Mash the day before brewing?

I usually choose to brew on the weekend, just because I have a hard time carving out enough time after work during the week. Is it reasonable to mash and sparge one evening, and then come back and start the boil and finish brewing the next evening?

I know there's obviously a risk of contamination, but wouldn't that risk be minimal after completing the boil?

I'm a pretty new brewer, so I would appreciate the insight of somebody that's already learned some lessons.

Thanks!

That has become our standard method. "Brew Day" stress went way down and the cost went down too because we no longer buy ice for the cold crash. Make sure you use a "hop sock" or something that allows you to remove the hops at the end of the boil or your IBU will be more than the recipie called for.
I guess the main thing to focus on is getting the wort down to pitching temperature the next day. When the boil is done, we leave the brew pot lid off and use a temperature alarm device to notify us when the wort has cooled down to say 155* F before putting the lid on to keep further airborne "bugs" out. This helps the wort to cool faster. Then, just let it sit on the stove and don't remove the lid again until ready to transfer the wort into your carboy and pitch your yeast. If you live in a hot place this method might not work so well but where we live even in the summer, it gets cool enough in the evenings that I only have to point a fan at the brew pot for a couple of hours the next morning before it's down to ideal pitching temp.
Anyway, this goes against home brew dogma but we've been using this method for about a year now and haven't lost a batch.

ThreeSheetz said:

That has become our standard method. "Brew Day" stress went way down and the cost went down too because we no longer buy ice for the cold crash. Make sure you use a "hop sock" or something that allows you to remove the hops at the end of the boil or your IBU will be more than the recipie called for.
I guess the main thing to focus on is getting the wort down to pitching temperature the next day. When the boil is done, we leave the brew pot lid off and use a temperature alarm device to notify us when the wort has cooled down to say 155* F before putting the lid on to keep further airborne "bugs" out. This helps the wort to cool faster. Then, just let it sit on the stove and don't remove the lid again until ready to transfer the wort into your carboy and pitch your yeast. If you live in a hot place this method might not work so well but where we live even in the summer, it gets cool enough in the evenings that I only have to point a fan at the brew pot for a couple of hours the next morning before it's down to ideal pitching temp.
Anyway, this goes against home brew dogma but we've been using this method for about a year now and haven't lost a batch.

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I think you are apples and oranges here. He is talking about holding the wort, unboiled overnight and completing the boil the following day, not doing an overnight cooling to pitch. The only issue I can see is a potential for unintentional souring if you happen to have a stray bit of lacto get into your mash. Then you end up with a "kettle sour".

No experience with this method, but I have read of people doing it. IIRC, some reported that their FGs were consistently lower than projected and the assumption was that with the long, progressively cooler mash rest the amylase enzymes had more time to work, which dried out the beers. Contamination was a concern in all of the discussions, but I don't recall anyone having a recurring issue.

I have mashed at night and sparged the next morning and my tun was still over 140 degrees. No souring of any sort. I was pretty impressed, though I have not done it since.

As long as you are not mashing overnight I don't see anything wrong with it. Just drain into your boil kettle, off the grains, and put the lid on and you should be fine for a day or so. Really, it's not all that different then using extracts.

DrFun said:

Really, it's not all that different then using extracts.

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DrFun, would you explain this, because I don't see the connection.

botigol said:

DrFun, would you explain this, because I don't see the connection.

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Extracts are just wort that's been boiled down/condensed. There is no mash down on brew day. You start by boiling.

Mashing a day (or more) before, then storing that wort (not on the grain) would eliminate the mash on brew day and you jump straight to the boil.

That is why I was saying they are similar, and mashing a day early should be just fine.

ThreeSheetz said:

That has become our standard method. "Brew Day" stress went way down and the cost went down too because we no longer buy ice for the cold crash. [...]

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That's No-Chill brewing...not the same thing as the OP's scheme...

Cheers!

botigol said:

No experience with this method, but I have read of people doing it. IIRC, some reported that their FGs were consistently lower than projected and the assumption was that with the long, progressively cooler mash rest the amylase enzymes had more time to work, which dried out the beers.[...]

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A proper mash-out would seem to be required.
That would stop the enzymes in their tracks...

Cheers!

I was thinking of it from the product point-of-view, not process, so I see where you're coming from now.

day_trippr said:

That's No-Chill brewing...not the same thing as the OP's scheme...

Cheers!

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Yes indeed! Right you are. My bad for not carefully reading the original post.

This is so funny. I was thinking the exact same thing Sunday morning while brewing. If you do try it let me know how it works out.

Maybe try rising the temp after the sparge to something like 170-180? That should work as mashout (to avoid the issue someone mentioned about low FG due to extended conversion) as well as pasteurize the wort to try to minimize the risk of unintentionally souring.

I have read that simply mashing at a higher temp can help to reduce the increase fermentability caused by overnight mashing.

How much higher may be a trial and error project ..... guessing 3-5 degrees.

I have done overnight mashes a couple of times. Mash in, watch some TV, check the temp and go to bed. Then begin the boil first thing next morning. Only issue I had was a big stout wicking out of the pot via the bag and making a big mess of my insulation towels. I used a fermentation heat belt to assist with holding temps. Was surprised at how well the temps held. No noticeable issues with the beer, though this was 8 hours rather than 24.

Once on a brew day I carried out the mash and sparge, then had to leave the house unexpectedly. This was at about midday, so I left the wort in the BK with the lid on until I got home at around 8pm when I carried out the boil and it ended up being a really great beer. I was worried but on this occasion there were no ill effects and I guess that potentially is about as long as leaving it overnight.

I recently completed a full volume BIAB overnight mash with no issues. It was an IPA so I wasn't worried about my beer possibly being drier. I'll use this process again since I liked breaking the schedule up around family time.

Edit: I did use a reflectix jacket and sleeping bag around my kettle and only lost 10F over 7 hours.

I've done a couple of batches where I mash in the night before. Pull the bag up with the pulley and let it drain all night. The next morning I get the kids breakfast, me some coffee and then fire up the flame. No ill affects and the beers turned out great!

I do this almost every brew now. I've done it at least twenty times and have had no issues with contamination.

I'll start mashing after work, once the 1st, 2nd, and if applicable the 3rd runnings are in the boil kettle I bring it all up to 180 degrees, put a well fitting lid on the kettle, hold 180 for 5-10 minutes to allow anything that is riding on the cover to be sanitized then shut down power.
The next morning I start heating again and empty and clean the mash tun while the wort is coming to a boil. For me this works great.

I'm thinking of trying this to help with time management. I'll have to give it a shot.

I recently had to do that because of the weather. I had no problems, beer turned out great, as a matter of fact I'm drinking one right now! The boil will kill anything that might get in there overnight.

I'm in a similar boat with kids. I've had great success mashing in the night before, then starting my brew day by heating sparge water the next day. Works great, saves a few hours of daylight time. I've got a thread with details if your interested.

Its my preferred method. I've used it for am IPA, Lager, bitter, and Saison. All turned out great. Mashed in on Friday evening around 8pm. Gather my sparge water and when I wake up drain the tun as I heat the sparge water.

Makes for an easier brew with kids and also more enjoyable to wake up and start the boil. Usually done by 930am. The beers FG are usually lower but I've found if you mash higher (few degrees) and have a well insulated mash tun it's not really a problem.

I have done an overnight mash a few times now. I mash in around 11pm a couple degrees over my target, wake up drain while getting breakfast for my daughter, once she is settled I carry the pot outside and begin to boil. Saves time, beer was as good as anything from a normal batch. Efficiency increased a bit and fermentability increased so a bit drier than intended but I prefer dry so no problem for me. Another time savings is heating mash water overnight (or while at work) using a heat stick and temp controller.

I tried this method yesterday. I mashed Friday night with my recirculating eBIAB rig. I pulled the bag after mashing out to 170 and let the unboiled wort sit overnight. In 11 hours it dropped to 100 degrees F in my uninsulated pot. I boiled Saturday morning, chilled to 80 and them put it in the ferm chamber. Saturday night it was at 50 degrees and I pitched my lager yeast. This morning it's happily bubbling away.

How long can you strecth out doing the boil before getting too worried about infection or off flavours? 24-hours? 48-hours? Longer? Only reason I ask as I too am a homebrew loving father of a 10 month old and sometimes sleeping patterns are way off for my son and although I'd ideally like to pick right up where I left off the night before it sometimes doesn't pan out. Thoughts?

I don't know. Try to stretch it out and let us know! The worst case that I can think of is that you'll get a little kettle souring.

Jorb said:

I don't know. Try to stretch it out and let us know! The worst case that I can think of is that you'll get a little kettle souring.

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see my link to a thread on post 23 if you are interested in the details, but the research I did on this technique was that when you go below 140F, your in an area where souring bugs can take hold. Of course those would be killed whenever you get around to boiling, but whatever souring flavors they churn out before that time will carry through to the finished product. this may not matter to some but I dont like sour beers!

with that said, enjoy the technique I find it's a real timesaver to split up the brewday, but I take care to keep my wort above 140 when I do overnight mashing.

tyso22 said:

How long can you strecth out doing the boil before getting too worried about infection or off flavours??

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safest advice? dont go longer than a day.

in a pinch, if you just cant get to it then just bring it back up to mashout temp within 24 hours and let it rest another day. you've effectively pastuerized it again.

it works in theory. your mileage may vary.

I am busy and don't like killing my day off either. Here's what I have been doing with great success.

Thursday night: prep water, supplies, etc. get pot filled with strike water (30 min)

Friday before work 6 am: heat strike water and dough in (30 min)

Friday evening 10+ hours later: call wife and have her start heating sparge water while I am on my way home, get home and batch Sparge and start boil. Finish a brew day as normal (2.5 hours) so by 7:30 or so I am finished on Friday with still enough time to chill and watch a movie. Hope this helps someone. Oh and BTW no kettle souring or issues with too low FG. I think the Alpha and Beta Aml. Enzymes don't go working all night long. They only live so long 60-90 min. ... if what I have heard is correct.

This ended up working out pretty well. On the first night, I mashed, batch sparged and collected all the the sweet liquor in the brew kettle. Pre-boil gravity was 0.003 higher than expected, so not bad. Then, I covered it and just left in the uninsulated BK on the stove.

On the second night, I started the boil when I got home from work and proceeded with normal processes. OG post boil was right on. Fermentation got going, as it usually does with a healthy starter.

Final gravity was 0.006 higher than predicted, but fermentation was definitely complete, as confirmed by two identical gravity readings 48 hours apart. My guess is that higher FG was probably a result of mash temp being a few degrees higher than called for in the recipe, which would have impacted fermentability of the wort.

I tasted the final product this weekend, an oatmeal stout. It will benefit from some conditioning, but it wasn't too bad after a week in the bottle. It definitely confirms that the 2-night brew process is viable, at least in my mind.

Next time, I will probably take the advice of one of the posters and bring the wort up to 180 in the BK before shutting down on the first night, just to make sure I kill off any bugs that might potentially sour the beer.

Jorb said:

I tried this method yesterday. I mashed Friday night with my recirculating eBIAB rig. I pulled the bag after mashing out to 170 and let the unboiled wort sit overnight. In 11 hours it dropped to 100 degrees F in my uninsulated pot. I boiled Saturday morning, chilled to 80 and them put it in the ferm chamber. Saturday night it was at 50 degrees and I pitched my lager yeast. This morning it's happily bubbling away.

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I kegged this batch over the weekend. It still needs time to lager but I can't detect any off flavors. I'm calling the overnight mash a success.

I did a small batch (3 gallons BIAB) mash last night. Before bed I pulled the bag, let it drain, then placed it into a colander inside of another bowl. I placed the lid on the kettle, wrapped some towels around the lid and went to bed. This morning I poured the remaining wort from the colander into the kettle and started the boil.

I've done this method before even with larger batches and haven't had a problem. I will most likely continue to do this b/c it saves time and works better with my schedule.

I'm going to try this method this weekend.
Schedule will look something like this.

Friday night - mash and vorlauf. Collect sweet wort and heat to 180° and cover and wrap my BK in blankets

Saturday morning - continue boil as normal.

We'll see if this batch turns out without any off flavours.
If not I'll probably use this method a bit more often considering I have a 5 month old daughter who gets the majority of my attention.

I like that more are trying this. As an improvement to time management, I would suggest the "overnight" mash as opposed to "mashing the day before".

With the overnight mash, you could be sleeping during the mash and saving time. If your collecting the wort the night before, you're not saving any time, but just breaking the session.

JMO cheers