Overnight Mash - Temps?

[WestMichBrewer]

Excuse me if this is covered elsewhere - I couldn't find what I was looking for with the search...

I was wondering if leaving a mash go overnight, with the temps naturally dropping off, would result in the lower-temp enzymes having their way with all the sugars and leaving a highly-attenuable wort where it may not be desireable.

Thanks in advance!

 

[HausBrauerei_Harvey]

Excuse me if this is covered elsewhere - I couldn't find what I was looking for with the search...

I was wondering if leaving a mash go overnight, with the temps naturally dropping off, would result in the lower-temp enzymes having their way with all the sugars and leaving a highly-attenuable wort where it may not be desireable.

Thanks in advance!

I had a thread on this last spring, lots of info there, but to answer your question: yes, you want to bump up your standard mash temp for a 1 hr mash when going overnight. I did 3 degrees with great sucess, although you'll find 3-5 degrees listed out there if you dig.

I did 6-8 batches with overnight mash this spring/summer and they worked great. things I did to ensure low heat loss: used my smaller mash tun so the tun was filled with liquid (~2/3 of my boil vol), saran wrap the cooler lid, cover with blanket, I was only seeing about 8 degree drop over 12 hours. My mash always stayed about 140 so no souring was noted, ever.

Since this fall i've been doing a hybrid approach which maximizes time with my young kids: I get my strike water in my pot the night before and mill my grains, then on brew day I spend ~30-60 minutes from when I get up getting doughed in, then I spend time with the family until after lunch when the kids go down for naps and I finish out the brewday. Wife is happy and I'm happy, it's a win-win.

 

[Jim311]

I'm a novice, but I decided to do a little research. I pulled up John Palmer's page to help myself understand a little better. Maybe it will help you. It looks to me like alpha and beta amylase convert starch to sugar in different ways, and simultaneously given the right circumstances... BUT...

"The temperature most often quoted for mashing is about 153°F. This is a compromise between the two temperatures that the two enzymes favor. Alpha works best at 154-162°F, while beta is denatured (the molecule falls apart) at that temperature, working best between 131-150°F."

So essentially, your recipe is going to call for a temperature that either favors one, the other, or both, and these starches are going to be converted into sugar very quickly, leaving not a whole lot of residual starch for the other type of enzyme, IF the temperature didn't denature it to begin with. For this reason I don't believe there is any risk whatsoever leaving your mash overnight. Essentially the outcome is decided almost immediately in the mash.


http://howtobrew.com/book/section-3/how-the-mash-works/the-starch-conversion-saccharification-rest

 

[DurtyChemist]

I'm a novice, but I decided to do a little research. I pulled up John Palmer's page to help myself understand a little better. Maybe it will help you. It looks to me like alpha and beta amylase convert starch to sugar in different ways, and simultaneously given the right circumstances... BUT...

"The temperature most often quoted for mashing is about 153°F. This is a compromise between the two temperatures that the two enzymes favor. Alpha works best at 154-162°F, while beta is denatured (the molecule falls apart) at that temperature, working best between 131-150°F."

So essentially, your recipe is going to call for a temperature that either favors one, the other, or both, and these starches are going to be converted into sugar very quickly, leaving not a whole lot of residual starch for the other type of enzyme, IF the temperature didn't denature it to begin with. For this reason I don't believe there is any risk whatsoever leaving your mash overnight. Essentially the outcome is decided almost immediately in the mash.


http://howtobrew.com/book/section-3/how-the-mash-works/the-starch-conversion-saccharification-rest

Palmer himself has said a lot of information from this website is vey outdated. Not sure if he said it to sell his newest book or because people were quoting it so often for so long and never discussed how old it was.

 

[Jim311]

Are you disputing this information? While I don't take John Palmer's information as gospel, I think the gist of it is correct, that most of the conversion happens very early in the mash and at specific temperatures, and that the OP doesn't have anything to worry about. If anything, it will simply help his efficiency. I don't think "this information is old" is really helpful unless you provide some other information that states otherwise.

 

[dstockwell]

What I did on my last brew BIAB.

Full volume no sparge, strike water 156, mash temp 148. Stirred about every 25 minutes or so. After 75 minutes my temp was at 146, left covered till morning temp 138, just continued on as normal. Since this was an IPA I needed the lower mash temp, next brew will likely have higher mash temp.