Brewing over multiple days

If you let a mash sit out for an extended period of time there is a good chance you will begin to have a lot of lacto growth and will produce a tart or sour beer depending on the length of time you let the lacto grow. This method can be used in berliner weisse beers and is called a sour mash. While boiling will kill the lacto, the damage is done and the beer will more than likely have that tart twang to it.

 

I just brewed a berliner weisse for the first time. It was nice to get to spread out some of the work, and it's one of my favorite styles. I mashed and sparged normally an let the wort sit for a couple days to sour up. Just added some raw grain in a mesh bag and let the lacto do its thing. 3 days later I took the bag out and started the process as usual from the boil. Also a nice 15min boil to boot. Probably the least stressful, for lack of a better word, brew I've made yet. Hopefully it comes out good.

 

To echo what others have said, sour mashing can can be spread out over the course of a few days, but the brewday can be chopped up as well with out souring. There were tons of threads on the old forum about over-night mashing, ie, mash your grains on Friday night, bundle it up, and leave it over night until morning when you run off, sparge, boil, chill, pitch, ferment on Saturday morning, or even mash before work in the morning, then runoff, sparge, boil, chill, pitch, ferment after you get off. Just don't leave the clean up for a few days, rancid grains are vile, and stuck on wort is difficult to remove, and can mold (or grow souring bacteria that can transfer and infect your wort depending on what you wait to clean).

 

To OP: to be perfectly clear, what they are describing is a 'sour mash' which is something you normally don't want to do unless you are brewing a specific style (like a berliner weiss) that calls for it.

You could, however (I suppose), freeze your wort and brew later without picking up sour lacto (a bacteria).

 

From what I have read, Lacto will ferment some sugars but does not produce alcohol so I would assume that it could theoretically take away some of the fermentable sugars which could lower the abv. This I am not positive on but it is just my line of thinking, someone please correct me if this is inaccurate.

 

Berliner weisse beers are traditionally sweetened post fermentation and prior to serving which is an attempt to take away some of the tart flavor which some find less desirable.

 

I'd do it rather than throwing away a batch of wort, but I would try pretty hard to not have to do it.

 

If you were to bring it up to a boil for maybe 15 minutes before putting it in the fridge (Sealed of course) that might keep it from souring in 24 hours. Your best bet would be to boil briefly, chill, seal, fridge.

Any sour type beer would work with a sour mash. You can sour it slightly to add some twang to a Saison or Irish Dry Stout, you can sour it fully to start on an American Wild, Flanders Red, Oud Bruin, Lambic, Gose, Berliner Wiesse. Just make sure you do it right... mashing, then leaving it sit for 4 days won't just sour the mash, it will putrify it, lots more stuff than lacto can grow depending on temp and exposure to oxygen.

 

One time I split up a brew over two days.

My first all-grain batch I did a brew in a bag technique but it was so cold outside (brewing in my garage) it took forever to get the water up to temp. Because of this it was too late for me to finish brewing that night. So I covered the pot and let it sit overnight and finished the next day. The wort went from ~150F to about ~40F and it took me even longer to get it up to boiling the next day, I kind of wish I had just finished the beer the previous night.

As for leaving the wort out overnight before boiling, there was absolutely no lactic twang perceivable, but as I said, it was really cold out so that probably cooled the wort quickly enough that it didn't stay in the ~100F range for very long, which is where lacto thrives.

So basically you can split it up, but because of other factors, you will probably wind up spending even more time.

 

As for the concerns about lacto from an overnight mash - If you use a clean, fairly airtight cooler (which you should have anyway) and mash high it shouldn't be that much of a concern. Just dough in at 160, shut the lid, and don't open it again until you're ready to sparge.

If you did that, I would be very surprised to see a worrisome amount of any microbe. As far as effect on the finished product, I can't really say without trying it myself first.

 

What might one expect from this long of a "sac. rest"?

-Will efficiency be greatly affected by letting the grains mash for 10 hrs?
-If the desited mash temp was 150, I'm asuming the mash would drop significantly overnight. Are there any adjustments to recipe design that should be made to account for long "rests" at lower temps?
-Is tannin extraction an issue?

 

I can't answer any of those with anything but speculation. If you started at 150, I imagine you'd end up with a highly fermentable, thin bodied wort. In the BYO article where the guy makes the all-grain 20 percenter, he mashes overnight. I can't recall what the temp drop was but his goal was to get as fermentable a wort as possible.

 

I am about to try splitting it up by mashing and collect on a Friday evening, cover the pot and put all the cleaned mash equipment away. Then when I get up Saturday morning I'll start up with the boil. This is a good process for back-to-back days.

 

I did an overnight mash a year or so ago for a Cream Ale. Temp dropped from 154 to 148 over 9 hours -- not too bad, IMO. And evidently not long enouh to develop any lacto. It fermented down to 1.002! It's fortunate that I wanted this beer super dry. A very effective technique, but I would advise extreme caution.

 

Another way many brewers split up their brew time is with "no chill" brewing. Basically, they mash and boil, but delay pitching the yeast until after the wort has cooled at a much slower rate than would have happened with a wort chiller or icebath. I think this became popular because of water conservation, but it also provides the opportunity to time shift the brewing steps.

 

I mashed, collected, and put it directly into a clean/sanitized carboy about 2 months ago. Went and played hockey. Then threw it back in the BK 3 days later and brewed it. Alot of people that have a hell of alot better pallet than I have been pretty impressed with the beer, and there's no souring going on in it.