Overnight Mashing ?

[matt76]

Will the boil kill Lactobacillus ?

Yes - in the same way the boil will kill off any other microbes. But what it won't do is rid you of the lactic acid they produce. I use lactic acid sometimes as part of my normal water treatment but you need to be careful as it has quite a low taste threshold. I think that's the issue, along with whatever pleasant/unpleasant stuff any other microbes or enzymes present might start to produce.

Also bear in mind that one way of making a sour beer is kettle souring where you deliberately spike unhopped wort with lactobacillus - you leave it for a couple of days around 35degC and then boil it and hop it as normal.

you must make sure they do not drop below 50c as Lactobacillus can then start to present itself which will ruin your beer

I'm curious about this, though it must be said, not curious enough to actually waste my time trying it! Considering the time and temperatures involved in deliberately kettle souring I wonder how quickly you'd notice the effects of doing it accidentally like this, so to speak. And I suppose there's also the issue of whatever other microbes or enzymes might be present (I'm sure there's a vomit taste/aroma producing one...).

Yes I do! Though only for 20l brews nowadays as like someone already said, it's a massive timesaver! I would also say that I do tend to get higher efficiencies by doing it. Bonus!

I tried it a few times and also got significantly higher efficiency too (from 70 up to >80% kettle efficiency as I recall). The issue for me is I'm not as laid back and chilled out as @pilgrimhudd and get far too obsessed over numbers! I stopped doing it because I found it difficult to predict what the extra efficiency would be and so plan my brews accordingly. I do wonder though, now I use a mash re-circ pump whether I'd see much additional benefit from overnight mashing.

 

[pilgrimhudd]

I tried it a few times and also got significantly higher efficiency too (from 70 up to >80% kettle efficiency as I recall). The issue for me is I'm not as laid back and chilled out as @pilgrimhudd and get far too obsessed over numbers! I stopped doing it because I found it difficult to predict what the extra efficiency would be and so plan my brews accordingly. I do wonder though, now I use a mash re-circ pump whether I'd see much additional benefit from overnight mashing.

Let me just say that whilst I agree, it's not a positive quality of mine.

 

[Redwulf]

I've been thinking about doing this for some time.

Is it just a case of setting the Grainfather up for a 9-10 hour mash and letting it run?

 

[Cheshire Cat]

Do people sparge after an overnight mash?

 

[peebee]

I have a digiboiler with a neoprene jacket around it. Would that suffice or do I need to get creative with tinfoil?

Tinfoil? Nah. The enzymes are well gone (especially the "beta" which is creating all the easily fermentable maltose) by half way through the night. But avoiding unintentional Lactobacilli involvement is probably no bad thing (see @UKSkydiver's post above [EDIT: And @crescent city Mike's post below!]).

 

[pilgrimhudd]

Do people sparge after an overnight mash?

Sometimes! Depends on volume I'm going for etc. As Matt alluded too I can be a bit slapdash with my measurements and this often makes up my mind on whether to sparge or not.

 

[crescent city Mike]

I wrote an article some time back on this subject. Here's a link.
https://crescentcitybrewtalk.com/overnight-mashing/Check it out and let me know what you think.

 

[Wigglebutts Brewery]

I BIAB overnight with sous vide device to hold mash temperature. The OG is about .002 higher, consistently, so it’s easy to adjust base grains. It’s a nice time saver.

 

[-Bezza-]

I've mashed overnight in my grainfather. The idea was to set the mash off on a Friday evening so that I can have a shorter brewday on the Saturday (kids, etc). A typical schedule might be:

50C for 30 mins (or however long before I remember to go back)
64C overnight
76C for 15 mins

Since working from home, I've tended to prep the water on a Thursday night and delay heating until the morning so I can mash in quickly when I wake up. Have a cuppa, sort the kids out, move to the next mash step which I hold for the whole day. When I'm ready to brew, I then mash out whilst heating the sparge water.

Efficiency has been great with all styles.

If you don't have a grainfather, using an inkbird to control the mash could work although it won't be quite so accurate.

 

[The Baron]

I do my mash then do a mash out at 78c this helps with keeping the temp up through the night. I then wrap it up in old towels etc to keep the heat in. I then set it on boil in the morning and do a sparge as it is heating up hen proceed as normal.
I once let my temp drop accidentally and it started the Lactobacillus off which gave it a cheesy smell but the boil killed this off but the taint remained.
I have also done a overnight mash for 15 hours and that went fine too so just set the mash steps to repeat it self as the max time it would allow the mash was for 3 hours so did 5 steps at that.
Efficiency is consistently above 80 BHE

 

[BridgeBrew]

Do people sparge after an overnight mash?

I did what i call a teabag sparge. I see how much water is required to make the wort up to the desired level after i've lifted the bag out of the Cygnet, heat the required amount to 75-79 degrees, then pour it over the bag of grains in a spare fermenting bin, then dung it up and down, and give it a squeeze like a teabag. Then throw it into the boiler.

 

[-Bezza-]

Do people sparge after an overnight mash?

Yes - still some more tasty sugars to collect.

 

[chrisb8]

Do people sparge after an overnight mash?

Yes, I use a 3 vessel system so roughly half the total water goes in the mash overnight and the rest in the sparge in the morning.

 

[UKSkydiver]

...I once let my temp drop accidentally and it started the Lactobacillus off ...

Do you recall what that temp was?
Thank you

 

[pilgrimhudd]

Do you recall what that temp was?
Thank you

I don't want to answer for the baron but I've read it's in the 50s.

 

[The Baron]

Do you recall what that temp was?
Thank you

I think it was mid 40,s from memory 45C ish

 

[UKSkydiver]

Let's hope it was more like 40s than 50s, based on what I did last night

 

[pilgrimhudd]

Let's hope it was more like 40s than 50s, based on what I did last night

You would have noticed I'm sure, I think it's got a bit of a whiff!

 

[The Baron]

Deffo 40's
I have gone as low as 54c a few times with no problem and as Pilgrim said you get a cheesy whiff if it is Lacto

 

[crescent city Mike]

The major purpose of mashing is to degrade proteins, gums, and starches in the grain. Conventional wisdom tells us to mash for an hour and then do an iodine test. There is a lot more going on in the mash than simply converting starch into sugars. What really illustrated this to me was an interruption in my brew day some years ago. At 25 minutes into a single infusion mash, I was called away. About 3 hours later I got back to finishing that batch of beer. After the boil, I chilled the wort and checked the OG. I found it 2 to 3 gravity points higher than expected. I pitched the yeast, snapped on the lid, and put it away to ferment. It nagged me for a while over how and why I got that extra gravity. I then remembered Dave Line’s “Big Book of Brewing” which was the first brewing book I ever bought. He suggested an overnight (8 to 10 hour) mash, but at a minimum, two hours. He went on to explain that the mashing is not complete when the iodine test indicates an apparent lack of starch. I fathomed that some of the starch, shielded in the larger pieces of the crushed grain, takes longer to hydrolyze and so more of it is converted over time. He stated that some of the malt sugars need further reduction to provide a balanced wort. This overnight mash also breaks up your brew day by allowing you to start the mash in the evening, let the mash work while you sleep, and then finish up the brewing the next morning.

I've used a multi-step mash with an overnight saccharification rest for most of my brewing over the last 20 years. It has served me well