Overnight mash with grits?

[Tim Bulin]

Been busy last few days and still need to get my pre-pro lager brewed. Was planning on cooking the grits as a quasi decoction, now I'm thinking about just stabilizing the whole grist overnight at 152 or so then just mash out, sparge in the morning and brew. Any downside to letting the mash sit that long?

I have a stainless pot that fits inside my Digiboil, should be able to keep temp spot on overnight.

 

[Donoroto]

Been busy last few days and still need to get my pre-pro lager brewed. Was planning on cooking the grits as a quasi decoction, now I'm thinking about just stabilizing the whole grist overnight at 152 or so then just mash out, sparge in the morning and brew. Any downside to letting the mash sit that long?

I have a stainless pot that fits inside my Digiboil, should be able to keep temp spot on overnight.

Ben used to do overnight mashes to no harm. I feel it can’t cause damage.

 

[J A]

I have a stainless pot that fits inside my Digiboil, should be able to keep temp spot on overnight.

The relatively high temp of 152 is probably warm enough to avoid souring but that would be the down side.
Once you're over 148, the beta-amylase will denature relatively quickly so overnight isn't going to do much of anything beyond the first couple of hours. If you held lower than 148, those enzymes can stay active for many hours and down to much lower temps and continue to convert starches. The alpha-amylase will be activated and could take a while to denature but those enzymes tend to be fairly short-lived anyway.
It'll be interesting to take a gravity reading after 2 hours or so and then compare to the reading after the overnight period. Pay attention to your pH. You'd probably want to shoot for 5.4 or so.

 

[Tim Bulin]

The relatively high temp of 152 is probably warm enough to avoid souring but that would be the down side.
Once you're over 148, the beta-amylase will denature relatively quickly so overnight isn't going to do much of anything beyond the first couple of hours. If you held lower than 148, those enzymes can stay active for many hours and down to much lower temps and continue to convert starches. The alpha-amylase will be activated and could take a while to denature but those enzymes tend to be fairly short-lived anyway.
It'll be interesting to take a gravity reading after 2 hours or so and then compare to the reading after the overnight period. Pay attention to your pH. You'd probably want to shoot for 5.4 or so.

In that case maybe I should mash in the grits with a couple pounds of pilsner malt and mash the rest of the malt in the morning just combine the 2 for 60 minutes and business as usual.

 

[J A]

In that case maybe I should mash in the grits with a couple pounds of pilsner malt and mash the rest of the malt in the morning just combine the 2 for 60 minutes and business as usual.

You could do it that way if you're confident you won't sour the mash overnight. I'd do that if I were planning a whiskey mash for distilling but I don't like taking any chances on beers, especially when it comes to lagers.
I do a rice "decoction" like you're thinking but I just do a standard mash rests. I do let it go for a while - usually a couple of hours total - and always get really good efficiency. I dough-in with just the malt and while that's doing a protein rest, I'm boiling rice for 15 or 20 minutes to cook it. Then I dump in the rice and top up to my beta-rest mash thickness and let the HERMS make up the difference in temperature.
For corn, I've found it so much easier to just throw in a few pounds of flaked corn from the LHBS and be done with it. I tend not to use quite as much corn when I use it compared to the percentage of rice and rice is cheaper and easy to use in the regular store-bought form.

PS...consider some rice hulls. You'll be happy not to be messing with a stuck mash.

 

[Craigerrr]

A buddy of mine use to mash overnight on Friday night and boil in the morning. He got really good efficiency too if I recall correctly.

 

[Tim Bulin]

Wound up just doing a 90 minute mash, it was that or put it off until the weekend. So far so good, will have to see how it turns out.