Mash and boil on separate days?

I know this has been discussed, but I haven't found a thread where it is completely clear what is being asked.

I know if I leave the wort on the grains over night the Lactic Acid will create off flavor, but if I mash for my standard amount of time, sparge, and boil to kill the bacteria; then I store it over night in sanitary conditions and boil/hop addition the following day, am I safe?

Thanks!

Seems plausible...I don't think you'd have to boil, maybe above pasteurization temp for 10-15 min (+160F)

helibrewer said:

maybe above pasteurization temp for 10-15 min (+160F)

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Nice, I didn't even think about pasteurization temp!

If you're going to sparge and boil, why not just finish the batch?

Or you can mash overnight. I've done it a couple of times. Wrap a sleeping bag around your mash tun to help hold the temps, but after a couple of hours the temp really doesn't matter all that much. Some people claim that such a long mash results in a thinner beer, but it's not that noticeable. I haven't had any issues with a lactic flavor when I've done this.

After mashing overnight, just get up, sparge and complete your batch like normal.

Here's one thread on overnight mashing : https://www.homebrewtalk.com/f36/overnight-mash-keeping-my-cool-295579/

Right on,

I can only steal a few hours on Saturday and a few on Sunday and I have a deadline on the batch. I know I don't have time to get 10 gallons up to boil, boil for 60, and then cool, pitch, and clean up in time so it would be great to cut it into two sessions. I'm interested in the mashing over night idea, i just worry about the bacteria in the grains, but if that is a non-issue fantastic!

Confused. You seem to be asking about overnight mashing but also mention lactic acid and souring. Are you talking about a sour mash? They are two completely different things.

Originally I wasn't talking about overnight mashing, just storing wort overnight and boiling the following day. I read, however, that the bacteria in the grains could have a souring effect on the beer if allowed to sit overnight thus making a sour wort and eventually sour beer. Just trying to see what my options are to break a brew day into two shorter brew days.

I do it regularly. As long as your mash temp doesn't get below 140. You will be fine. If lower than that it will slowly start to sour.

Love it, SWMBO won't castrate me for brewing all day on her Birthday...just half the day.

Maybe an electric heating pad (the kind used to relieve sore muscles) under or around the mash tun?

A lot of people have had success with an overnight mash. I would think starting the mash at a high temp (158ish) and keeping it as insulated as possible would counteract the thin beer Sparty mentioned. Maybe a little carapils or flaked whatever would be helpful as well. Mash hopping might help keep the lacto at bay.

kingwood-kid said:

Mash hopping might help keep the lacto at bay.

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I like how that sounds, would I just put my first hop additions in then? part of them? It's a 10 gallon batch so I am bittering with 2 oz of Cascades...Just put one in or get after it with both?

So I just poured my water into the cooler with the grains, but I'm pushing it with the temp, digi reads at about 164, some say for overnight mashing to go higher right away, ideas?

I've done a few brews with overnight mashes(I BIAB) and havent had any problems, flavour or otherwise. I target my mash temp as I normally would, no compensation for overnight mash, lag well, mash out in the morning having lost about 10degC over maybe 10 or 11 hours. Its a huge timesaver for me and I'll be continuing the practice. My next batch I intend no-chill like the Aussies seem to be doing(guys on biabrewer.info seem to do this with great success). Its a porter so itll be dark anyway. I intend cutting my brew day into 3. Day1-dough in. Day2-mash out and boil. Day3-Decant off trub and pitch. It also means I can save enough wort from the boil to make a starter ready to pitch with the original beer.

gcsowden said:

I like how that sounds, would I just put my first hop additions in then? part of them? It's a 10 gallon batch so I am bittering with 2 oz of Cascades...Just put one in or get after it with both?

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You could put in 2 ounces of Cascade, but don't figure on it replacing your bittering addition. I don't know how many IBU are contributed but it's not a lot. I've mash hopped on my Pliny clones and it doesn't add much bitterness.

Great Krausen in both carboys from the ten gallon batch. Waiting to see what it tastes like and what the FG is, but so far so good after the overnight mash. Started the mash at 155, 12 hours later it was at 148...nice.

Well done Gcs!!! Hope you're converted

It takes 12-18 hours to sour the wort.
Overnight mashes shouldn't be an issue, just boil in the morning.

The op mentioned finishing the mash and then letting it sit overnight before boiling and adding hops. This was something I was thinking about because I can't seem to find more then 3 hours at a time to brew. It sounds like most comments are saying to mash overnight and finish in the morning. Is one way going to produce better beer than the other or have less risk in not being good?

I wouldn't mash higher than normal. By the time the temp drops during the night, wouldn't conversion be complete anyway?

Grantman1 said:

I wouldn't mash higher than normal. By the time the temp drops during the night, wouldn't conversion be complete anyway?

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From everything I've read it appears that after an hour or so there's very little happening with the mash wrt conversion. I do all my beers this way now

If you do a mashout at 168, it theory, all of your mash has been pasteurized. That should be enough to denature beta amylase and kill any unwanted lactobacillus. Over night should be fine. Just do your mash the way you normally would, hit your mashout and don't touch it or open it until the next morning. Post results please!

seabass07 said:

If you do a mashout at 168, it theory, all of your mash has been pasteurized. That should be enough to denature beta amylase and kill any unwanted lactobacillus. Over night should be fine. Just do your mash the way you normally would, hit your mashout and don't touch it or open it until the next morning. Post results please!

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I've been doing it for my last few brews without a problem and I just lag and leave(I BIAB). I mash out the next morning and pull bag

I do it too. I work odd hours and after a 12 hour shift, would prefer to split the brewing into 2 evenings.

I have raised the wort to ~180*F, then let it sit covered for 20 hours or so before starting the boil. I have also just collected runnings into 5gal buckets and let it sit until the next evening without additional heating. If there is any souring that occurs in that amount of time, I haven't detected it. Since I brew indoors in a small apartment, I actually prefer doing the 180*F heating the day before, but that has more to do with the fact that I like having the wort on the stove, where all I need to do is twist a knob to start heating... as opposed to transferring and lifting the next day to start the brewing. Either way works. Most guys who are seriously trying to sour their worts will go for 3-9 days or so... By comparison, any souring I encounter ought to be minimal.

seabass07 said:

If you do a mashout at 168, it theory, all of your mash has been pasteurized. That should be enough to denature beta amylase and kill any unwanted lactobacillus. Over night should be fine. Just do your mash the way you normally would, hit your mashout and don't touch it or open it until the next morning. Post results please!

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I've always been curious about this--if 168F kills lacto, won't the boil take care of it as well? Why worry about souring in that case? I feel like I'm missing something!

Not sure if I understand the question. The souring talked about in this thread is mash souring from letting it sit overnight. You'd need a lot of bacteria for that to happen in such a short time. You need to pitch some fresh grain or cultures into your mash after it cools for it to sour and even then, overnight is probably not enough time. The boil will kill the bacteria, but won't remove any lactic acid already present from their previous activity.

seabass07 said:

The boil will kill the bacteria, but won't remove any lactic acid already present from their previous activity.

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That clears it up. Thanks, seabass07!