees. I'm sure there's a formula that could be derived from this if you know your average temp loss over time and the sugar profile you're looking for.

To answer your question though, I wake up, flip-on the sparge water, make coffee, stir mash (no mashout), then start running off. Then I sparge as usual.

It's literally like I just mashed for an hour and continue like normal, but someone froze time on me and it was actually 8 hours.


I agree 155 should be a save temp but it depends on your mash tun and how long it will retain heat...

I am seeing a lot about Beta Amylase going back to work when the temperature falls into the 140(s)

According to Palmer: "Alpha works best at 154-162°F, while beta is denatured (the molecule falls apart) at that temperature, working best between 131-150°F."

AND: according to other sources the highest a Beta Amylase works is 152.6 and;;; I assume denatures above that.

SO: if we Mashed In at 154-156 and stayed there for an hour it would seem to me that we would get full conversion and denature "beta" so there would be nothing left for it to convert and dry it out. (The temp described in the quote)

I know that these temps are from a labratory and when actually brewing it might not work that way but I did not think that beta would further breakdown the sugars created by alpha;;; so you should still get a good mouth feel...

Then again this gent has done it and I am just "pontificating".... but I am inspired and will try it my self...
 
That may very well be. If my oktoberFAST comes out with decent body I will be apt to believe we can denature BA at/above 154 and end up with an average bodied beer.

My 153 was incredibly dry despite holding darn near that temp for an hour and then slowly dropping. The 154/155 seems like the sweet spot for medium-to-slightly-dry beers with this method.
 
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