# Mashing At Room Temperature



## argon (26/3/12)

I'm considering setting up the brewery for an auto start HERMS, where I mash in at room temp the night before, then on a timer the HERMS starts and raises to my desired rest temp prior to lautering and ready for me to attend. I know some people do this, especially a couple that use Braumeisters.

Some of the reading I have done (brukaiser, palmer, and forums) has suggested (really by way of unsupported heresay) that leaving the mash at or around room temp may lead to a sour mash or similar to an acid rest, due to the lacto present on the grain. Yet this has not been confirmed and there is very little info that I can find to support or suggest otherwise. I understand however, that a traditional acid rest is typically done between 30C and 52C. Whereas room temp (for me at least) is about 24C.

Below is some of the studied ranges of temperatures when mashing. As can be seen anything below 30C is ignored. So what happens below that mark?







Enzyme

Optimum
Temperature
Range
Working pH Range

Function

Phytase

30-52.2F

5.0-5.5

Lowers the mash pH. No longer used.

Debranching (var.)

35-45F

5.0-5.8

Solubilization of starches.

Beta Glucanase

35-45F

4.5-5.5

Best gum breaking rest.

Peptidase

45-55F

4.6-5.3

Produces Free Amino Nitrogen (FAN).

Protease

45-55F

4.6-5.3

Breaks up large proteins that form haze.

Beta Amylase

55-65.5F

5.0-5.5

Produces maltose.

Alpha Amylase

67.8-72.2F

5.3-5.7

Produces a variety of sugars, including maltose.



So what would the effects be if I were to leave the mash at 24C overnight (approx 10hours) prior to raising to sach temp 66C?


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## MHB (26/3/12)

Mashing in the night before was a fairly common practice in pre-industrial brewing, Kunze mentions the process and notes that you get better yield and some other improvements, mainly from getting all the enzymes into solution, but that the costs outweigh any benefits (scarcely important to home brewers).
Pay to remember that tap (read well/river...) water in Europe might be 4-6oC in summer which is very different to our 15-20oC.
If you have a Braumeister you can either set it at any temperature in manual mode for as long as you like, or you can program each of the five steps for up to 255 minutes (4 Hours) so you could quite easily use the first two zones to give you a nice long mash rest (or Lactic Acid Rest if you want to make a sour beer) then still have three zones for the rest of your brew.

One enzyme you didnt mention (there are about 30 we could be looking at) is Maltase, produces 2 Glucose from a Maltose, very important in the formation of Banana in Wheat Beer. I suppose mu point is there could be some unexpected outcomes; it might pay to do some very simple beer so you can easily identify the difference between the overnighter and the same beer brewed by more conventional processes. One thing I live by is that Everything you do affects the beer

Have talked to Les the Weis Guy about doing a Berliner Sour this way; just dont know if I could really drink 50 L of it.
Keen to hear how this works for you
Mark


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## DJR (26/3/12)

Mark, you've reminded me of this:

http://www.aussiehomebrewer.com/forum/inde...st&p=701521

In there is a PDF from Danstar where they talk about starting a mash at 30C and doing some split-fu to get a Maltase rest. maltase is active around 35-40C, also Lacto sour territory if left too long :icon_vomit:


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## the_new_darren (26/3/12)

All the above enzymes will work (and be working) below 30 C, albeit at a slower rate.

The only overnight mash I have done definately produced "larks vomit" aroma and flavour. I would avoid doing it if you can.

tnd


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## Florian (26/3/12)

I do overnight mash ins quite a bit where the mash sits at around 25 degrees for up to 12 hours prior to starting the regular mash schedule. I do this purely for convenience as it allows for a quick start in the morning. 

I really have not noted any difference in the finished beer, although I have to say I'm always a bit vary about leaving it for too long, especially in the morning when the temperature in the garage rises. 

I haven't really analysed this properly yet, but I do seem to taste just a hint of sourness (with a slight tingling on the tongue) in the mash in the morning, and from memory there are also heaps of tiny bubbles rising up from the mash once I start the pump, which I haven't really noticed on 'normal' mash days. 

So no definite answers, but something that I will keep an eye on and also start noting down on which beers I have done this as I tend to forget after a while (so thanks for the prompt, Argon).

:icon_offtopic: 

Mark, when doing a Berliner Weisse I would recommend doing your 'normal' rests first, then letting the wort cool down to 40 degrees. Chuck a handful of freshly cracked grains in there and leave it at 40 for as long as you dare (12 - 48 hours, I have done about 20 hours several times). boil or don't boil to your preference.


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## argon (26/3/12)

MHB said:


> One thing I live by is that Everything you do affects the beer


100% concur. I think I'll give it a shot and see how it goes. Something nice simple should be a good idea and note the results. 

Slightly :icon_offtopic: All this is just in an attempt to be more hands off during the brewday. It'd be so nice to come home from work after doughing in on my way to work in the morning and have the mash finalising the mash out. Then start the fly sparge process and come back when I know it's all done into a full kettle. Then next step is to have the electric kettle start up on a float switch. Could fwh and and have bittered wort waiting for me.


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## manticle (26/3/12)

Slightly different but as a serial step masher, I'd be very interested to see if there was much difference doughing in cold (tap temp in winter) and ramping through temp rests at a slow rate till you hit more traditional/common rests as opposed to just doughing in for those rests.

Obviously the opposite of what you are hoping to do with 'hands off' approach and maybe more hands on than I'm willing to do considering the amount of time I'd need to stir my esky with the immersion element.


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## pk.sax (6/5/12)

Left the damn stuck mash outside, but covered, overnight.

It's come down to ambient, of course, can't see any bugs in there and no sour taste that I can tell. What do you guys say, jug it and boil it or chuck it?

50/50 munich2 and wheat malt used. I think my gap was too narrow and got shitty husks, add that to the wheat and my pickup tube in the middle of the fb seems clogged.


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## manticle (6/5/12)

If it smells and tastes OK, I'd have a crack at boiling. Any lactic will get killed in the boil (may still affect flavour) but there's only one way to find out.


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## DUANNE (6/5/12)

practicalfool said:


> Left the damn stuck mash outside, but covered, overnight.
> 
> It's come down to ambient, of course, can't see any bugs in there and no sour taste that I can tell. What do you guys say, jug it and boil it or chuck it?
> 
> 50/50 munich2 and wheat malt used. I think my gap was too narrow and got shitty husks, add that to the wheat and my pickup tube in the middle of the fb seems clogged.



ive done plenty of overnight mashes and the beer always comes out fine, i say keep going and make some beer.


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## Bribie G (6/5/12)

:icon_offtopic: 

Waay off topic but re Practicalfool's stuck wheat mash, One of my house beers that's always available nowadays is a 50/50 ale/wheat malt American wheat. I've never had a "stuck" mash using BIAB and get very consistent mashes and results. 

I'd recommend BIAB when doing high-wheat brews - dead simple if you have some way of mashing in voile in your existing kettle and preferably a point for a skyhook.


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## pk.sax (6/5/12)

Thanks fellas. I am going with it. Collected ~20L of first runnings at 1045 then sparged another lot @ 1020 (after temp correction)
See how it turns out. Got some grain in the kettle but bah. I agree with Bribie though, voile + wheat seems to be a win. I was lining my tun with voile with the manifold and just got overconfident wih the new fb.

Also, original plan was to decoct but I started too late and couldn't be arsed decocting at that time of the night. 

Well, lesson(s) learnt. It's a 20L recipe and by the looks of it I've got ~ 35L of wort pre boil.

I hope it turns out half as good as the last stuck mash! Which I'm drinking atm 






Not a lot left.

PS: I also did a ferulic acid rest @ 45C as per braukaiser. Lots of new stuff tried out in this brew.


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