Overnight Mashing

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illin8

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OK...so I tried something different last night/today brewing Biermuncher's Centennial Blonde. I mashed in last night at around midnight and then went to bed. I woke up at 6:10 and started heating the sparge water, made coffee, got some stuff together and then mashed out and proceeded as normal. It worked out pretty well, after clean-up and having every thing done I was done around 10:30 am...I'd be quicker if I didn't have a tiny basement w/ stuff everywhere (no shed or garage and only 1/2 basement - I need more room!).

Anyone see anything wrong with doing it this way or anything to be concerned about?
 
I bet your beer is going to very dry. You may get a little sour going on. When iv left my cooler full of spent grains over night, it got a little funky smelling. Bacteria love sweet wort.

In your case, ones you boil the wort, your golden. You may discover a new recipe.
 
If the temperature gets too low (below 120F), the mash might sour and boiling will not get rid of sour.
 
By the time I drained first runnings, temps were in the mid 130s...hopefully souring wont be a problem.
 
I've never left my mash over night but I have left my spent grains for a day or two because I was lazy. Spent grains sour really quickly and end up smelling like dead horse balls. :eek:
 
I've done it a bunch of times.
Some recipe tweaking (CaraPils is your friend) and I have been very happy with the results.
I wrap my cooler up in a sleeping bag and my temps are always in the 140's in the morning.

Works really well with my house bitter
 
I've never left my mash over night but I have left my spent grains for a day or two because I was lazy. Spent grains sour really quickly and end up smelling like dead horse balls. :eek:

Indeed... Nasty. I had to rinse my cooler very well to get that smell out.
 
I don't get it...if the cooler is sealed up and holding temps well, the majority of the conversion will occur within the first hour or two at desired mash temp. The sustained temps will pastuerize any 'bad' things in the cooler during that time. How could it sour? I mashed in around midnight, got up at 6 am, fired up the sparge water and waited. When the batch water was close to temp I started vorlaufing and running off at around 7, so that would be 7 hours and the temp of the mash was around 135*. I double batch sparged with 190* water to compensate for the lower mash temp during runoff...maybe increase tannin extraction but for such a short contact time with the mash and the lower temps during runoff I figured it should be minimal.

After reading other posts on this and other boards I thought it would be ok as long as the temps didn't get below 120*...even if the temp dropped below 150* after 2 hours the majority, if not all, of the conversion should have taken place. It didn't smell sour or bad during runoff. Ah well...time will tell I guess.
 
I'm no expert at prolonged mashing, but I suspect the above comments are right - if you're wort was insulated and didn't drop below 140 or so, you should be OK. My question is, what advantage is there to mashing overnight for so long? From my relatively green perspective, the potential cons would prevent me from trying it. Is there a reason?
 
yeah I left spent grains in the cooler for three days
and it smelled like an old lady fart passing through an onion
 
In The Home Brewer's Answer Book by Ashton Lewis, someone asks this very question (on pp. 391-2 in my edition). Lewis is the Q&A guy for Brew Your Own magazine. His answer basically says that if it makes things easier for you, then definitely do it. His only caveats are a very dry beer if the temps reach the 140-145 range, or a sour beer if the temps go below 120.

He recommends putting the mash tun overnight in your oven set at its lowest setting - as long as you check first to see if that's not too high.

The final line of his answer reads "As long as the mash temperature is adjusted to address concerns about overly fermentable wort and bacterial spoilage, your method is a real daylight time-saver!"
 
I don't get it...if the cooler is sealed up and holding temps well, the majority of the conversion will occur within the first hour or two at desired mash temp. The sustained temps will pastuerize any 'bad' things in the cooler during that time. How could it sour? I mashed in around midnight, got up at 6 am, fired up the sparge water and waited. When the batch water was close to temp I started vorlaufing and running off at around 7, so that would be 7 hours and the temp of the mash was around 135*. I double batch sparged with 190* water to compensate for the lower mash temp during runoff...maybe increase tannin extraction but for such a short contact time with the mash and the lower temps during runoff I figured it should be minimal.

After reading other posts on this and other boards I thought it would be ok as long as the temps didn't get below 120*...even if the temp dropped below 150* after 2 hours the majority, if not all, of the conversion should have taken place. It didn't smell sour or bad during runoff. Ah well...time will tell I guess.


It'll be fine, as mentioned it may be pretty dry, but if so you could probably add a bit of malto-dextrin before bottling to up the body a bit. I know there are several people who always mash overnight and have made it work out really nice. Your temp stayed high enough that you won't get any souring.
 
The reason I did it are two-fold (1) 23 month son (energizer bunny who has a hard time leaving my side) and (2) an SWMBO that doesn't give me much time to myself, let alone 5 solid hours.

I don't think it saved that much time really...I wasn't able to heat the sparge water DURING the mash so I lost the hour that I otherwise would have gained (so to speak). I'll probably just find a way of not checking the HLT or MLT every 5 minutes and watch the kid, and also coordinate the boil-chilling-pitching-cleaning part of the brewday with his nap.

If it is dry, how much malto-dextrin should I add?
 
I've done my mash and sparging the night before and my boil the next day before. That worked out well although a little thin. Probaly from not Mashing out before the wort sat over night. That's correct reasoning right?
 
If it is dry, how much malto-dextrin should I add?

Hard to say, you could try to add it to taste by taking a glass of it and putting a small measured amount of malto-dextrin in then tasting, if it helps then you can scale that up and boil along with the priming sugar.
 
Just a follow-up. I did this overnight mash with Biermuncher's Centennial Blonde recipe. Original gravity was 1.045, I just pulled a sample after 10 days in the primary and it has finished up 1.008. BM noted an OG of 1.039 and FG of 1.008. The sample tasted great, no sourness or anything discouraging that I could tell. So far so good...I'm gonna let it sit a few more days before I bottle...I don't think this one will need any more than 2-2 1/2 weeks in the primary.

1.045 to 1.008 has BeerSmith putting my apparent attenuation at 81.6% and real attenuation at 66.3%...which number means what and which is more important?
 
I've never left my mash over night but I have left my spent grains for a day or two because I was lazy. Spent grains sour really quickly and end up smelling like dead horse balls. :eek:

Yeah, and usually by the next day. Hard to beleive it came out ok, but I don't think I would even try after smelling that stuff the next day. One time during summer the smell the next day almost made me throw up.
 
I have mashed out then left it over night. Sparged and boiled the next day as there was a family emergency and I had no choice. Worked out fine. I think I would mash out though.

I've also done a mash out and sparge then boiled the next day as well. The few times I have done this (usually due to a brew day taking too long) I have not had any souring, but you do run the risk.
 
I just can't see how the grist can turn to rotting dead horse balls in 7 hours and still above 130* and with 1.5 qts/gallon in the cooler...I guess I will trust you all and not do it again though (<scratchin my head>)
 
I just can't see how the grist can turn to rotting dead horse balls in 7 hours and still above 130* and with 1.5 qts/gallon in the cooler...I guess I will trust you all and not do it again though (<scratchin my head>)

Well to be fair, once the wort is completely drained there is nothing to keep the heat so it just sits there warm and stewing so I don't know how it would smell at 130* overnight but man that spent grain turns my stomach the next day when I go to clean out the cooler. I am going to say this is about 16 hours after draining.
 
I think there is a misunderstanding...I mashed IN at midnight adding 3.5 gallons of water to get me to 152 after stirring and left it alone until the morning. First thing in the morning I began heating sparge water and came back when it was close to temp and started my first runnings. So instead of a 60 second mash I had more like a 420 minute mash (12am to 7am). Once the sparge water was up to temp I drained my first runnings and did a double batch sparge. At no point did the grain bed go dry for any length of time AFTER I mashed in.

I definitely can see where dead horse balls would be a good description if it just sat wet and dry in the cooler for a while.
 
If you did this with a HERMS, you could keep the temp up at sacc. rest all night.

But, I dunno why youd do it then, the HERMS lets you walk away during the mash and mashout anyway.
 
I'm in the habit now of mashing and sparging, then heating to around 200F, then insulating the pot, all on Friday night. By Saturday morning it drops to around 180F. I boil, and I'm done by 8:30AM so I can spend time with the family. Works great. No flavor problems.
 
I'm in the habit now of mashing and sparging, then heating to around 200F, then insulating the pot, all on Friday night. By Saturday morning it drops to around 180F. I boil, and I'm done by 8:30AM so I can spend time with the family. Works great. No flavor problems.

This would also denature the enzymes so you are not getting more conversion overnight. Since you don't drop below 180 you also don't have anything that can start to sour it get in the pot (Additionally you boil it for 60-90 min anyway). Seems like a good solution.

I'm wondering if this would be a great way to do an IPA, throw in your first wort hops for 8-10 hours :D
 
Even though this thread is over a year old, i wanted to add some infromation for future inquires. Last night 8/13/10, I decided to make a pale ale, so I mashed in with 10 lbs of grain and 12.5 qts of water. I hit 153 deg and put the lid on at 10:00 pm. I am using an Xtreme 5gal cooler made by Coleman.

The next morning at 8:00 am the temp was 145 deg. That's only an 8 deg drop over 10 hours. I am now heating up my sparge water to 200 deg and I am going to mash out and then sparge for about 30-45 min. After this whole process is over I hope to end up with a really good pale ale.

The objective here was to split up the brew day so it would not take 6 hours out of my Saturday and would keep good relations with SWMBO! I am hoping that after the 2 hours it took last night to set up and mash in, today will only take 3-4 hours to complete.
 
OK, finished cleaning up at about 1:00 pm and put the brew equipment away. It took me 5 hours today! That did not save me much time. I did spend a little extra time cleaning and transferring some other beers to the keg but wow! I had no idea it would take that long.
The next time I brew I am just going to set everything up the night before and get my water in the HLT and get up earlier, maybe around 6 am and fire the kettle.
 
reviving this thread again as I just did my first over night mash, just wanted to put my experience so far out there...

7.5 Lb 2-Row
.5 lb Black Patent
.5 lb American Chocolate
.5 lb British Chocolate
1 lb Flaked Oats

Stabilized @ 156 degrees with 13 quarts of water. It was just below 150 when I woke up the next day. Didn't have time to brew before church, so I added some near boiling water to kick it up a bit.

Opened up the valve to start recirculating, and it was completely stuck. Barely a drip coming out. Little worried at this point...time to relax and have a home brew. I moved the mash into my brew pot, cleaned out the Mash Tun, and put it back in, and it was flowing fine. Proceeded with the rest of my brew day. Pitched in my London Ale yeast and it was fermenting like crazy about 18 hours later @ 68 degrees. Almost 48 hours later and the air lock is bubbling like crazy still.

This is essentially the same recipe I brewed a few months ago, but didn't do Over Night mash that time. My efficiency is up from 72.3% - 76.6.
 
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