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Mash, runoff, then let wort sit overnight? UPDATED!

My supplies are getting low and I’d like to squeeze in a brew day next weekend. I want to break up the usual 5-6 hour brew day into two different days. So, here’s what I’m planning:

  1. On Friday night, nash and batch sparge per usual, collecting the full pre-boil amount.
  2. Bring wort to a boil, kill the flame, then cover and let it sit overnight. I might even insulate the kettle.
  3. Sleep 7-8 hours assuming my young kids allow it.
  4. Wake up Saturday morning, start boil and finish up within 2-3 hours.

See any problems with this? I read that bringing the wort to a boil for a minute or two will kill any chance of bacterial infection. I don’t foresee any changes to the wort or finished beer just because it’s sitting overnight. I also don’t want to do an overnight mash because I’m not sure how well my mash tun will retain heat over a long period of time.

Any advice is appreciated.

You could save a little time by not bringing it all the way up to a boil. 170-180°F should be enough to pasteurize and to “lock in” the fermentability of the wort.

[quote=“a10t2”]You could save a little time by not bringing it all the way up to a boil. 170-180°F should be enough to pasteurize and to “lock in” the fermentability of the wort.[/quote]+1

+10

I mash and runoff one day and boil the next all the time and have never had a problem. There’s no need to bring the runoff to a boil and if you do a mash out at 168-170 as part of the mash, there’s no reason to reheat the runoff to that temp as the mash and runoff will be pasteurized if you maintain that temp for 10 min (as you would do in a normal mash out). Just be sure that whatever you leave the runoff in is clean and you’ll be fine.

Sounds good. I’ll go ahead with the plan.

And, thanks for the input. I’ve posted many times and gotten quick, helpful responses from both of you guys. I really appreciate the fact that you’re willing to help a fellow brewer, and the advice you’ve given has been invaluable.

Jason

Aw, shucks… :oops:

There’s been a couple of threads on this and each time I feel compelled to tell about when I did this, and the next day had krausen.

The unboiled wort had turned and had to be dumped. It was the middle of August and humid so there’s that. I have done it many times with success. Just be careful. Maybe the pasteurizing approach will do it.

:cheers:

[quote=“Chinaski1217”][quote=“Shadetree”][quote=“a10t2”]
And, thanks for the input. I’ve posted many times and gotten quick, helpful responses from both of you guys. I really appreciate the fact that you’re willing to help a fellow brewer, and the advice you’ve given has been invaluable.

Jason[/quote][/quote][/quote]

Concur. Everything I know about brewing has been from this forum, and good folks like shade tree and a10t2.

Hugs.

:cheers:

[quote=“edawgwv”]There’s been a couple of threads on this and each time I feel compelled to tell about when I did this, and the next day had krausen.

The unboiled wort had turned and had to be dumped. It was the middle of August and humid so there’s that. I have done it many times with success. Just be careful. Maybe the pasteurizing approach will do it.

:cheers: [/quote]

So, did you not bring it to a boil, or at least heat it to 170-ish?

[quote=“Chinaski1217”][quote=“edawgwv”]There’s been a couple of threads on this and each time I feel compelled to tell about when I did this, and the next day had krausen.

The unboiled wort had turned and had to be dumped. It was the middle of August and humid so there’s that. I have done it many times with success. Just be careful. Maybe the pasteurizing approach will do it.

:cheers: [/quote]

So, did you not bring it to a boil, or at least heat it to 170-ish?[/quote]

No. I sparged then let it sit overnight. It was close to 170 during runoff. If you bring it to a boil, won’t you still run the risk of infection as it sits overnight cooling? I guess heating it up before going to bed will kill any germs that came out of the mash. Whatever the answer, the process usually works for me anyway, I just had that one bad experience.

:cheers:

If you keep the pot lid on the chances of infection are low, and even if you saw something starting to work you could boil and kill it at a point where it mosst likely hadn’t affected flavor.

The only thing I don’t like about this, is wasting all that heat in the warm wort and having to start from room temp to bring it to a boil.

Oh and +2 to the kudos for Sean and Shade. You don’t get to 7000 posts without giving at least a couple pieces of good advice along the way.

+1 on the props to a10t2 and Shadetree. Many people have been immensely helpful in my young brewing career, but none so much as you two and Denny.

Re: the subject at hand, a few weeks ago I mashed in the afternoon, drained, sparged, covered, then let it sit for ~4 hours while I helped around the house and got my son fed and in bed. Once he was asleep I started the boil and everything went well. If you can do that, the chances of picking up an infection might be a hair lower and you won’t lose quite as much heat.

This topic comes up from time to time. Sometimes family life gets in the way of an uninterrupted brew day. Basically, I mash and drain as usual. Then I do a hot tap water batch sparge and go to bed while it is draining. I start off the next day with the boil.

I’ve done this numerous times without issue. I cannot tell the difference between beers made this way and beers made in one session.

So, for those who have experienced problems with this before, how did you know the wort had been infected? What did you see or smell?

I went ahead and mashed, collected, then heated the wort to 200 degrees last night. I then kept it covered with a lid (which hadn’t been sanitized, but had been cleaned and put on the kettle while it was heating) and wrapped blankets overnight. The temp was about 138-140 this morning, about8 hours later, and there were some little whitish floaty things on top of the wort. There weren’t a ton of them, the surface wasn’t covered or anything, but I didn’t know what it was. I thought maybe it might be just particulates from the mash.

There was an odd smell when I first took the lid off too, but it seemed to dissipate quickly. I thought maybe having all the fumes trapped overnight would maybe cause this odd smell, though I don’t know why. I’ve never done this before.

I’m going ahead with the boil as planned, but I’ve lowered my expectations. I’m not sure how to tell if it’s been infected.

Majority of the time as long as you dont fall well under 140 for an appreciable amount of time you will be fine.

I’ve done this too; the mash+sparge takes a while, and it’s definitely nice to take a few hours to sit with dinner, a beer, some tv. whatever. :slight_smile:

one technique that might be worth doing: get some clips, clamp or a bungee and seal the lid for your kettle, so that both nothing can get in, nor can it easily get knocked off. Then wrap the thing in a towel or a blanket, which would keep some of the residual heat in (if you’re doing the boil within 4-6 hours of the mash)

i’ve always just made sure to mash out high enough and i’ve not yet had any ill effects from it.

I’d boil it and then keep it covered overnight. The biggest risk of infection comes from the bacteria on the grains themselves. But, you also want to make sure you destroy any enzymes in the wort.

I just did a batch like this over the weekend. Mashed and sparged Saturday night. Boiled, cooled and pitched yeast on Sunday. I’ve done it many times with ZERO ill effects. I agree that wasting heat stinks but it’s either that or I don’t brew (due to time constraints). On the positive side, my banjo burner has little trouble bringing the cooled, room temp wort to a boil.

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