Overnight Mashing

[cornyandy]

Hi all

I remember someone a while back I think it was MyQul discussing overnight mashing. I wondered how well this technique works and whether there are any real pitfalls to the method. Can the mash get too cold would be my main thought.

Cheers

A

 

[Covrich]

Yes it can.. if you're going to do it I think you need to make sure you can keep the heat loss to an absolute minimum.. I think 50ºc is the lowest you will want it to drop..

I am sure he will answer but I think MyQul gave it up

 

[ezraburke]

To my mind there isn't going to be a great deal of issue with it but, again, MyQul did give a really good explanation of this the last time someone asked.

Longer mash = more sugars, ergo Overnight mash = ??? profit?

 

[cornyandy]

Cheers guys

 

[geetee]

We should think about what we are trying to achieve in a mash, that is turn the starch into sugar. two enzymes are responsible for this and the mashing range is a bit of a compromise between the two to leave a fermentable wort with (or without depending on choice) some body.

I think I am right in saying that the conversion of starch to sugar is not reversible so once this is achieved in the first 60 minutes or so what effect will a drop in temperature have on the wort? A rapid drop will certainly halt any further conversion but not sure if it will have any negative effect or if the lower temperature will extract any undesirables, at a lower temperature this is unlikely.

Once mashing is achieved does anyone know why there is a lower limit, 50°C has been quoted, for a temperature drop if the wort is left? I am not sure it will have any detrimental effect on the already mashed grain.

 

[GHW]

I think the main issue is the cooled wort sitting on the grain for enough time to let wild yeast etc present to take hold. I could be wrong though.

 

[geetee]

I think the main issue is the cooled wort sitting on the grain for enough time to let wild yeast etc present to take hold. I could be wrong though.

Since this is pre boil I do not think the yeasts would survive 60 or 90 minutes of a rolling boil, this is the whole point of the boil to sanitise the wort.

 

[beechwood]

very good method, like you say the main concern is heat loss, but if you can insulate it well then you'll have a good brew and eff. will be very good. I've only done it once with an IPA recipe and it turned out great!! :thumb:

 

[GHW]

Since this is pre boil I do not think the yeasts would survive 60 or 90 minutes of a rolling boil, this is the whole point of the boil to sanitise the wort.

I thought there were various nasties that could survive but am not exactly commenting from a position of authority!

 

[YeastFace]

Under 50℃ can pose as a breeding ground for lactobacillus, a bacteria as opposed to a wild yeast. Optimum is about 38℃, but it can survive and grow above this temp. Once lactose has soured the wort, boiling will not help as the PH will have already been reduced.

 

[Covrich]

Yeah I thought that under 50 could get micro bacteria which could sour the wort and boiling would be too late..

 

[geetee]

Under 50℃ can pose as a breeding ground for lactobacillus, a bacteria as opposed to a wild yeast. Optimum is about 38℃, but it can survive and grow above this temp. Once lactose has soured the wort, boiling will not help as the PH will have already been reduced.

Nice one
That's a fairly plausible explanation. I think the boil would kill the organisms but with the damage already done with souring due to low temp lactobacillus.

If there's a limit I always like to know why!

 

[cornyandy]

Makes a lot of sense overnight mashing without some temp control is probably a no no but it was an interesting thought.

 

[MyQul]

Yes, I did a number of overnight mashes.

I manged to not lose more than about 11C over about 11hours. I would start the mash at 69C, however a quite unfermentable wort was never a problem because extended mash gives a more fermentable wort so this countered the initial high mash temp and I also seemed to get a good efficiciency too

The reason I started doing overnight mashes was to break brew day up over three days. I now no longer do overnight mashes as MrsMQ usually goes out about 11am to classes so while I'm waiting for her to go out I usually just put the mash on about 10am then start the main part of brew day as soon as she's gone out so there's no real reason for me do the overnight mash now

 

[mike77]

I've done it with no real problems. Did notice a strong smell of DMS (sweetcorn), however this boils off. Good way to break up a brew day.