Mash time length

[Nick667]

I usually mash for 60 mins but recently the wife caused me a few problems (?) with having to pick her up and drop her off during the mash of an American amber ale. It went a good 2 hours but I still got in a mash out and a sparge.. Temp stayed consistent during mash and it turned out to be a really good beer, so good in fact that I have been mashing 90 mins on all brews since then. I seem to meet all my numbers perfectly at around 75% eff and sometimes higher, 80ish.
Can someone tell me the pros and cons of mashing longer and if there is a to long?

 

[wide eyed and legless]

I usually mash for 60 mins but recently the wife caused me a few problems (?) with having to pick her up and drop her off during the mash of an American amber ale. It went a good 2 hours but I still got in a mash out and a sparge.. Temp stayed consistent during mash and it turned out to be a really good beer, so good in fact that I have been mashing 90 mins on all brews since then. I seem to meet all my numbers perfectly at around 75% eff and sometimes higher, 80ish.
Can someone tell me the pros and cons of mashing longer and if there is a to long?

There are some folk who do an overnight mash, I have done a 2 hour mash on a Mild at a lower temp came out really good, mind you I did cheat on the malt.

 

[Horatio]

What's the head retention like on the long mash beer?

I remember reading somewhere once that they mashed overnight and the beer didn't have good head retention...for those that care about good head retention that is.

 

[Nick667]

Head retention is excellent and the brews I have done since at 90 minutes are good as well. I bulk prime and bottle if it makes a difference.

 

[keine_ahnung]

Hi Nick,

mashing longer *usually* won't cause any problems.....depending on temperature! As with pretty much all things in the Mash, temperature is single largest factor, followed by pH.

Basically, the enzymes just have more time to work. However, you will reach a point, where they've finished their work.
Cons of leaving the mash too long are:
-increased exposure to oxygen
-increased extraction of tannins out of the grain-husks

If it sits around at 50-60deg for ages, that could be problematic. The Amylose (one of the components (approx. 20%) of Starch) can crystalise at 50-60deg.
Between 50-60deg is also where two of the protein-processing-enzymes (Endopeptidase and Exopeptidase) are active. Depending on your malt properties, this could have either a positive or negative effect on the head retention.
These proteins are also very important for you yeast - However!!! too many are bad ==> negative byproducts during fermentations
(as our lecturer in this topic says: it's a bit like us, a few sausages and eggs for breakfast is quite ok, but if you have 3 kilos of each, it's a different story..)

^but of a complicated answer, but basically: it all depends on the temp!
But up to a few hours is not a problem. (some of the mash programs in our brewery where up to 2 hours. e.g. Festbier with decoction mash)

 

[MHB]

Like to add to the above (which is on the money IMO), one thing that can still be active are some thermophilic Lacto producing bacteria. We all know how bad expended malt can smell the next day, so clearly even mash out temperature's (80oC) aren't killing it. Probably not going to matter over a couple of hours, but can become a serious factor if you are thinking of overnight mashing.

Overnight mashing really isn't a good idea. Not the same as "Digestion Mashing" an old process where the mash was soaked cool (<40oC) over night then heated in the morning (some people are doing this with good results)

One other observation, I had a customer who kept getting Boilovers, traced it back to blue mashes, he was using quite a lot of adjunct and his overnight mashes went from being Iodine normal, back to Blue by morning. I suspect it was small starch granules bursting as they slowly hydrated, naturally the enzymes that were needed to breakdown the starch were denatured. So his wort was worse for the longer mash. Need to learn more about small starch granules.....
Mark

 

[Coalminer]

I have done a few overnight mashes with no ill affects but always start at room temp for 3-4 hrs then ramp up to mash/mashout so ready to sparge & boil when I wake up

 

[Nick667]

Thanks so much for your info it really is helpful. The amber ale was dead clear in a very short time and is very popular.

 

[Quokka42]

Long mashes are common, but I know of know science or experience that they have any advantages. If your pH is correct there are rarely any problems either. If your pH is high some mashes will add more tannins.

 

[Edd Mather 6]

How Do All,
For what it's worth, i'd be happy with a Mashing time of around two hours!!
Cheers
Edd